GREATBASiN NATURALiSTMB^DRS HimbTf^ BrHihacr,; Youn^ Ufii*«fit79t^M^ '■m.^^.. ij^6eetles of North ahd^ ^**-^ehtr«merica** I laxpnGmiG Monog^ HARVARD UNIVERSITY Library of the Museum of Comparative Zoology 5REAT BASIN NATURALIST MEMOIRS Jumber 6 Brigham Young University 1982 The Bark and Ambrosia Beetles of North and Central America (Coleoptera: Scolytidae), a Taxonomic Monograph MUS. COM P. ZOOW- APR 1 4 1982 HARVARD CONTENTS Preface 1 Introduction 3 Biological Activities 4 Ecological Niche 4 Host Specificity 4 Host Selection and Dispersal 4 Climate 5 Hibernation and Estivation 6 Ecological Specialization 8 Food and Feeding Habits 8 Galleries 10 Gallery Patterns 13 Social Organization 13 Seasonal History and Development 16 Pheromones 18 Economic Losses 20 Ecological Role in a Primeval Forest 20 Host Susceptibility to Attack 20 Competition for Food 21 Relation to Fire, Slash, and Natural Disasters 22 Relationships with Fungi and Disease 23 Introduced Species 25 Control 27 Losses Attributed to Scolytidae 27 Natural Control 28 Applied Control 30 Classification 33 History 33 Taxonomic Position of Scolytidae 33 Key to the Families of Curculionoidea 35 Family Status of Scolytidae 36 Fossil History 37 Discussion of Characters 39 Phylogeny 41 Biogeography 44 Extraterritorial Affinities 44 American Biogeography 50 Origin of Tribes 51 Methods 53 Systematic Section 54 Family Scolytidae 54 Key to Subfamilies, Tribes, and Genera 56 Subfamily Hylesininae 78 Tribe Hylastini 79 Tribe Hylesinini 108 Tribe Tomicini 129 Tribe Phrixosomini 204 Tribe Bothrostemini 208 Tribe Phloeotribini 256 Tribe Phloeosinini 282 Tribe Hypoborini 348 Tribe Polygraphini 369 Subfamily Scolytinae 392 Tribe Scolytini 393 Tribe Ctenophorini 451 Tribe Micracini 510 Tribe Cactopinini 637 Tribe Ipini 649 Tribe Dryocoetini 706 Tribe Cryptiirgini 740 Tribe Xyloterini 745 Tribe Xyleborini 755 Tribe Cryphalini 850 Tribe Corthylini: Pityophthorina 916 Tribe Corthylini: Corthylina 1155 References 1311 Index 1327 No. 6 Great Basin Naturalist Memoirs The Bari^ and Ambrosia Beetles of North and Central America (Coleoptera: Scolytidae)^ a Taxonomic Monograph Brigham Young University, Provo, Utah 1982 Stephen L. Wood' PREFACE The first insect I examined critically and collected for permanent preservation was Trypodendron retusum LeConte. At the age of 14 years I was introduced to it by T. O. Thatcher on 21 June 1939 at Lehman Creek Canyon, White Pine County, Nevada, near the base of Wheeler Peak. The attraction was immediate and permanent. An important fac- tor in reinforcing that initial attraction was W. J. Chamberlin's (1939) The Bark and Tim- ber Beetles of North America, which kept the interest alive and served initially as a guide to its expansion. The human population explosion of this century applied increasing worldwide pres- sure on forests and agricultural resources to increase the efficiency with which their products are formed. Since bark and am- brosia beetles constitute an important de- structive element that interferes with this production and with the esthetic values de- rived from our forests, increased knowledge of these insects should be of value to our so- ciety in dealing with them. Because of the enormity of the task, I selected one small fac- et, fundamental in nature, for my contribution. The first and most fundamental step in the solution of a problem in biology is the accu- rate identification of the organism under in- vestigation. Without it, all else is mean- ingless, because effective communication is not possible. Among my first experiences in scolytid tax- onomy was the discovery that numerous er- rors in identification had been made. They were made partly because of a faulty species concept possessed by early taxonomists and partly becau.se of a consuming desire on the part of a few authors to indelibly engrave their names in the annals of science by nam- ing species they presumed were new to sci- ence. More recently, we have learned that the behavior of a population in nature deter- mines whether or not it is a species, not the taxonomist. Many of the early contributions must now be rejected as a result. Even so, those earlv contributions established the foundation on which we now build. There has been a tremendous need for a comprehensive review of the Scolytidae of North and Central America to aid in the identification of species and to serve as a guide and reference work in the training and 'Life Science Museum and Department of Zoolog)'. Brigham Young University, Provo, Utah 84602. Scolytidae contribution No. 72. Great Basin Naturalist Memoirs No. 6 in the professional work of entomologists, foresters, and others directly or indirectly concerned with these insects. This volume treats a sufficiently high proportion of the fauna and is based on sufficient research in- volving primary types that it should serve as an important standard of reference for sever- al decades to come. With the exception of a few cited in- stances, all the work is original with me. However, in the early stages of preparation of the manuscript, well-intended colleagues knowingly published as new to science sever- al species which I had in manuscript form in order to "make them available" to my study. As a means of self-preservation and to avoid an endless comedy of locating types, rewrit- ing manuscript, etc., all species new to sci- ence and almost all new synonymy were pub- lished as discovered. Those descriptions were originally written for the present work and were modified only slightly to get them into print in the minimum possible time. To this extent this work partly duplicates published literature. A working knowledge of the world fauna was indispensible to the present studv. Thus far, 45 species introduced into North and Central America from foreign lands were found. Most of them had been named as na- tive species and their true origins had not been suspected. As knowledge of the world fauna is increased, this number will expand. It will be most surprising if 10 to 20 addition- al introduced species are not now established and await detection. Tlie preparation of this work has been an educational experience far exceeding original expectations. It was conceived in 1952, al- though writing did not commence until 1967. It was scheduled for completion in 5 years; it took 12. This work is dedicated to those who unself- ish contributions to this aspect of my life made this study possible, most particularly to T. O. Thatcher, W. H. Anderson, ].M. Swaine, and W. J. Chamberlin; to my wife and children, who endured decades of hard- ship and sacrifice for it; and to those young enthusiasts who will find it useful, correct its weaknesses, and continue the work. The National Science Foundation sup- ported the project directly or indirectly through most of the period from 1959 to 1977. Appreciation is expressed to those officials and colleagues who made these grants possible. Publication of this volume was sponsored by substantial grants from the Boise Cascade Corporation, the Weyerhaeuser Company Foundation, and the National Science Foun- dation. Their concern and foresight in the support of basic research in forest science is recognized and greatly appreciated— and in this instance especially needed. They are out- standing examples of the support and inter- action that has and should exist between pri- vate enterprise and the scientific community. Following the completion of this volume, Schedl (1979) published posthumously a cata- log of the type material in his collection. In- cluded were (1) several neotypes, which have no standing in nomenclature because they were not published in a revisory work, and (2) numerous lectotypes. Although many of the lectotype designations are valid, a high percentage of the species involved had pre- viously selected lectotypes designated for them; complications pertaining to ownership of the material also cloud part of that action. Because the article did not become available until this volume was beyond recall, and be- cause the work needed to unravel this un- fortunate act was enormous, no attempt to deal with this problem was attempted here. INTRODUCTION The dramatic increase in the human popu- lation during the present century has focused ever-increasing attention on forests and their products. This once unhmited natural re- source no longer satisfies the demands placed upon it. These circumstances have led to an increased interest in forest protection and an awareness of the destructive capacity of for- est insects. We have learned a great deal about the biology and ecology of many de- structive forms and now know how to reduce or eliminate much of the loss. Although much has been accomplished, much more remains to be learned before a new ecological bal- ance in a managed forest is achieved. In the primeval forest an ever-shifting eco- logical balance existed between the natural reproduction and growth of trees and the depredations of insects, fire, floods, disease, and climatic factors. When great losses re- sulted from any one or a combination of these destructive agents, natural ecological succession gradually restored the balance. It wasn't particularly important that several himdred years might be required to restore the original forest. A managed forest must satisfy a multi- plicity of needs ranging from the most ether- eal esthetic end of the spectrum to the eco- nomic realities of tree farming at the other end. Losses from insects, fire, and disease are regarded as avoidable and action may be taken to reduce or eliminate them. Although insects superficially appear to be the least dramatic of the destructive agents in a forest, they actually kill more trees each year than the combined total of all other nat- ural factors (R. F. Anderson 1960:203). Among the insects, one group consisting of the two families Scolytidae and Platypo- didae, commonly known as bark and am- brosia beetles, stand alone in their destructive capacity. It has been estimated that, in the United States, 90 percent of all tree mortality is caused by insects and more than 60 percent of the total is caused by representatives of the Scolytidae (Anderson 1960:203). The Pla- typodidae, almost entirely tropical in distri- bution, equal or replace the Scolytidae in this role in tropical countries. For a variety of reasons the Platypodidae will not be consid- ered further in this volume. More than 6000 species of bark beetles have been named from throughout the world wherever woody plants grow. About 477 spe- cies occur in the United States, with approx- imately 179 of these, plus a few endemic spe- cies, extending their ranges into Canada and Alaska (Bright 1976). About 605 species are found in Mexico and about 632 in Central America; allowing for overlap in distribu- tions, there are about 1,430 species in North and Central America combined. Most species restrict their breeding activity to one or a limited number of host plant species. In addi- tion, most species have specialized ecologi- cally to infest only a restricted part of their host plant. For example, some species confine their attacks to the cones or fruits of their host, others infest only tiny twigs, others small branches, limbs, boles, or roots. Some breed only in shaded-out branches of stand- ing, living trees, others in felled or broken material, etc. A few are very aggressive and attack healthy, living tissue, and others prefer dying or dead plants. Because of the large number of species and the extreme diversity in their habits, bark and ambrosia beetle attacks on economically im- portant plants can be evaluated and mean- ingful corrective action taken only if species involved are correctly identified. In addition, research notes based upon incorrectly identi- fied specimens may not only be meaningless, but misleading. This volume was written to simplify the process of identification of Scolytidae for those who work with problems involving these insects. Coleopterists and zoogeographers will also find information compiled here useful in their work. Three noteworthy attempts have been made to classify North and Central American Great Basin Naturalist Memoirs No. 6 Scolytidae (Blandford 1895-1905, Swaine 1918, Chamherlin 1939). Almost as note- worthy are series of revisional and other tax- onomic articles relating to classification by Hopkins, Blackman, Wood, and Bright. This volume attempts to summarize and update their contributions as well as to add new in- formation not previously reported. BIOLOGICAL ACTIVITIES Ecological Niche Most bark and ambrosia beetle species live only in recently cut, injured, or unthrifty tis- sues of woody plants that are in the process of dying. In most genera, they complete one generation only in this material then abandon it to search for other material in suitable con- dition. Host tissues must contain sufficient moisture for the completion of development. Such material usually bears wilted or yellow- ish green leaves. Older host material usvially is unattractive to the beetles; however, a few species apparently prefer host material that is completely dead. Several other species nor- mally attack healthy, living tissue of vigorous plants and cause its death. A few species of ambrosia beetles (e.g., Cortlu/his colwnhianus Hopkins) are capable of attacking a living tree, completing a system of galleries, and emerging a generation later without killing the host, although a permanent scar remains in the wood. Bark and ambrosia beetles usually are the primary attackers of recently injured or felled woody plants. Most species complete their development in about 20 to 90 days then move to fresher material. Other wood- and bark-feeding insects usually arrive later or develop more slowly, thus reducing or eliminating competition. Those scolvtid spe- cies with longer life cycles and those arriving late in the ecological deterioration of their host usually encounter much greater com- petition for survival from other insect groups. Host Specificity Most Scolytidae are restricted in the num- ber and variety of host species in which they can successfully reproduce. In general, phloeophagous (phloem infesting) species tend to be more restricted or specific in their selection than are xylomycetophagous (wood- boring ambrosia beetle) species. The appar- ent reason for this difference is that the for- mer feed directly on host tissues, and the latter feed on fungal spores; any host on which the symbiotic fungus can survive will be satisfactory for beetle development. Only two known species (Coccotrypes, tribe Dryocoetini), one in Malaya and one in New Guinea, confine their attacks to Pterido- phyta. Representatives of 14 of the 25 tribes recognized here in the world fauna normally breed in Gymnospermae, but of the 10 most primitive tribes worldwide only the Hyla.s- tini, Tomicini, and Scolytini are included within these 14. It is of interest that all spe- cies of the Hylastini are restricted to the fam- ily Pinaceae of the Gymnospermae. Repre- sentatives of all tribes, with the exception of Hylastini, breed largely or exclusively in the Dicotyledoneae, although the American Po- lygraphini occur exclusively in conifers. Few- er than a dozen known species confine their activities to Monocotyledoneae, but only one of these represents a primitive group (Cne- sinus vestitus Eggers, tribe Bothrosterini). In addition to these, several species of poly- phagous Xyleboriis may also breed in various palm logs, but host preference is not involved in the selection. Within tribal or generic groups host specif- icitv may be extreme, with most species con- fining their breeding activity to one or to a very restricted number of host species. For example, American Scierus, Hylurgups, Hy- lastes, CarpJiohorus, Polygraphus, Cryphalus, Cryptiirgus, Dolurgus, Pityogenes, Orthoto- micus, Pityokteines, Ips, and Pityohorus are restricted to the Abietineae of Pinaceae, Phloeosinus to the Cupressineae or Tax- odioideae of Pinaceae (many Oriental species occur in other plant families), Phrixosoma to the Guttiferae, Dendrocranuhis to the Cu- curbitaceae, Pseudopityophthorus to the plant genus Quercus, etc. The Bothrosternini, Cryphalini, and Xyleborini are unusually polyphagous. Host Selection and Dispersal Scolytid beetles are dependent upon their power of flight to move from their brood tree to a new host. The original pioneer beetles 1982 Introduction are guided in their flight (primary attraction) by volatile oleoresins, terpene hydrocarbons, alcohols, or other substances given off by the recently injured or dying host tissue (Ru- dinsky 1966). When such odors are in the air, flight is oriented and usually proceeds up- wind to the source; when attractive odors are not detected, the dispersal tends to be random. The objective of this flight is the location of new host material, but the use of that mate- rial varies with the reproductive readiness of the insect. When the gonads are mature, as is usually the case, a new tree in which brood can be produced is sought. In many species, however, the beetles seek the green bark of a healthy host, where they bore into the outer phloem and feed or hibernate for a period of time before emerging to seek a host in which to reproduce. In some species the construc- tion of feeding timnels is not a regular habit but may fimction as an emergency means of waiting for the availability of suitable host material. At times these emergency tunnels are formed in hosts not normal for the species and have resulted in numerous erroneous host records. The original pioneer flight may be taken by either the male (e.g., Ips) or the female (e.g., Dendroctonus) beetle, but, regardless of which sex makes this flight, the habit is con- sistent for the species. Once a pioneer has found a suitable host, it bores in then begins to release a chemical sex attractant or phero- mone that attracts both males and females of its own species to that host. Thus, subsequent flights are oriented by both tree volatiles and pheromones until sufficient beetles are pres- ent to overcome any resistance to the attack that might be given by the host. Climate The factors which constitute climate, that is temperature, precipitation, humidity, soil moisture, sunshine, air currents, and air pres- sure, are of extreme importance in determin- ing the distribution and abundance of bark and ambrosia beetles and of the predators, parasites, and other organisms with which they are associated. Except for a few hours once each generation, during which time the dispersal flight takes place, these insects live entirely within the host plant, where the sub- strate and micro-environment are remarkably constant. This constancy in the immediate environment has had an obvious effect on in- tra-populational variability and apparently has reduced the effect of climate; but certain long-range effects are clearly evident. For example: 1. In Canada and Alaska fewer than 10 percent of all scolytid species are xylomy- cetophagous, and more than 90 percent are phloeophagous; in Costa Rica and northern South America approximately 60 percent are xylomycetophagous, and 40 percent have other habits, only part of which are phloeophagous. 2. Of the genera treated in the present study 50 percent (including far more than half the species) are largely or entirely tropi- cal in distribution, 30 percent are largely or entirely temperate in distribution, and 20 percent occur in both areas (but a dis- proportionate majority of the species in these genera are tropical). Comparatively few spe- cies are found in Alaska and Canada and, among those that do occur there, the distri- butions of a high percentage of them are re- stricted to southwestern British Columbia or to the southern tip of Ontario. 3. Scolytid species are comparatively un- common in deserts. A surprisingly high per- centage of the genera present in desert re- gions are restricted to desert or semi-desert areas {Chaetophloetis, Cactopinus, Steno- cleptus, etc.). 4. Temperate groups of scolytids may ex- tend their distributions into tropical areas along mountain ranges, providing the alti- tude is high enough to assure cool temper- atures, and a dry season is sufficiently pro- nounced to produce conditions suitable for the growth of their host plants. 5. Unusually high or low temperatures cause fluctuations in bark beetle populations over extensive areas. High and low lethal temperatures vary from species to species, from one developmental stage to another, and with the length of exposure (Rudin.sky 1962). This principle has been used in con- trolling certain species by exposing infested material to solar radiation during the hot summer season. It is also noted that, in a fall- en log, one species may infest the uppermost 6 Great Basin Naturalist Memoirs No. 6 (hottest and driest) surface, another may in- fest the sides (moderately cool), and others may infest the lower (coolest) area. In addi- tion, it is observed (Dixon and Osgood 1961:3, Wood 1963:17-18) that, in a given widely distributed species, more generations are completed at the southern than at the northern limits of the range, presumably the result of a longer season of favorable temperatures. 6. Prolonged drought may reduce the re- sistance of trees to a point where they cannot resist bark beetle attack (Rudinsky 1962:342). Many .species of twig borers cannot be reared successfully outside a growth chamber unless melted wax or liquid plastic is painted over cut ends to conserve moisture. It is also a common practice of bark beetle collectors to cut limbs of trees and place them in a cool, .shaded place, where moisture loss is mini- mized, so that they might remain attractive to scolytids. 7. In their dispersal flight bark and am- brosia beetles normally move only short dis- tances (a few meters) from one host to anoth- er. Occasionally, however, these weak fliers are caught by the wind and carried distances up to 15 km (Rudinsky 1962). Their occur- rence on certain oceanic islands suggests flights of considerably greater length. 8. Flood waters undoubtedly have had an effect on bark beetle populations, either by covering infested hosts and drowning the lo- cal population, or by carrying infested mate- rial downstream to initiate an infestation in a new area. Living larvae immersed in water cooled to near the freezing point have been kept alive by me for 200 days. Infested logs presumably could be carried completely im- mersed for hundreds of kilometers during spring floods and still produce living beetles. Hibernation and Estivation Unfavorably high or low temperatures, such as those encountered during the tropical dry season or the northern winters, cau.se a cessation of beetle activity. The life cycle usually is .synchronized with the seasons, and the most resistant stage predominates when the period of physiological stress begins. Esti- vation, the period of inactivity during hot or dry weather, occurs principally in tropical regions and apparently may be as short as two weeks or as long as five months, depend- ing on the climate. In all probability, this in- activity is not controlled hormonally (except Xylehorus dispar (Fabricius)), but may be in- terrupted at any time by the return of favor- able temperature and moi.sture. High temperature.— Bark temperatures of 42-50 C (107-122 F) usually cause dis- organized behavior of bark beetles and, in time, thermal paralysis, and death. Higher temperatures, 50-55 C (122-131F), are lethal in a shorter period of time. Graham (1920, 1924) found in Minnesota that the thickness, color, .structure, and sur- face features of bark and the light intensity, solar attitude, and angle of incidence in- fluenced the subcortical temperature of logs. He found that midday subcortical temper- atures reached maximum levels of 45-60 C, with the highest levels in dense, dark, thin- barked, rough logs. The highest levels of 60 C (140 F) were reached in Pinus strobus on a day when the air temperature was 40 C (104 F). Patterson (1930), using Pinus contorta logs in Oregon, recorded midday subcortical tem- peratures of 43-51 C (110-123 F) while air temperatures were 24-26 C (75-78 F); sub- cortical temperatures in adjacent standing trees were 22-24 C (72-75 F). Miller and Keen (1960) summarized 45 years of studies on the effect of high temper- atures on Dendroctonus brevicomis LeConte. Decreased activity was noted at 35 C (95 F) and thermal paralysis at 38 C (100 F). Cur- rents of warm air with low humidity could be fatal to larvae at 38-41 (100-105 F) within 30 minutes. At "normal" humidity paralysis commenced at 42-43 C (108-110 F) and death at 43-46 C (110-115 F). No larvae sur- vived even brief exposures at 48 C (118 F). In field tests, sustained temperatures of 38 C (100 F) resulted in 34.2 percent mortality, and at 49 C (120 F) 100 percent mortality. Low temperature.— The mortality of bark beetles due to low temperature appar- ently is an important factor in determining local abundance and the expansion and con- traction of distributions. Beal (1933) reported that the egg stage of Dendroctonus brevicomis LeConte was the most resistant of all immature stages to low 1982 Introduction temperature. Air temperatures of -21 C (-5 F) did not affect the hatching of eggs; how- ever, temperatures as low as -12 C (10 F) re- sulted in 43 percent mortality of larvae in the moist cambium (moisture level 200 percent of dry weight) while larvae in the outer bark (moisture level 30 percent of dry weight) suf- fered almost no mortality. When exposed to -21 C (-5 F), mortality of larvae was 100 percent, pupae 90 percent, and adults 100 percent in the moist phloem. Pupae and adults in the dry, outer bark suffered almost no mortality at this temperature. Miller and Keen (1960:71-73) reported cold periods in the winters of 1924 (-29 to -32 C or -20 to -25 F) and 1932-1933 (-29 to -39 C or -20 to -38 F) in which Dendroc- tonus brevicomis , \arva\ mortality was esti- mated at 25-80 percent and 50-90 percent, respectively. Unprotected summer brood lar- vae exposed in the laboratory at -18 C (0 F) suffered 20-50 percent mortality, at -21 C (-5 F) 75 to 100 percent mortality, and at -21.7 C (-7.5 F) almost always 100 percent mortality. At 10 C (50 F) larvae become sluggish and dormant; at -9.5 to -12.2 C (15-10 F) larvae freeze but recover when re- turned to warm temperatures. A "brief" ex- posure of eggs at -21 C (-5 F) resulted in 90 percent mortality; none hatched after expo- sure at -23 C (-10 F). Results with the expo- sure of pupae were about the same as for lar- vae. Adult mortality commenced at -10 C (14 F) and was complete at -12.2 C (10 F). Massey and Wygant (1954:23-24) studied the effect of low temperatures on cold-hardy Dendroctonus nifipennis (Kirby) and report 100 percent mortality at -26 C (-15 F) for adults and -34 C (-30 F) for larvae. Low temperatures in Colorado in 1951 extending in some areas down to -49 C (-56 F) killed approximately 75 percent of the over- wintering larvae above the snow line; adults hibernating below the snow line at the bases of their hosts were not affected by these temperatures. Hopkins (1909b:24) attributed the com- plete extermination of Dendroctonus frontalis Zimmermann in Virginia and West Virginia to the unusually cold winter of 1902-1903. Activity range.— From the above data it would appear that bark beetles are active at temperatures of about 10-38 C (50-100 F). Daterman, Rudinsky, and Nagel (1965) re- port that the minimum threshold air temper- ature necessary to initiate flight ranges from 12-13 C (54-55 F) in Pseudohylesinus nebu- losus (LeConte) to 20-22 C (68-72 F) in Sco- lytus unispinosus LeConte. It is noted, how- ever, that once flight is initiated it may continue even though temperatures may de- crease to 5 C (41 F) in Pseudohylesinus spp. The spring flight usually commences when daytime temperatures reach this threshold. As the season advances and temperatures in- crease, the period of flight is restricted to the early morning and evening periods to avoid desiccation. Hibernation.— Whether or not the life cycle is synchronized with the seasons, most scolytids do not hibernate in the true mean- ing of the term. Instead, when subcortical temperatures fall below the threshold activi- ty ceases; when temperatures rise above that threshold activity is resumed. In Xyleborus dispar (Fabricius) true hibernation occurs (French and Roeper 1972); however, the mechanism governing it has not been investigated. The winter may be passed in any stage of development, but the overwintering stage is constant and characteristic in each species. The larval stage is the most commonly repre- sented. Most species appear to make no spe- cial preparations for winter; others bore into the sapwood (e.g., Scolytus rugulosus Miiller) or into the outer bark (some Dendroctonus); others fly to living trees where feeding tun- nels are excavated in green tissue (e.g., some Phloeotribus), or they overwinter in the duff on the forest floor (e.g., Ips, Trypodendron). Estivation.— This phenomenon has not been reported in the literature. In Costa Rica during the latter part of the dry season I found Metacorthylus velutinus (Wood) in an inactive state in radial tunnels 1-2 cm deep in a log too dry for reproduction. Apparent- ly, they were waiting for spring rains before resuming activity. Tropical Dendrocranulus apparently pass the wet season outside their normal hosts, then appear in large numbers as the dry season begins. Hibernating speci- mens were not found. Many tropical scolytids apparentlv ignore the seasonal changes ob- served by other insects and continue their re- productive activity throughout the year. Great Basin Naturalist Memoirs No. 6 Ecological Specialization Each group of organisms entering a new adaptive zone, as did the Scolytidae when they began to utiHze unthrifty and dying tis- sues of woody plants, soon discovers that its food resource is hmited and its greatest com- petitors for food and space are other mem- bers of its own kind. The resulting com- petition results in an adaptive radiation or ecological specialization along numerous av- enues that enables the group more com- pletely and more effectively to utilize the available food .source. For example, it probably would be phys- iologically impossible for one species of .scolytid to develop that could utilize both bark and wood of all woody plants in all parts of the world. Such an occurrence would subject that species to enormous population fluctuations and other natural disasters. It is of greater advantage to the group to develop a variety of species each specialized to meet the requirements of life in a particular cli- mate on specialized ti.ssue of a restricted host. This is essentially what has happened in the evolution of the Scolytidae. Scolytids utilize at least some representa- tives of gymnosperms and virtually all dic- tyledonous families containing woody plants. Few species inhabit pterydophytes or mon- ocots. While many woody plant species are not infested by any .scolytid .species, others (mo.st Pinaceae, etc.) are the host of numer- ous species. Wlien two or more species share the same host species, competition between them for space and food results either in ex- tinction of one of them or in ecological spe- cialization. Such specialization has resulted in the development of forms that live only in seeds or fruits (certain Amptus, Coccotrypes, Conophthorus, Hijpothenemus, Pagiocents, Spermoplithorus, etc.), others only in un- thrifty twigs and branches of living trees (cer- tain Carphoborus, Chaetophloeus, Hypocrij- plialus, Liparthrurn, Pitijoborus, etc.), others in cut or broken twigs and branches (certain Cryptocarenus, Cnesinus, Hypotfienemu.s, Pi- tycypht horns, Tricolus, etc.), others in sup- pressed seedlings in dense growth (certain Carphoborus, Pityophthorus, Xylechinus, etc.), others in the tops and limbs of over- mature trees (certain Ips, Phloeotribus, Pityophthorus, Scolytus, etc.), others in slash (certain Ips, Pityogenes, Pityophthorus, Sco- lytus, etc.), others in boles of standing trees (certain Dendroctonus, Ips, Phloeotribus, Sco- hjtus), others in butts and stumps (certain Dendroctonus, Dryocoetes, Gnathotrichus, Ips, Xyleborus, etc.), and others in roots (cer- tain Corthylus, Dryocoetes, Hylastes, Hylur- gops, etc.). Some species utilize leaves (cer- tain Cactopinus, Hypothenemus, Pseudo- thysanoes, Scolytodes, etc.), and a few live in herbaceous plants (all Dendrocranuhis, Hy- lastimts, certain Hypothenemus, etc.). Pa- giocerus frontalis (Fabricius) has been report- ed as a minor pest in stored com in South America, but not in the northern parts of its range. Several .species, particularly in the genus Hypothenemus, apparently are capable of living in almost any available source of plant material; for example, Hypothenemus eruditus Westwood was named from a series found boring in the cover of a book. It also may live in seeds, weeds, twigs, bark of the bole of large trees, and shelf fungi. Of great- est economic concern, however, are those species that infest healthy, living tissue, such as Conophthorus spp., Corthylus columbianus Hopkins, several Dendroctonus spp., Hypoth enemus hampei (Ferrari), Xylosandrus com- pactus (Eichhoff), and many others. Food and Feeding Habits The Scolytidae are among the few insect groups in which the adults burrow into the host plant for the purpo.se of depositing their eggs directly in the food substrate to be con- sumed by the larvae. The concealed tunnels (Fig. 1) offer a greater degree of protection than occurs in many groups; furthermore, the adults usually remain in their galleries to pre- vent the entry of predators and parasites into the gallery system, thus increasing the pro- tection given to the larvae. Several forms of feeding are associated with this habit. Herbiphagy, feeding upon nonwoody plants, is rare in the Scolytidae. Hylastinus obscurus (Marsham) breeds in the roots of various clovers and may become a serious pest. Chramesus pumilus (Chapuis) breeds in the larger stems of wild beans. Hyothenemus pubescens Hopkins breeds in the fruiting .stalks of grass; H. eruditus Westwood, H. 1982 Introduction Fig. 1. Galleries of Dendroctonus breiicomis on the lower bole of Pinus ponderosa. Tlie bark was removed to ex- pose the tunnels. (After Swaine 1914:17.) 10 Great Basin Naturalist Memoirs No. 6 areccae (Hornung), H. crudiae (Panzer), //. columbi Hopkins, and occasionally other spe- cies may breed in a wide variety of her- baceous vegetation, although they are not re- stricted to these plants. All Dendrocranulus species and allied Old World genera breed exclusively in the stems of cucurbitaceous plants. Spermophagy includes feeding on seeds and at least parts of the protective fruit that covers them. In North America this habit is best known in the Conophthorus species that infest cones of Pinus, particularly those with large seeds. Spermophagy is much more com- mon and widespread among tropical genera such as those listed in the preceeding section (Ecological Specialization). Myelophagy, feeding on the pith of small stems, evidently is considerably more com- mon in the American tropics than in other parts of the world. Several species of Pityoph- thorus have this habit in the United States and Canada. Almost all species of the Both- rosternini, all Cnjptocarenus and Micracisella, several species of Hypothenemus, and a few species of Araptus, Chramesiis, Scolytodes, Tricohis, etc., also have this habit. A few of these species are extremely aggressive and destructive. Phloeophagy, feeding on phloem tissues of the inner bark, is the habit usually associ- ated with this family and is the basis for their common name; however, fewer than half the species in the family are phloeophagous. In temperate areas of the world the most com- mon genera burrow in the cambium region of their hosts and thereby produce the charac- teristic engravings that show on the surface of peeled bark or wood. Most of the Hylesi- ninae, Scolytini, Ctenophorini, Dryocoetini, and Ipini fall into this category. Xylophagy includes living in and feeding directly on the xylem or wood tissues. Al- though almost all ambrosia beetles may be partially xylophagous, they are excluded from this category since their principal food is not xylem. Apparently all xylophagous spe- cies are associated with fungi that alter the character of the wood consumed, but the my- celium does not form a conspicuous element of the diet. Xylophagous forms include Chra- mesus xylophagus Wood, two species of Chaetophlocus, all Dendrosinus, Lymantor, Hylocurus, Micracis, and Thysanoes, Scoly- todes midtistriatus Wood, and many other isolated examples in other genera. I am una- ware of any nutritional studies involving a xylophagous species; the food source and the modified color and texture of the wood near a tunnel suggest that symbiotic organisms are involved in some way. Xylomycetophagy includes the cultiva- tion and utilization of a symbiotic fungus as a food source. The term "ambrosia beetle" has been applied to the Scolytidae and Platypo- didae having this habit regardless of their phylogenetic origin or relationships. The habit apparently has arisen independently in the Platypodinae of the Platypodidae and in the Scolytidae in the Bothrosternini {Both- rosternus), Hylesinini {Hyleops of Australia), Scolytini (Camptocerus), Scolytoplatypodini (Scolytoplatypus of Asia and Africa), Xylote- rini, Xyleborini, and Corthylini. More than 99 percent of all species of Platypodidae and more than half of all tropical Scolytidae have this habit. Galleries The gallery systems of the Scolytidae are unique and represent the product of a long and complicated evolution. These beetles probably arose prior to the Cretaceous geo- logical period from a saprophytic group of beetles found imder bark. Early representa- tives probably formed crude cavities in the phloem after entering the bark through in- juries or the excavations of other insects. The earliest galleries probably were of the cave type similar to those presently seen in Meco- pebnus (Platypodidae), many Scolytodes, Cry- phalus, Procryphalus, Trypophloeus, and phloeophagous Coccotrypes, in which the eggs are deposited individually or in small clusters and mixed indiscriminately in the frass. Later the eggs were placed in specially prepared niches and packed in a mixture of boring dust held together by an adliesive se- cretion, as now seen in Liparthrum. Further specialization of the system included the ex- tension of various irregular pockets for the protection of the eggs; these eventually be- came egg galleries and may occur either with or without egg niches. The addition of the polygynous and xylophagous habits rrtodified the basic gallery only slightly. 1982 Introduction 11 The gallery system of a typical phloeo- phagous or mvelophagoiis species consists of the following parts: 1. Entrance tunnel: The entrance hole (Fig. 2: parts 5, 11, eh) is usually located at a leaf scar, axil, crevice, or other irregularity in the bark; however, many Micracis and Cor- thifhis, and genera allied to these two, com- monlv select smooth areas. This short, simple, cylindrical tunnel is usually directed oblique- ly upward in its passage through the bark to facilitate frass removal and, apparently, to protect the entrance from precipitation. In xylophagous forms (Fig. 2: parts 12-14, 16-18) it is a direct radial tunnel per- pendicular to the outer surface. The diameter of the entrance tunnel is very slightly larger than the beetle making it, such that its body might effectively prevent the entry of pre- dators, parasites, or other unwanted intruders when a defensive position is taken in the en- trance timnel. A major task of one of the par- ent beetles is blocking the entry. 2. Nuptial chamber: In many groups, when the entrance tunnel reaches the cam- bium a flattened (tabular) cavity is usually ex- cavated (Fig. 2:5, 11, NC). This oval or ir- regular chamber usually has a diameter about three to five times greater than the length of the beetle excavating it. The entrance tunnel usually enters the nuptial chamber at its low- est margin to facilitate frass removal. In the most primitive gallery systems adult partici- pation in excavating the tunnel ends at this point; as indicated above, eggs are scattered indiscriminately or in clusters and larvae en- large the excavation. In most groups, how- ever, additions are made. The nuptial cham- ber is best developed in groups in which the male forms the initial parts of the system, particularly when polygyny occurs. It is part- ly or entirelv eliminated in other groups, par- ticularly when a male does not enter the gallery. 3. Egg galleries: When a female enters a tunnel she forms one or more egg galleries (Fig. 2:1-16) that extend along the cambium following a course away from the nuptial chamber. They usually are straight, but curve characteristically in some species. Very com- monly it is possible to identify the genus or even the species from the gallery system without seeing the beetles that made it. In their primitive form egg galleries are no more than indefinite pockets along the mar- gin of the nuptial chamber. In their more ad- vanced form they are more slender and long- er, and in their most advanced form they are cylindrical, very slightly larger than the width of the beetle forming them, and very long. In most genera the female cuts egg niches along the margins of the tunnels; in others these are absent. The egg niches usual- ly are as wide as the female head and about as deep as wide; their size, shape, position, and spacing usually are characteristic. Long egg galleries in thick bark usually have venti- lation tunnels placed at irregular intervals on the outer side. These extend to near the sur- face of the bark but rarely open to the sur- face. Their function is not definitely known but they might serve as turning niches, as sources of oxygen, for ventilation and tem- perature control, or as easily opened avenues of escape in an emergency. 4. Larval mines: After hatching the lar- vae may (a) feed exclusively on mycelial or other materials supplied to them, (b) enlarge the parental chamber, usually feeding com- munally (in congress), or (c) form individual larval mines. The latter habit is by far the most common in temperate regions. Larval mines may be little longer than the larval body {Pityoborus, etc.), or exceedingly elon- gate (some Scolytus, etc.). Though the egg gallery, nuptial chamber, and entrance tun- nel are usually kept entirely free of boring dust, the larval mines are closely packed with frass. In many species the larval mine en- graves both wood and bark throughout its length; in others part or all of the mine may be entirely in the wood or entirely in the bark. Near the end of the larval mine an ex- panded area is usually cleared to form a pu- pation chamber where transformation occurs. It may be formed in the cambium region, deep in the xylem, or in the outer bark. Fol- lowing transformation many species emerge immediately through individual exit holes; others require a maturation feeding period before they emerge. The brood of phloeo- phagous and myelophagous species rarely emerges through the parental entrance hole, although it does in Pityoborus, in many Cryphalini, and in most ambrosia beetles. 12 Great Basin Naturalist Memoirs No. 6 Fig. 2. Tlie common kinds of gallery systems formed by Scolytidae: 1, biramoiis longitudinal; 2, monoramous lon- gitudinal; 3, stellate, radiate, or miiltiramous; 4, cave-tunnel (two postoviposition feeding tunnels are shown); 5, stel- late system of Ips concinnu.'i showing entrance hole (eh), nuptial chamber (NC), egg gallery (et), egg niche (ep), larval mine (Ig); 6, modified stellate; 7, transverse stellate; 8, transverse biramous; 9, longitudinal stellate- 10, transverse bi- ramous with larval mines added; 1], modified stellate with nuptial chambers entirely in the bark; 12, ambrosial stel- late without cradles (Xylchortis); 1.3, ambrosial cave-tunnel (wood grain runs left to right; in 12 wood grain runs top to bottom); 14, ambrosial stellate with larval cradles {Monarthmm)- 1.5, pith tunnel {Micracisella): 16, ambrosial stel- late, modified, with cradles (poor example oi Gnathotrichus); 17, 18, ambrosial branching tunnels (Xuleborus ohesus). (After Swaine 1918:13.) 1982 Introduction 13 In xylophagous and in most spermo- phagous forms the same basic parts of the gallery system are found except that they are distnibuted in a three dimensional system rather than two. In ambrosial forms the larval mines are usually reduced to larval cradles just large enough to accommodate the new adult or they are eliminated. In most groups having larval cradles the eggs are deposited in niches and the larva enlarges this niche into the cradle as it grows {Monarthrwn, Trypoden- dron, etc.). In some Corthylus the parents form the completed cradles and deposit the eggs only when the ambrosial fungus is well established. In other groups that lack egg niches and larval cradles, the larvae may de- velop in the adult galleries (many Xyleborus) or the larvae may form a common, tabular chamber parallel to the grain of the wood. Numerous variations of these basic patterns occur. Gallery Patterns Scolytid parental galleries might be classi- fied as follows (Fig. 2): 1. Cave -tunnel: A simple cavity formed (1) in the cambium region, (2) in the wood, or (3) in the pith of small stems. When this type of cavity is formed by ambrosia beetles (Xylo- sandnis), most or all of the cavity usually is formed by the larvae. 2. Uniramous gallery: a simple, (a) lon- gitudinal or (b) transverse egg gallery either in the phloem or xylem tissues. Primitively, a conspicuous nuptial chamber occurs at or near the entrance; this chamber may be re- duced to a turning niche or, in galleries made by previously mated females, it may be eliminated. 3. BiRAMOus gallery: a system in which two egg galleries arise from the same nuptial chamber. In its more advanced form the nup- tial chamber may be eliminated and the pat- tern is a simple fork. The galleries may be (1) longitudinal, (2) transverse, or (3) diagonal. Among phloeophagous groups it is the most widely distributed pattern. It also occurs in some xylophagous groups. 4. Stellate, radiate, or multiramous gallery: This type of system is most com- mon in polygynous species. Three or more (19 were found in one species of tropical Pi- tyophtJiorus) egg galleries extend from the nuptial chamber. The egg galleries may be (1) straight and radiate in all directions away from the nuptial chamber, (2) curved so as to (a) parallel the grain of the wood, (b) cut transversely across the grain, or (3) form a pattern independent of the grain. 5. Branching galleries: This type of sys- tem is rare and apparently occurs only in species commimally sharing the same en- trance hole, as in Dendroctonus brevicomis LeConte, Cladoctonus boliviae Wood, appar- ently Microborus spp., and a few other spe- cies. In this system, beetles arriving late at the host use a previously made entrance tun- nel and follow the gallery of another pair for a distance before starting their own branch tunnel. Phloeophagous species that form tim- nels of this type do not remove the frass from the gallery, but pack it tightly a short dis- tance behind the working area. This is also one of the most common systems formed by ambrosia beetles, although the entrance may or may not be commimal. 6. Ambrosia beetle galleries: Ambrosia beetles construct gallery systems of the five basic types listed above except that (a) they are adapted to a three dimensional system rather than two, and (b) the larvae may ex- tend and modify the original parental tunnel, as indicated in the preceding section, either the larvae or adults may form series of larval cradles in either one or two ranks both above and below the egg gallery (ambrosial Corthy- lini, Scolytoplalypodini, and Xyloterini). In many of the Xyleborini the larvae form tabu- lar extensions of the parental tunnel along the grain of the wood that sometimes are enormous when one considers the size of the beetle. Soci.\L Organization As with other woodboring Coleoptera in which the adults form tunnels and enter the host to reproduce, the Scolytidae have devel- oped a distinctive subsocial behavior. Most species infest hosts that are unthrifty or in a somewhat living though injured state. When the beetles bore into these living tissues the host reacts by exuding quantities of resin to plug the wound and expel or drown the 14 Great Basin Naturalist Memoirs No. 6 Fit;, o. Pitch tube of Dendroctonua hrevicumis show- ing an unsuccessful, expelled beetle on a pitch tube. (Af- ter Keen 1955:2.) intruder (Fig. 3). If only one or a few beetles are present a vigorous host usually is success- ful in resisting the attack. Most scolytids overcome this resistance through mass at- tacks that overwhelm the resistance of the host. The communication necessary for coordinated attacks is accomplished through secondary attraction with pheromones re- leased by the beetles. Tlie original pioneer beetles that first enter a new host release one or a combination of chemical substances (pheromones) beginning about the time their tunnels reach the cam- bium region. These volatile substances are in the fecal pellets that are mixed in the frass and expelled from the tunnel by the beetles. The odors carried by the air currents have a strong attraction to both males and females. Upon arrival at the host under attack the members opposite in sex from the pioneers, seek out an entrance tunnel and, through the process of auditory, tactile, or possibly chem- ical signals, or a combination of these, the potential mate is identified and admitted to the timnel. Following mate identification, pheromone production ceases. A masking or repellant pheromone may also be released af- ter the mate is admitted (Rudinsky 1968). An extensive annotated bibliography on second- ary attraction in Scolytidae was published by Borden and Stokkink (1971) and Borden, VanDerSar, and Stokkink (1975). As indicated above, one of the principal functions of pheromones is the attraction of potential mates. The secretive habits of these insects, coupled with their ability to commu- nicate through olfactory and auditory signals, has led to the development of unique repro- ductive behavior. When the potential mate arrives at the entrance hole, in certain spe- cies, it stridulates actively. This stridulation in male Dendroctonus pseudotsugae Hopkins causes the female inhabitant of the new gal- lery to stop the production of the aggregat- ing pheromone and to admit the male (Ru- dinsky 1968). In Platypodidae this courtship apparently includes tactile as well as audi- tory elements, and in certain genera (Diapiis) the female mandibles are equipped with spe- cial processes used for identification by the male, which are shed after this event. The elaborate sexually dimorphic sculpture and ornamentation of the head and declivity in one or both sexes of numerous species of Scolytidae suggest that tactile stimuli are used extensively in the Scolytidae for mate identification at the entrance of the gallery. Chemical stimuli also function in this court- ship activity, in addition to basic secondary attraction (Rudinsky and Michael 1972). There are four distinct types or levels of social organization associated with reproduc- tive behavior. These are (1) monogamy, (2) normal (heterosanguineous) polygyny, (3) ex- treme (consanguineous) polygyny involving arrhenotokic parthenogenesis, and (4) gy- nogenetic parthenogenesis. Monogamy is the most common and wide- ly distributed habit. It occurs in all Platypo- didae (except Protoplatypus), in all Hylesi- ninae (except Polygraphini and some oriental Phloeosinus), in Scolytini (except some neo- tropical Scolytus), in Ctenophorini (except a few Scolytodes), in all Scolytoplatypodini, Cactopinini, Crypturgini, and Xyloterini, in phloeophagus Micracini, in part of the Cryphalini (Cryphalus, Hypocryphalus, 1982 Introduction 15 Stegomerus), in part of the Dryocoetini {Den- drocranulus), and in part of the Corthyhni {Pityobortis, Conophthorus, Corthylus, many Araptus, and a few Pifyophthorus). In mon- ogamous species either sex may initiate the boring of a new gallery, but the habit is con- stant within a species. For example, in Den- droctonus and most Scolytus species the fe- male performs this function, but in Phloeosinus and Corthylus it is the responsi- bility of the male. In most monogamous spe- cies, after pairing has occurred, the female is responsible for boring egg galleries, the for- mation of egg niches, and laying of eggs and caring for them and the larvae (if the larvae remain in the parental tunnel). The male keeps the nuptial chamber and entrance tun- nel clean and expels the frass from the en- trance hole. He also blocks the entrance with his body to prevent the entry of predators and other intruders. Kalshoven (1959:170) ob- served rapid pumping movements of the body (stridulation of a disturbed individual?) and quick, short movements backwards and forwards in the timnel near the entrance and suggested that these activities might be asso- ciated with ventilation of the gallery system. Although similar action has been observed in other Scolytidae, its function has not been investigated. In monogamous species both sexes usually participate in the construction and care of the galleries. However, in many forms one or both sexes may abandon the tunnel as soon as egg deposition or hatching is complete, and in a few Scolytus the male may mate on the bark surface and never enter the gallery sys- tem. One or both sexes may then participate in the formation of a second, third, or even fourth set of galleries (Simpson 1929). The division of labor in tending the gallery system apparently has led to the evolution of much of the observed sexual dimorphism in the groups. Most of these features occur ei- ther on the head or elytral declivity and, as suggested above, many of them may be asso- ciated with mate identification. However, others clearly are associated with frass re- moval, preparation of the niches for the eggs, or cultivation and care of the ambrosial fungi. The most radical modifications include the head and antennae {Camptocerus, Hylo- cunis, Corthylus), pronotum (Amphicranus, Pityoborus), elytral declivity {Ips, Mon- arthrum, Amphicranus), abdomen (Scolytus), and legs (Xyleborini). Polygyny occurs in many tribal groups and undoubtedly has originated independently several times. Two distinctive types of poly- gyny are recognized: (1) Heterosanguineous and (2) consanguineous polygyny. In hetero- sanguineous polygyny the male flies to the new host and (almost always) excavates the entrance tunnel and nuptial chamber. He then admits about two to five females to his chamber (up to 19 females were admitted in one neotropical Pityophthorus). The females then push the frass resulting from their activ- ity into the nuptial chamber. The male has the responsibility of ejecting their frass and of protecting the entrance hole. The function of each sex is about the same as in monogamous species. The advantage appears to be the greater speed and efficiency with which the host can be occupied. In addition, a portion of the more vulnerable attacking males can be lost to weather and predation without af- fecting the population. This polygynous habit occurs in Phloeosinini (some oriental Phloeos- inus), Polygraphini, Scolytini (certain neo- tropical Scolytus), Ctenophorini (polygynous Scolytodes), Micracini, most Dryocoetini, Ipini, and Corthylini (except several mon- ogamous forms and two species noted below). In most xylophagous Micracini, in Pseudopi- tyophthorus, and in some neotropical Sco- lytus the male is always associated with two females; a different number may characterize other groups. In consanguineous polygyny the males are incapable of flight and, consequently, they al- most never leave the brood chambers. The deformed, dwarfed, haploid males attain sex- ual maturity and mate very early and usually die before they are fully colored. The sex ra- tio of the brood in these species ranges from about 3-50 females per male. Both mated and unmated females may attack the new host. Entwistle (1964) reported that in Xylo- sandrus cornpactus (Eichhoff) unmated fe- males, and those that have exhausted their supply of sperm, produce only haploid males by facultative arrhenotokic parthenogenesis. The haploid males mate with either their mother or their sisters in order to produce diploid females (see also Norris and Chu 16 Great Basin Naturalist Memoirs No. 6 1970). Thus, an isolated female whether or not she has mated prior to isolation, is ca- pable of colonizing a new area. Since both males and females have been observed to wander outside their galleries, it is apparent that some outbreeding might occur if they enter other galleries. Due to the recency of the discovery of the genetic mechanism, it is only speculation that male haploidy occurs in other tribes with consanguineous polygyny. This habit occurs in many Cryphalini (Hy- potheneinuf), Cnjptocareniis), in a few Dryo- coetini {Coccotrijpes, Ozopemon), in all Xy- leborini, and in two species of Corthylini {Araptiis laevigatus (Eggers) and A. costari- censis (Schedl)). Reproduction by gynogenetic partheno- genesis was discovered in Ips tridens engel- manni Swaine by Hopping (1961, 1962) and was confirmed by Lanier and Oliver (1966). In this example it appeared as though the penetration of a sperm in the egg membrane is required to trigger a parthenogenetic re- sponse. Theylytoky, in which female off- spring are produced with no participation of the male, has not been reported but almost certainly occurs in a few species such as Bothrosternus foveatus (Blackman), where males are unknown. Seasonal History and Development Mate identification.— In all mon- ogamous and heterosanguineous polygamous species, the first step toward the production of a new generation, after the host has been selected and the new gallery is started, is the identification and admission into the gallery of one or more potential mates. The admit- ting sex has initiated the gallery and tightly blocks the entrance with its body in order to prevent the entry of a predator, parasite, or competitor. Mate identification to gain entry into the obstructed entrance may involve the exchange of sound stimuli (Rudinsky and Mi- chael 1972), behavioral stimuli (Petty 1977), and, apparently, chemical stimuli, or a com- bination of two or more of these factors. Fe- male Didpus (Platypodidae) have special mandibular processes that are shed after ful- filling a tactile function. Following mate identification, either a position for copulation is taken or else the chosen mate is admitted into the gallery. Mating.— As indicated in the preceding section, a diverse social order has had its ef- fect on mating behavior. In most species with heterosanguineous polygyny and in many phloeophagous monogamous forms (Dendroc- tonus, etc.) copulation takes place only after both sexes have entered the new gallery sys- tem. In the.se species it most commonly oc- curs while one member is in the nuptial chamber or turning niche and the other is in the entrance tunnel or at the entrance of an egg gallery. In this protected site it may oc- cur repeatedly throughout the period of ovi- position. In Platypodidae, Scoh/tus, Try- pophoeus, Procryphahis, and probably in other monogamous groups, copulation occurs when the female is partlv or wholly in the gallery, with her abdomen protruding above the surface, and the male is on the surface of the bark (Petty 1977). In the Platypodidae the male initiates excavation of the tunnel, but, following a courtship or identification ritual, he backs out of the burrow to admit her. Copulation then occurs and he follows her into the gallery (Browne 1961:38). In Sco- hjtus quadrispinosus Say the female starts the burrow and, after mating occurs, the male may then enter the tunnel or go in search of another female (Goeden and Norris 1965:772). Males of Scolytus as well as Try- pophloeus and Procryphahis (Petty 1977) commonly struggle for dominance by butting or pushing with the head until the loser is up- set and falls from the bark. In Cryphalus mat- ing may take place on the bark surface of ei- ther the brood or parental host (pers. obs.). Species with the consanguineous habit of po- lygyny have been observed on numerous oc- casions copulating in the brood chambers (pers. obs.). Eggs.— Scolytid eggs are smooth, oval, white, translucent, delicate objects varying in size from one group to another (Fig. 4B). In certain small Hylesininae (Carphohorus) the egg may be almost one-third as large as the adult body; in larger species (Dendroctoniis) they are proportionately much smaller. They vary in number in one gallery system from as few as 3 {Corthylus) to about 200 (Dendroc- tonus). The number of eggs apparently is smaller in ambrosia beetles and in those spe- cies inhabiting highly diverse tropical rain forests and greater in phloeophagous forms 1982 Introduction 17 Fig. 4. The four life stages of Dendroctonus hrcvi- comis: A, adult; B, eggs; C. larva; D, pupa. (After Keen 1955:3.) that breed in temperate forests where large stands of one or few host species pre- dominate. In some groups the eggs are depos- ited in clusters of about 4 to 20 (Try- pophoeus, Scolytode.s) or separately but packed in frass in the parental chambers (Chaetophloeiis); in Dendroctonus valens Le- Conte (etc.) they are deposited in rows in long or short grooves; in most scolytid species they are deposited individually in specially prepared niches and packed in boring dust that is held together by a secretion presum- ably of oral origin (probably from the max- illary glands). Hatching may require from as httle as 3 days (tropical Scolytodes) to as much as 30 days or longer (subarctic Den- droctonus). Variations in temperature may drastically alter the time required for in- cubation. Under ideal conditions the eggs of most species hatch in about 7 to 10 days. Larvae.— The larvae are white, legless grubs with lightly sclerotized heads (Fig. 4C). They do not change appreciably in form as they grow. Although studies by Thomas (1957) and Lekander (1968a) have greatly in- creased our knowledge, the larvae are poorly known and deserve considerably more study. The number of larval instars varies from two to five. Lekander (1968b) gives the following based mostly on European species: (a) those having five instars include Chaetoptelius, Hy- lurgopinus rufipes (Eichhoff), and Dendroc- tonus micans (Kugelann) (for a variety of rea- sons I suggest a reexamination of these species before five instars are accepted for any scolytid species), (b) four instars were re- ported for Dendroctonus pseudotsugae Hop- kins and D. simplex LeConte, Hylastes, Hy- lurgops, and Tomicus; (c) three instars occur in all Ipini (except Pityogenes hopkinsi Swaine, which he suggests is an error), Dryo- coetes autographus (Ratzeburg), Pityoph- thorus, Xylehorus, Hylesinus, and Poly- graphus; and two instars in Conophtliorus, Crypturgus, Cryphalus, and Ernoporus. The length of the larval period varies from as little as 12 days (estimated for some tropi- cal Scolytodes) to more than two years (arctic Dendroctonus). Under ideal conditions it ranges from about 30 to 90 days in most spe- cies. The larvae may feed in congress while extending the parental chamber (Cnesinus, Scolytodes, Dendroctonus valens), or they may form independent mines {Ips, Pityoph- thorus). Their tunnels may be long and tor- tuous {Phloeoborus, some Phloeotribus), or just 18 Great Basin Naturalist Memoirs No. 6 large enough to accommodate the adult body (Pityohorus, Monarthnnn). Most Xylehorus and Corthylus larvae depend entirely on tun- nels excavated by their parents. Pupae.— Usually, the end of the larval mine is enlarged slightly and cleared of frass to form a pupal chamber. In other forms the larva may bore into the wood {Scolyttis rugu- losus) or into the outer bark (Dendroctoniis approximatus Dietz) before forming the pup- al cell. The pupal stage (Fig. 4D) may range in length from about 3 to 30 days, but tends to average about 6 to 9 days under ideal con- ditions. It rarely is selected as an over- wintering stage except in areas where the winters are very mild. Adult.— Upon transformation to the adult stage (Fig. 4A) the beetles may emerge im- mediately, even before becoming fully col- ored (Scolytus), or they may require a period of maturation feeding before emerging (some Dendroctoniis, Ips). Many species fly from the brood host to a living host, where they excavate maturation feeding tunnels in living tissue before reaching reproductive maturity {Scolytus multistriatus (Miiller), etc.). Others use this as an optional habit only when suit- able host material is not immediately avail- able for rearing their brood. After com- pleting one gallery system it is not uncommon for the parent beetles to re- emerge and construct a second, third, or fourth system of tunnels to produce an equal number of broods. A previously mated fe- male will sometimes produce a second brood without the association of a second male, thus giving a false impression that parthenogenesis has occurred. A few old adults may survive the winter and participate in the production of the spring brood. However, a majority of the adults die in their tunnels after producing one brood. Chapman (1956) demonstrated that the flight muscles of parent adult Trypo- dendron lineatum (Olivier) deteriorate during oviposition and brood production, but re- generate later when flight is again required. Vite and Rudinsky (1957) present a technique for estimating the degree of maturity in each of the developmental stages of Dendroctonus pseudotsugae. The progressive appearance of various structures and pigmentation enabled them to estimate the approximate age of each developmental stage. Reproductive cycles.— As indicated in the preceding sections, scolytids are able to complete their life cycles in as little as 20 days or they may require at least two years. Temperature and moisture factors in the sub- cortical microclimate have a tremendous in- fluence on life cycles and can radically shorten or prolong them. Some species, such as Dendroctonus ponderosae Hopkins, have one annual life cycle closely correlated with the seasons. Others may have two or more generations per year equally correlated with seasonal change. Many species, however, have a succession of overlapping generations complicated by the production of several broods from a given set of parents each year, as in Polygraphus rufipennis (Kirby). Even those species usually follow definite annual patterns of emergence, flight, etc. Dendroc- tonus pseudotsugae in the southern Rocky Mountains apparently has a life cycle out of sequence with the seasons, but has predict- able outbreaks (Furniss 1965). In tropical areas cyclical activity in most forms is corre- lated with the dry and wet seasons and may be just as conspicuous as in temperate regions. Pheromones Bark beetle pheromones, airborne long dis- tance chemical messengers that announce to others of their species the location of host material or the availability of mates, have re- ceived much attention in the past decade. Since their main function is the coordination of activity in local populations, it has been supposed that they might also be used to dis- organize normal behavior patterns and there- by achieve control of economically impor- tant species. Pheromones have been reported in the Hy- lesinini (Hylesinus), Tomicini (Dendroctonus, Pseudohylesinus, Tomicus), Phloeosinini (Phloeosinus), Polygraphini (Carphoborus, Po- lygraphus), Scolytini (Scolytus), Ipini (Ips, Pi- tyogenes, Pityokteines, Orthotomicus), Xylote- rini (Trypodendron), Cryphalini (Cryphalus), and Corthylini (Pityophthorus, Gnatho- trichus) (Borden and Stokkink 1971). They apparently have not been reported from any species with the habit of consanguineous polygyny. 1982 Introduction 19 The pheromone of male Ips paraconfusiis Lanier consists of three terpene alcohols; I, (-)-2-methyl-6-methylene-7-octen-4-ol; II, ( + )-ri.s-verbenol; and III, ( + )-2-methyl-6- niethylene-2, 7-octadien-4-ol (Silverstein, Ro- din, and Wood 1966). Although none of these was an effective attractant alone, compound I in combination with either II or III was partially attractive. It is of interest that com- pound I was marginally attractive to Ips lati- dens LeConte, but I and II used together were highly attractive; the addition of com- pound III eliminated the response (D. L. Wood, Stark, Silverstein, Rodin 1967). Cam- eron and Borden (1967) report that female response to the male /. paraconfusiis phero- mone fluctuates with the season, being lowest in January (24.2 percent response) and high- est in May and June (76.6 percent response). D. L. Wood and Bushing (1963) found that the /. paraconfusiis pheromone appeared in the frass about 9-12 hours after males were introduced into preformed entrance tunnels. The substance is produced only after feeding commences, indicating that the precursor is ingested and metabolized or else tliat food activates specialized secretory cells; it is passed from the adult male in the fecal pel- lets (D. L. Wood, Browne, Silverstein, and Rodin 1966). Borden and Slater (1969) in- duced pheromone secretion by topical appli- cation of juvenile hormone, indicating that the pheromones are secreted. The sensilla tri- chodea on the antennal club are the olfactory recepters for these substances in Ips (Borden and Wood 1966). As examples of how pheromones function, the following is included. The principal sex pheromone of female Dendroctonus hrevi- comis, exo-7-ethyl-5-methyl-6, 8-dioxabicyclo [3.2.1] octane, designated as brevicomin, oc- curs in the hind gut (Silverstein, Brownlee, Bellas, Wood, and Browne 1968). Males of this species produce as their chief pheromone 1, 5-dimethyl-6, 8-dioxabicyclo [3.2.1] oc- tane, or frontalin (Kinzer, Fentiman, Page, Foltz, Vite, and Pitman 1969), this substance is the principal pheromone of female D. fron- talis Zimmermann (Renwick and Vite 1969). In D. hrevicomis, brevicomin attracts mostlv males and frontalin attracts females (Pitman 1969). In addition to the above, the phero- mone complex of both D. brevicomis and D. frontalis includes fran.9-verbenol in the fe- males and verbenone in the males. (Trans- verbenol is a principal mass aggregating pheromone in female D. ponderosae.) In all three of these Dendroctonus species volatile components of host resin, in addition to one or more pheromones, were necessary to pro- duce mass attack. In D. frontalis and D. pon- derosae the terpene a-pinene was the most effective; in D. brevicomis a-pinene, ^-pi- nene or myrcene used separately, or the lat- ter two in combination were effective in combination with pheromones (Renwick and Vite 1970, Bedard, Silverstein, Wood 1970). In contrast to that seen in Ips. D. frontalis, and apparently in other Dendroctonus spe- cies, pheromone release may commence be- fore breeding begins (Vite and Crozier 1968). In D. frontalis frontalin and frans-verbenol are released by the female immediately upon reaching the host tree. As boring commences the addition of a-pinene enhances their at- tractiveness, resulting in a mass attack in which males predominate about 3:1. As males arrive they produce verbenone, which reduces the response by other males. When the concentration of verbenone reaches a suf- ficiently high level the response of both sexes is inhibited and the attack then focuses on neighboring trees. In D. brevicomis the pat- tern is similar except that fro n.s-verbenol does not appear to have a significant function. A small amount of frontalin is also released by female D. brevicomis and is highly attractive when combined with host resin (Vite and Pit- man 1969). In D. ponderosae a-pinene at- tracts the pioneer beetles to the host. These females then produce fro ns- verbenol 12-16 hours after feeding commences, which, in combination with a-pinene, attracts large numbers of males and other females (Pitman, Vite, Kinzer, Fentiman 1968). Although the males produce brevicomin in substantial quantities, the function of this substance is not known in this species. The attraction stops when frons-verbenol and a-pinene pro- duction are discontinued (Vite and Crozier 1968). In D. pseudotsiigae the pheromone frontalin, together with the monoterpene camphene, induces mass attack on Douglas fir (Pitman and Vite 1970). Two additional components of the D. pseudotsiigae phero- mone complex have been identified, namely 20 Great Basin Naturalist Memoirs No. 6 the ketone 3-methyl-2-cyclohexen-l-one and the alcohol 3-methyl-2-eyclohexen-l-ol, but their functions in communication have not been determined (Vite, Pitman, Fentiman, and Kinzer 1972). Pheromones probably occur throughout the Scolytidae and play a vital role in the survival of species. They are an important isolating mechanism. The occurrence of vari- ous chemical substances and their biological fimction appears to follow definite patterns. A thorough knowledge of the composition of pheromones and their distribution within the family should greatly enhance our under- standing of phylogeny within the family. ECONOMIC LOSSES Ecological Role in a Primeval Forest In a primitive forest one of the greatest ob- stacles to continued growth is the recycling or removal of dead and dying plants. A slow- ing or stagnation in the removal of this mate- rial throws the entire ecosystem out of bal- ance to the great disadvantage of most organisms contained in it. The Scolytidae breed principally in imthrifty, broken, over- mature, and dying woody plants. Usually they are the first biological agents to attack these tissues. Not only do they consume the tissues of their hosts, but they introduce or provide avenues for the entry of other disease-causing or saprophytic agents that ac- celerate the deterioration of dead or dying plant material. The removal of these sup- pressed, stagnated, injured, diseased, imth- rifty, and fallen trees opens the way to more vigorous growth of the surviving plants in a healthier forest community. Host Susceptihility to Attack Trees differ significantly in their suscep- tibility to bark beetle attack depending upon their site, vigor, age, and physiology. Over a period of time these seemingly minor differ- ences in susceptibility may alter the charac- ter of a forest, at least locally, or eliminate certain tree species from marginal sites. It is generally recognized that trees grow- ing on poor sites are more vulnerable to at- tack that those growing on choice sites. A conspicuous example is seen in certain arid areas of the western United States where trees growing on chronically dry sites rarely attain maturity before being killed by bark beetles. Wet sites, near the margin of mois- ture tolerance for the species, have a similar effect in other areas. Miller and Keen (1960:155) indicate in their summary of work with Dendroctonus brevicomis that slow- growing trees are attacked more readily than vigorous trees whether they are on a poor or a good site. They also report that consid- erably more beetles are required to kill a vig- orous tree than one growing at a slower rate. In ponderosa pine fast growth, thick bark, and large heavy crowns are associated with this resistance. When there is an increase in the number of susceptible trees in a given area the bark beetle population is high; when there are few susceptible trees it is low. However, when the beetle population is high the degree of selection is reduced and pre- viously resistant trees are also killed. Under epidemic conditions they report (p. 159) a tendency for the fast-growing trees to be at- tacked, except that in any age class the first trees attacked were either suppressed, showed evidence of injury, or had deteriorat- ing crowns. Once these "key trees" were oc- cupied, the attack spread to neighboring trees regardless of size, vigor, or other factors. In view of the above. Keen (1936, Miller and Keen 1960:177) developed a system of ponderosa pine classification based on age and vigor in an effort to predict which trees were most likely to be attacked (Fig. 5). That system was replaced (Keen and Salmon 1942) by a more accurate, simplified risk rating that measured current tree health. Removal of all high risk (Class 4) trees in California did not result in greater infestation of trees in the remaining three classes (Miller and Keen 1960:187). In Oregon, only 67 percent of the predicted total volume of loss of high risk trees on a 640 acre plot were actually killed by insects over a five-year period; the remov- al of such trees resulted in a 90 percent re- duction in infestation (p. 188). It must be rec- ognized that sanitation salvage can be practiced only on well-managed forests with suitable access roads. There are also com- plicating factors that make it difficult to 1982 Introduction risk classes for ponderosa pine 21 «: M ^•■v '^ Low Risk High Risk Fig. 5. The classes of risk in ponderosa pine to western pine beetle attack. No. 1, Low risk: full, healthy foliage, vigorous crown, dark green needles long and coarse, virtually all twigs with normal foliage, no weakened areas in crown. No. 2, Moderate risk: fair to moderately healthy crowns, with some imperfect areas, needle length average or above, color fair to good, some twigs and branches lack foliage but without definite weak areas. No. .3, High risk: crown health fair to poor, ragged or thin in some areas, foliage thin in some areas, needles shorter than average, their color fair to poor, some to many twigs and branches lack foliage or are fading or dead, with small, localized areas of crown weakened. No. 4, Very high risk: crowns ragged or thin, often with active insect infestations in upper areas, foliage thin or bunchy, needles short, sparse, color poor, parts of crown weakened, twigs and branches dead in some areas, active top-killing often evident. (After Miller and Keen 1960:183.) apply the above California example to other tree species in different geographical areas. Bark beetles differ in their ability to toler- ate tree resins (Smith 1963). Individual trees also differ in the monoterpene composition of their resins (Smith 1966). In addition. Smith (1964) demonstrated that ponderosa pine trees being attacked by Dendroctonus brevi- comis differed significantly in monoterpene content from neighboring trees not attacked by this species. From these and other data it is evident that host resistance to insect attack can be improved through plant breeding. Sig- nificant developments in this field are ex- pected in the near future. Competition for Food Other kinds of insects, in addition to Scoly- tidae and Platyodidae, feed upon the tissues of woody plants. Because of their small size and limited ability to cope with the altered microenvironment, bark and ambrosia beetles usually do poorly in competition involving robbery of the food source. Most species avoid conflicts by being the first to infest the unthrifty or dying tissue and rear their broods before the eggs of competitors hatch. Those scolytids with long life cycles and those arriv- ing late at the host commonly experience dif- ficulty in completing their development 22 Great Basin Naturalist Memoirs No. 6 without being subjected to the starvation or physical disruption that results from competition. Round-headed borers (Cerambycidae) and flat-headed borers (Buprestidae) are the fami- lies of greatest concern. When abundant, lar- vae of these families may remove up to 75 to 95 percent of the phloem of a given tree (Blackman 1931:52). These larvae usually are considerably larger and live much longer than do the scolytids. When they encounter scolytid tunnels they consume all phloem tis- sues without deviating from their course and thereby destroy the occupants. Those that do escape often are unable to complete their de- velopment due to the changed phloem ecology. Another kind of competition results from overcrowding by members of the same spe- cies. In most phloeophagous scolytid species the larval mines are independent of one an- other and never cross except imder unusual circumstances. Often, when crowding is ex- treme, tunnels of larvae near maturity merge or cross and one is usually killed by the other. When young larvae are involved it is not un- common for some of them to die in their sep- arate individual mines without apparent cause. The resulting mortality benefits the to- tal population by permitting at least part of them to attain maturity. Several scolytid species, including Car- pJwhius arizonicus Blackman, many Micraci- sella species, and other twig beetles often breed most commonly in small branches gird- led by Cerambycidae. In most of these in- stances the scolytids complete their life cycle and emerge before the cerambycid larvae be- come large enough to be a factor in scolytid survival. Relation to Fire, Slash, AND Natural Disasters Fire.— When properly controlled, fire has long been used in maintaining certain types of forest growth and it has been used to con- trol and destroy broods in bark beetle in- fested trees. Fire of sufficient intensity will destroy broods under the thin bark of some trees without burning the bark of the infested tree. Uninfested trees may be sufficiently dehydrated by the heat that their tissues are unsatisfactory for brood development. How- ever, trees slightly injured by fire that ordina- rily would recover from their injury often are highly attractive to bark beetle attack and may serve as the focal point of a developing epidemic. Broods in infested trees with thick bark are rarely injured by fire unless the bark is burned from the trees (Miller and Keen 1960:220). Bark beetle species react differently to fire. Dendroctonus ponderosae and D. valens are reported to attack fire-injured trees almost immediately after the bum, but D. brevi- comis is not attracted to the burn but concen- trates on surrounding trees a year or two af- ter the burn (Miller and Keen 1960:220, etc.). Certain buprestids and cerambycids that nor- mally breed in drier tissues than do scolytids are much more abundant in fire-injured trees. In most instances, D. pseudotsugae is depen- dent for population buildup upon slash and trees that are windfallen, fire-injured, or damaged by other natural disasters. In Tilla- mook County, Oregon, a major fire in 1933 resulted in the loss of 200 million board feet of Douglas fir during the following three- year period due to D. pseudotsugae (Cham- berlin 1939:83, Bedard 1950). Following epidemics in which Dendroc- tonus beetles kill substantial numbers of trees, these dead snags constitute a forest hazard in the event that a fire occurs in the area. The presence of such trees greatly en- hances the speed and intensity of the fire, making them a factor to be considered in for- est protection. Slash.— Numerous species of insects, par- ticularly bark and ambrosia beetles, breed in slash, cull trees, logs, and stumps. Most of those species breed only in slash and other dead material and are of no economic con- cern other than that they accelerate the dete- rioration of this dead plant material. In the larger material, however, they can create a definite problem in some areas. Dendroc- tonus rufipennis, D. pseudotsugae, D. mur- rayanae Hopkins, and, to a lesser extent, other species in this genus and most species of Ips normally breed in this material. Epi- demics of these species, whether due to indi- vidual species or combinations of them, com- monly are traced to an initial population 1982 Introduction 23 buildup in slash, stiuups, and windfalls. The insects then turn to green timber when the supply of dying material is exhausted (Cham- berlin 193'9:84, Craighead 1927, Graham 1922, Hopping 1915, Patterson 1927). In the tropical and subtropical areas of the world the most serious timber losses to in- sects result from the boring of ambrosia bee- tles {Xyleborus, Monarthntm, and Platypo- didae) in logs either in the forest, in decking areas, or at the mill. Similar damage occurs in Oregon, Washington, and British Colum- bia by Trypodendron lineatum and Gnatho- trichus spp. In the tropics swarms of ambrosia beetles often hover about while waiting for a tree being cut to fall and begin boring in be- fore it is cut into logs. It is not uncommon for the sapwood to be so heavily infested that it is entirely discarded when the logs reach the mill. Populations of these ambrosia beetle species usually build up in small trees de- stroyed by logging road construction before felling begins, and in slash thereafter. Occa- sionally populations reach a level where green timber is killed, but such attacks are limited and of short duration; epidemics in green timber do not develop. Although statis- tics on losses in the American tropics do not exist, one major operator at Barinas, Vene- zuela, indicated that one-fourth to one-third of the total volume of logs reaching his mill was discarded due to ambrosia beetle damage by Xyleborus ferrugineus (Fabricius), X. af- finis Eichhoff, X. volvulus (Fabricius), and Platypus parallelus (Fabricius). Natural disasters.— During severe thun- derstorms, lightning may strike trees. These injured trees are favored breeding sites of several Dendroctonus and Ips species and may serve as a center from which epidemics develop. It is much more common for severe local winds to blow down large numbers of mature trees in which populations build up then move to green timber. Relationships with Fungi and Disease Based upon numerous field observations and a few laboratory tests, it is apparent that most, if not all, Scolytidae are associated with fungi. The relationships evidently range from the most casual, or perhaps accidental, con- tact to intimate mutualistic bonds in which neither the fungus nor the beetle could sur- vive without the other. Some phloeophagous bark beetles, particu- larly such genera as Carphoborus, Chae- tophloeus, and others that live in rather dry tissue, show little or no evidence of associ- ation with fungi. In other phloeophagous spe- cies and virtually all xylophagous forms, such as Dendrosinus, Hylocurus, Micracis, Phloeo- boriis, and Thysanoes, the tissues in the im- mediate vicinity of the tunnels are either dis- colored or in a state of decay far in excess of that found a few millimeters from the tun- nels. It is suspected that the nutritional value of xylem is so low that fungi are required to modify it or synthesize other products from it before it can be used as a food source. In ad- dition to those scolytids that use the host tis- sues as the primary food source, a composite assemblage of unrelated groups of ambrosia beetles culture fungi on their tunnel walls and use the spores as their primary food. Bramble and Hoist (1940) report that the fungus infestation in trees attacked by Den- droctonus frontalis Zimmermann includes a complex of species. The primary invasion tliat interferes with transpiration and kills the tree is by Dacryomyces sp. and Zygosac- charomyces pini. Later, Ceratocystis pint takes the lead in infesting the deeper sap- wood and staining it blue to black. Tricho- dertna lignorum and Monilia spp. are present, but apparently are secondary invaders of host tissue. These blue stain fungi discolor infested wood, thereby reducing its value, but not its structural quality (Francke-Grosmann 1963). Ceratocystis ips, associated with Ips calli- graphus (Germar), /. pini (Say), and 7. avulsus (Eichhoff), has a similar effect on pine, as does Trichosporium symbioticum (brown stain), carried by Scolytus ventralis LeConte on Abies concolor. Graham (1967) reviews the mutualistic relationships between fimgi and scolytidae and lists the various genera involved. The blue stain fungi are transported in spe- cial integumental sacs, termed mycetangia, by the female beetle. They are inoculated into living host tissue soon after the tunnels reach the cambium region. The mycelium grows very rapidly and interferes with the plant's transpiration. Although there may be some blockage of conducting vessels, other 24 Great Basin Naturalist Memoirs No. 6 Fig. 6. Oral mycetangia of a female Dryocoetes con- fusus; b, brain; fs, fiingiis spores; ms, niycetangial setae; my, mycetangia. (After Farris 1969:528.) factors are involved that result in tlie rapid death of the host. This reaction in Ulmus to Ceratocystis idmi (transmitted by Scolytus multistriatus (Marsham)) is known as Dutch Elm Disease, and the reaction of Theohroma cacao to C. fimhriata (transmitted by Xijle- bonis ferrugineus, etc.) is the wilt disease of cacao. These and other Ceratocystis species are associated with a wide variety of other bark and ambrosia beetles {Hyhirgops, Hy- lurgopinus, Orthotomicus, Xyleborus, Trypo- dendron, Gnathotrichus) and produce some- what similar effects on other plant species. The scolytids' transmission of spores of their symbiotic fungi to their host is not a simple mechanical process. In many instances the spores are incapable of germination until thev have passed through a definite period of maturation, which may include proliferation within the body of the beetle. As might be expected in any mutualistic relationship that has reached this level of dependency, the beetles have developed inflections of the body wall into which special glands discharge their nutrient secretions, where the spores are protected and preserved (Francke- Grosmann 1963). These mycetangia appar- ently have taxonomic significance relative to their location on the body and other features. Tliey have been classified as: 1. Oral mycetangia.— Saclike pockets at the base of the mandibles beneath the epipharynx that open into the pre-oral cav- ity. They have been reported in Dryocoetes confusus Swaine (Fig. 6), Xyleborus affinis, X. andamanensis Blandford, X. fornicatus Eichhoff, and X. vekitus Sampson. 2. Pronotal mycetangia.— Saclike in- vaginations on the pronotum occur in Dac- tylopalpns and Scolytoplatypus and in nu- merous Platypodidae. 3. Prothoracic-pleural mycetangia.— These are saclike invaginations in the pro- pleural area of the female. In Trypodendron (Fig. 7) and Xyloterinus they occur near the posterior margin; in Bothrosternus and Phloeoborus they are near the anterior mar- gin; in Dendroctontis brevicomis, D. frontalis, and allied species they open at the anterior margin in the cervical membrane. 4. Prosternal-subcoxal mycetangia.— The coxal cavities have enlarged areas (Fig. 8) where spores proliferate in Gnathotrichus retusus (LeConte), G. sulcatus (LeConte), Monarthrum niali (Fitch), and M. fasciatuin (Say). From superficial examination it ap- pears that all xylomycetophagous Corthylini have similar mycetangia. 5. Pro-mesonotal mycetangia.— a pair of invaginations in the intersegmental mem- brane may be (a) overlapped by and extended beneath the posterior area of the pronotum, as in Xylosandrus gennanus (Blandford); (b) curved so as to lie beneath the anterior part of the mesonotum, as in Xyleborus dispar (Fig. 9); or (c) the mesonotum may be 1982 Introduction 25 Fig. 7.— Prothoracic pleural inycetangia of a female Trijpodendron lincatuin: Co, procoxa; Dr, mycetangium; Md, orifice of invcetangium. (After Francke-Grosmann 1956:117.) involuted to form a spiral mycetangium, as in Eccoptopterus spinosiis (Olivier). 6. Elytr\l mycetangia.— a cavity in the anterior margin of the elytra near the scutel- lum, which is supported by a cluster of setae surrounding the cavity, occurs in Xyleborinus saxeseni (Ratzeburg) (Fig. 10) and, apparent- ly, in all other representatives of that genus. Introduced Species The geographical distributions of animal species are not constant, but expand or con- tract in response to various natural fluctua- tions in the environment. In addition, inter- action between species may offer unexpected opportunities for range expansion. For ex- ample, human commerce has had a con- spicuous effect on the distribution of many Scolytidae (Marchant and Borden 1976). The extent to which commerce has affected the North and Central American fauna is summa- rized by Wood (1977). Thirty-seven species were introduced to North and Central America and established as breeding populations from an Old World source (Table 3). Of these, 7 were of Fig. 8. Prosternal-subcoxal mycetangia of female Monarthrum scutellare. (.^fter Farris 1965:31.) European origin, 13 were from Africa, and 18 were from southeast Asia (including In- donesia and neighboring islands). It is of in- terest that 31 of the 37 can reproduce by fac- ultative arrhenotocic parthenogenesis, a means by which an immated female can es- tablish a breeding population. Only two of these 37 are known to have been introduced more than 100 years ago. Of the 6 bisexual species, 4 were introduced more than 100 years ago. Of 25 North of Central American species that have extended their ranges within or beyond this area (including the adjacent is- lands), 17 of them have reached areas in the Old World (including Hawaii). Of these 17, 11 can reproduce by facultative arrhenotocic parthenogenesis. It is not known that any of these 25 reached a non-American area (or Hawaii) prior to 1900. Only 3 of the 8 spe- cies that have extended their ranges in Amer- ica, but have not reached an area outside the Western Hemisphere, have this reproductive habit. 26 Great Basin Naturalist Memoirs No. 6 Fig. 9. Promesonotal mycetangiuiii of female A'l/fe- borus dispar. I, pronotiiin; II, scutellmn; III, iiietano- tum; e, elytra; is, mycetangium; d, inycetangial gland; pd, spores in mycetangium. (After Francke-Grosmann 1956:288.) It is apparent from the above that many bark and ambrosia beetles have extended their ranges through commerce and that Fig. 10. Elytral mycetangium of female Xylehorituts saxeseni: I, pronotum; II, scutellum; III, metanotum; e. elytra; d, mycetangial gland; pd, spores in mycetangium. (Aiter Francke-Grosmann 1956:290.) those species having the facultative arrheno- tocic parthenogenesis reproductive habit are most likely to successfully establish extra- territorial breeding populations. Table 1. Breeding populations of Scolytidae introduced into .\orth or Central .America from a non-.\merican ori- gin. The species are listed alphabetically. Species Origin Introduced to Coccotrypes acictilatus Coccotrypes adiinui Coccotrypes car))(>phagus Coccotrypes dactyliperda Coccotrypes di^tinctus Coccotrypes cyperi Coccotrypes rliizopliorae Crypturgus pitsilltts Ilylastiniis ohscurus llypocryplidltts mangifcrae HypotJienemus aecpudiclavatus Ihipothenernus africanus llypothenemus areccae llypothenemiis hirmanus llypothenemus brunneus Hypothenemus ccdifornicus Hypothenemus cohtmbi Hypothenemus rrtidiae Hypothenemus cylindricus Hypothenemus erectus Hypothenemus hampei Hypothenemus javanus Hypothenem us setosus Premnohius cavipennis Premnobius ambitiosus Scolytus nudi Scohjtus multistriatus Scohjtus rugulosus Xyleborinus saxeseni Xyleborus dispar Xyleborus fornicatus Xyleborus rubricoUis Xyleborus validus Xylosandrus compactus Xylosandrus crassiuscidus Xylosandrus gemumus Xylosandrus morigerus New Guinea SE Asia, Indonesia .Africa? Africa? Ceylon? SE .Asia Indonesia Europe, Asia Europe India Indonesia S Africa SE Asia SE .Asia Africa? Africa? Africa? SE Asia? Africa? Africa? .Africa Africa? Africa? Africa Africa Europe Europe Europe Europe Europe SE Asia SE Asia SE Asia SE Asia SE Asia Japan SE .Asia Panama, Brazil Florida (?) to Brazil Florida to S America US.A to S .America Florida to S America Florida to S .America Florida, Galapagos Islands E North America Canada, USA Florida to S .America Honduras, Jamaica USA to S America Florida to S .America Florida to C .America USA to Trinidad US.A to Mexico USA to S America USA to S America Mexico to S America US.A to S .America C, S .America Florida to S America Mexico to S .America Florida to S .America (C?) S .America E North America N America N, S .America N, S America N America Panama E North .America New York Florida, S .America South Carolina, Hawaii E North .America Mexico to S America 1982 Introduction 27 Table 2. Breeding populations of North and Central American Scolytidae that have extended their ranges in America or have been exported to an Old World area. The species are listed alphabetically. Species Origin Exported to Araptus politiis Corthijlus spinifcr Cryphdlomorpfms jalapae Cryptocarenua heveae Cryptocarenus seriatus Dcmlroctontts frontalis Gruithotrichtis materiarius Hiiplithenemtts eruditus Hyphtheneinus obscurus Hyphthenemus paraUelus Htiphthcnemus puhescens Hi/phthenem us seriatus Ips gmndicollis Micruhortts boops Pagiocerus frontalis Phloeosintts cupressi Pliheosintis serratus Pityophthoriis jiiglandLs Xyleubrinus aspericauda Xylebonts af finis Xyleborits ferrugineus Xylebonts obliquus Xyleborus spinulosits Xyleborus volvulus Xyleborus xylographus Mexico, C America C, northern S America Mexico C, S .America S America USA USA Tropical America? Tropical America Mexico Tropical America? Tropical America? N America C America S America California WUSA Arizona C, S America Tropical America Tropical America Puerto Rico? Tropical America Tropical America Eastern N America Florida, Antilles Florida, Brazil Worldwide (ephemeral) Florida, .\frica Florida, .Antilles Honduras Europe .Almost worldwide Intercepted worldwide Hawaii Florida, Hawaii USA, Africa, etc. Australia .Africa, Jamaica SE USA Panama, .Australia Jamaica California? Florida Africa, Hawaii to Malaya .Africa, Hawaii to .Australia USA, Africa Hawaii Africa, Hawaii to Malaya California Control Losses Attributed to Scolytidae In a natural forest the Scolytidae perform a vital role in the maintenance of vigorous growth and in the recycling of dead plant tis- sue. However, their activities come in direct conflict with man when he diverts forest products for use in his economic or cultural system. The economic effect of Scolytidae ranges from beneficial values to enormous economic loss. Those species that confine their attacks to shaded-out branches on living trees, such as Carphoborus, Pityoborus, some Pityoph- thortis, etc., accelerate a natural pruning pro- cess that is usually beneficial to vigorous tree growth and reduces the fire hazard. Natural thinning of suppressed, wind-thrown, broken, and injured trees also tends to be beneficial in a similar manner except in those cases where such material can be removed and uti- lized; Pityophthorus, Xylechinus, Pseudohyle- sinus, Pityogenes, some Ips, and various am- brosia beetles are the principal genera involved in a coniferous forest. Such species become an economic problem when com- mercial logs are attacked. The destruction of cones in Pinus by Conophthorus is of margin- al importance unless rapid reproduction or other use of seed is important. The destruc- tion or injury of living twigs in Pinus by cer- tain Pityophthorus, etc., may have a com- paratively unimportant stunting effect on growth, but, more importantly, they may weaken the trees sufficiently to make them vulnerable to aggressive tree-killing species and may transmit plant diseases. The major conflict between scolytid activity and human interests is directed in a natural coniferous forest at the removal of overmature trees or stagnated growth and involves mostly Den- droctonus and Ips species. In deciduous and tropical forests very different conditions pre- vail. The transmission of disease (Dutch Elm Disease, etc.) or the activities of ambrosia beetles in logs may cause the principal eco- nomic effect. The actual monetary loss caused by bark and ambrosia beetles is unknown. Tree mor- tality caused by bark beetles in North Ameri- ca probably exceeds that of all other agents combined, including fire (Massey 1974). 28 Great Basin Naturalist Memoirs No. 6 Values given in the literature vary from au- thor to author and probably are not entirely reliable; however, there is some agreement on the most destnictive forms. It is estimated that Dendroctonus brcvicotnis destroys an av- erage of more than two billion board feet of standing timber each year; D. ponderosae, D. rufipennis, D. frontalis, and perhaps D. pseu- dotsugae each average about one-half billion board feet annually. Other Dendroctonus, Scohjtus, and Ips species inflict lesser but sig- nificant losses in coniferous forests. No mea- sure of losses to fruit trees by Scohjtus rugu- losus, to elm trees by S. multistriatus, to forage crops by Hy last inns obscurus, to orna- mental and horticultural plants by Xylo- sandrus compactus, or to coffee by Hypo- thenemus hampei has been attempted, but the value is immense. Less spectacular losses caused by numerous other species in the tem- perate region could be cited. Economic loss caused by scolytids in tropi- cal areas is usually less spectacular and not as easily measured as in temperate areas. It in- cludes the destruction of commercial logs within days after they are cut, by ambrosia beetles; the destruction of seeds and fruits by seed borers; the transmission of disease, such as the wilt disease of cacao, by ambrosia bee- tles; and the reduction of growth and produc- tivity by twig borers, etc., at much more in- tensive rates and on a scale not seen in northern areas. Mass attacks on healthy trees are virtually unknown. The damage is much more subtle and difficult to assess. Natural Control Bark and ambrosia beetle populations in nature fluctuate enormously from one season to another and from year to year. These fluc- tuations may be correlated with life cycle, with biological opportunity, or with other factors inherent in the population or in the environment. All organisms have the capaci- ty to reproduce at a rate greater than is nec- essary to perpetuate the race. If any species were to reproduce at its maximum potential rate, it would completely destroy its food supply and severely disrupt the biotic com- numity in which it lives after only a very few generations. Natural factors within the com- munity counteract the biotic potential to maintain populations at a more or less con- stant but fluctuating level. Factors such as climate, weather, health and vigor of the host population, and natural disasters have a significant effect on insect populations and, at times, have a controlling effect on them. In addition, biotic factors have a more subtle, but often a more con- stant and significant effect in reducing or controlling populations. These factors include insect parasites and predators, predaceous mites, insectivorous vertebrate animals, nematode parasites, and disease. A prime ob- jective in forest management should be the encouragement of these indigenous enemies in order to reduce the length and intensity of bark beetle epidemics or, possibly, to prevent them from developing. In some instances they have destroyed more than 90 percent of the bark beetle brood in a given generation. Insect parasites.— Various species of Lonchaeidae (Diptera) are found in bark beetle tunnels and are regarded as parasites (technically they actually may be predators). Among the Hymenoptera, the families Brachonidae {Atanycolimorpha, Atanycolus, Bracon, CaUihonnius, Cenocoelius, Chelonus, Coeloides, Colastes, Cosmophorus, Crypto- xilos, Dendrosoter, Doryctes, Ecphylus, Eu- badizon, Glyptodoryctes, Helconidea, Hetero- spiJus, Opius, Orgilus, Paraecphylus, Russellella, Spathius, Triaspis, Vipio), Beth- ylidae {Cephalonomia, Scleroderma), Chalci- dadae {Trigonura, Perniphora), Diapriidae (Cinetus), Encyrtidae (Microterys), Eulo- phidae {Entedon, Pediobius, Tetrastichus), Eupelmidae {Eupelmus, Eusandulum, Meta- pelma), Eurytomidae (Eunjtoma, Ipideury- toma), Gasteruptiidae {Antaeus), Ichneumo- nidae {Aplomerus, Campoplex, Doliclumiitus, Gambrus, Gelis, Helcostizus, Neoxorides, Odontocolon, Xorides), Mymaridae {Ooc- tonus, Polynema), Podagrionidae (Euchrysia), Proctotnipidae (Cryptoserphus), Pteroma- lidae {Aceroce})Jiala, Amblymerus, Caudonia, Cecidostiba, Cheiropachus, Coelopisthia, Dipachystegma, Elachertodomyia, Ha- brocytus, Halicoptera, Heydenia, Hypoptero- malus, Psilocera, Psilonotus, Pteromalus, Rhaphitelus, Rhopalicus, Theocolaxia, Tomi- cobia), and Torymidae {Liodontomerus, Rop- trocerus) were listed by Bushing (1965) as containing species parasitic on Scolytidae. 1982 Introduction 29 The Pteromalidae genus Karpinskiella is unique in that it parasitizes adult scolytids. Coeloides dendroctoni Cushnian (Bracho- nidae), an important parasite of Dendroc- tontis ponderosae in Montana and Washing- ton is selected as an example of the parasitic Hymenoptera. The mated adult female wasp flies to a tree attacked the previous August where the host scolytid larvae are now about half grown (DeLeon 1935a). As she crawls over the surface she uses her antennae to de- tect the movement of a larvae. Once a larva is located she positions herself on the bark then inserts her ovipositor in the bark, pierces the larval cuticle, then deposits one egg on the surface of the larva. The egg hatches in 1 to 4 days by which time the host larva becomes inactive and appears para- Ivzed (apparently the result of something in- troduced by the female parent). The newly hatched parasite crawls over the surface of the paralyzed host until it finds a suitable place to feed. It then punctures the host cut- icle and sucks up the fluid that exudes. Growth requires about 10 days. The pupal cocoon may be spun immediately after growth is completed or it may be delayed up to 60 days. The pupal stage may require about two weeks or it may serve as the over- wintering stage. Two to two and one-half generations per year may occur, with three principal periods of emergence distributed from late Mav to late August (DeLeon 1935a). Insect predators.— The coleopterous families Cleridae, Colydiidae, Cucujidae, Elateridae, Histeridae, Nitidulidae, Rhi- zophagidae, Staphylinidae, and Trogositidae are reported by Chamberlin (1939) as major predators of Scolytidae. The Othniidae and the genus Hijpophloeiis of Tenebrionidae may also fimction as important predators. The dipterous genus Medetera (Dolichopo- didae) is an unusually important predator during its larval stage. The adults of Medetera aldrichii Wheeler tend to congregate on the surface of trees recently attacked by Den- droctonus ponderosae (DeLeon 1935b). The females place single or small clusters of eggs under small scales of bark on the surface of the trees. In 10 to 14 days the eggs hatch and the young larvae move to the inner bark, where they feed on eggs, larvae, and pupae of the host. Other small insects are also ac- ceptable prey. The larval period apparently may vary from 1 to 11 months. Pupation oc- curs in a silken cocoon beneath the bark and requires about 14 to 17 days. Adults appar- ently emerge through beetle exit holes, cracks in the bark, etc. It was estimated by DeLeon (1935b) that 40 to 50 percent of the bark beetle brood was killed by this species in Montana and Washington. Many other predaceous insects may prey upon adult bark beetles during the flight pe- riod and some may significantly reduce pop- ulations. For example, a heavy attack by Xyleborus spathipennis Eichhoff in Costa Rica was virtually eliminated by ants as the beetles attempted to begin new galleries (pers. obs. 1966). Mite predators.— The extent to which mites prey upon scolytids is not fully known. Moser and Roton (1971) reported 96 species of mites associated with Dendroctonus fron- talis, of which 3 {Iponemus, Tarsonemidae) are known predators and several others are suspected predators. Lindquist (1969) re- viewed 18 species of Iponemus, 16 of which are considered egg parasites of Scolytidae. Kielczewski (1976) reported more than 170 species of mites associated with 57 species of bark beetles in Poland; the ecological role of most of them is not yet known. Many of the mites are phoretic and are carried from one host to another by the beetles. Female Iponemus mites are phoretic on the emerging brood of the bark beetle tribe Ipini. In the new tunnel the previously mated mite leaves the beetle and crawls along the egg gallery until it locates a niche containing a newly deposited egg. The mite enters the niche and the beetle seals it in with the egg with a plug of tightly packed frass. It appar- ently is not possible for a mite to enter an egg niche after the frass plug is in position. After piercing the cuticle of the egg, the mite engorges on its contents, causing her idio- soma to swell into a sphere. Engorgement continues until the sphere is approximately equal in size to the host egg (about 0.5 mm). About two davs later egg laying commences and continues for several days. Her body then turns dark, becomes flaccid, and dies. Ap- proximately 40 to 80 eggs may be produced by each mite; these usually form a clu-ster 30 Great Basin Naturalist Memoirs No. 6 about her body. The mite larvae emerging from the eggs apparently require no food and rarely move. The larvae, slightly larger than the unengorged parent, apparently derive energy from the fat content of their own bodies. They pass into an inactive, turgid "pupal" stage without molting, from which they emerge as adult mites. Males emerge first and mate with females as they emerge. The females are very active and disperse from the maternal sphere after mating. About two weeks are required for development. Insectivorous vertebrates.— Of the for- est birds, woodpeckers stand alone as the im- portant predators of bark beetles. They are particularly conspicuous during epidemics, where they have been reported to destroy up to 75 percent of the beetle population (Mas- sey and Wygant 1954:18). Their feeding ac- tivity accelerated drying of the bark and re- sulted in the mortality of far more bark beetles than were eaten. Miller and Keen (1960:92) report the reduction of a Dendroc- tonus brevicomis population in California on ponderosa pine of 73 percent and in Oregon of 72 percent on trees heavily worked by woodpeckers; however, only a small percent of the infested trees were heavily worked by woodpeckers. Amphibians, reptiles, and mammals (par- ticularly rodents) will feed voraciously on bark beetles and their larvae when the bark is peeled from a tree. Under normal circum- stances, however, they feed on them only in- cidentally during the flight period except for those species {Ips, Tnjpodendron) that over- winter on the forest floor. Nematode parasites.— Massey (1974) summarized the biology and taxonomy of nematode parasites associated with bark bee- tles. Of 33 species of beetles examined in quantity, 31 were infested by nematodes. He found that the rate of infestation varied with- in any population (0 to 90 percent) and fluc- tuated in a given area from one year to an- other (15 to 80 percent). The reasons for the fluctuations are not known. A majority of the nematodes are carried from one host to an- other beneath the wing covers, in the inter- segmental folds of the abdomen, and on the tarsal and tibial joints of the legs. Most of them are obligate parasites and usually do not kill the host. The nematodes are either oviparous or ovoviviparous. Immature stages are deposited in the beetle egg galleries by infested beetles. Males develop to maturity in the tunnels and impregnate immature free-living females. Immediately after mating the impregnated females penetrate the cuticle and enter the body cavity of the host, which is a larva in about the second instar. Eggs or larvae are released into the body cavity, following which the young larvae penetrate the gut and are then eliminated with the fecal mate- rial. The nematode life cycle is usually syn- chronized with that of the host, so both at- tain maturity at about the same time. Diseases.— Although many viruses or polyhedral diseases are known for insects, none have been studied in the Scolytidae. Numerous fungal organisms, some of which may be pathogenic, have been observed on scolytids, but their effect on a population is unknown. Applied Control A forest is a living, dynamic community that may change dramatically in response to fluctuations and modifications of environ- mental factors. As indicated previously, in a natural forest bark and ambrosia beetles play an important role in maintaining the health and vigor of the trees by removing stagnated growth and by accelerating the recycling of dead material. Because their natural function in a managed forest usually conflicts with hu- man interests, however, they are transformed from a beneficial to a destructive element. As such, they are regarded in North America as the most destructive natural biotic factor to standing timber in a managed forest, exceed- ing the combined total of all other factors, in- cluding fire, by a wide margin (Massey 1954). A tree that has been attacked by bark beetles usually cannot be saved. Control by management.— It must be as- sumed that endemic populations of bark and ambrosia beetles are always present in a for- est. Since, under endemic conditions, the bee- tles breed in unthrifty, injured, broken, wind thrown, or felled material, means must be found to maintain the health and vigor of the 1982 Introduction 31 stand if damage is to be reduced or avoided. Vigor might be restored to stagnated young stands by a solution as simple as thinning or to older stands by the removal of overmature trees. In other situations the problem may be much more complex and appropriate action may require extensive knowledge of the ecol- ogy and population dynamics of the beetle species as well as of the climate, weather, site, and other factors. In ponderosa pine forests in western North America, Dendroctoniis brevicomis is the principal destmctive species. Under endemic conditions it breeds in unthrifty or injured standing trees; it rarely breeds in down mate- rial unless it is elevated well above the ground. With this knowledge Keen (1936) analyzed age and vigor tree groups and de- veloped a risk rating technique that made it possible to identify with reasonable accuracy those trees that would be attacked by the beetles (Fig. 5). The removal of the high risk trees in a managed area reduced remarkably both the frequency and intensity of epidem- ics. Epidemics that followed were triggered by prolonged drought or other uncontrollable factors (Miller and Keen 1960). Similarly, Dendroctoniis pseudotsugae is the principal destructive species in Douglas fir in western North America. Endemic pop- ulations breed in broken, wind thrown, or felled trees (Rudinsky 1966). Removal of these susceptible trees generally prevented the development of an epidemic. The habits of D. rufipennis in spruce are apparently similar (Massey and Wygant 1954), and sim- ilar results are obtained with sanitation sal- vage (Schmid 1977). The removal of potential breeding mate- rial from a forest, orchard, or isolated orna- mental tree to lessen or eliminate bark or am- brosia beetle attack is applicable to almost any host or geographical situation. The prac- tice in some circumstances may become more effective if the material is allowed to become infested before it is removed. How- ever, in order for this latter technique to be effective, greater knowledge of the habits and behavior of the insects is required and thorough destruction of infested materials must be assured or the intended control coidd lead to a disastrous epidemic. Surveys.— Losses caused by bark beetles usually involve individual trees or clusters of trees irregularly distributed in the forest. Be- cause forests contain vast acreages of trees from which economic return is minimal, in- sect surveys are made to locate infestations in their early stages, to appraise their potential destructiveness, and to determine the need for direct control. They are used to diagnose and to predict the economic impact a devel- oping epidemic might have. The results pro- vide information useful in direct control and also contribute to our understanding of these insects in nature. In evaluating populations it is important to know whether an endemic or an epidemic condition exists and, if epidemic, whether the population is increasing or decreasing. En- demic conditions prevail when natural con- trol factors (climate, weather, predators, par- asites, di.sease) hold the population at a more or less constant level at which damage is nor- mal. Epidemic conditions exist when damage exceeds normal limits. With Dendroctoniis brevicomis, endemic losses are those equal to less than annual tree growth, epidemic when losses exceed annual growth. Bark beetle surveys are of two kinds. First, detection surveys locate potential epidemics or locate newly established foreign species and establish changes in their distributions; accurate identification of the species encoun- tered may be all that is required. Second, evaluation surveys determine (a) the extent and intensity of the infestation, (b) infestation trends, (c) current and expected damage, (d) need for direct control, and (e) effectiveness of direct control. Evaluations are made di- rectly by measuring the quantity and vigor of the beetle population or indirectly by mea- suring tree mortality or other damage caused by the beetles. Because of the ease with which it is measured, damage has been ased much more commonly in the past, but cur rently population trends are considered a more reliable indicator in assessing the need for control. Conditions that trigger epidem- ics, such as wind throw, are also assessed. Both aerial and ground surveys may be used. Aerial surveys usually require less time, effort, and expense. They may be made visu- ally or with the aid of photography, using various types of film or lens filters that 32 Great Basin Naturalist Memoirs No. 6 accentuate features of dead and unthrifty trees (based on the amount of heat radiated). Ae- rial surveys are usually supplemented by ground surveys when irregularities or sus- pected embryonic epidemics are encoun- tered. Aerial photographs may make possible the detection of infested trees not recogniz- able to the unaided eye that can then be lo- cated and examined during a ground survey. They also accelerate the speed and efficiency with which ground surveys can be carried out and provide a permanent record which can be reexamined later. Direct control.— Most of the bark beetle control applied in American forests is di- rected at members of the genus Dendroc- tonus. The first attempt involved D. ponde- rosae in the Black Hills of South Dakota in 1906. Direct control refers to any attempt to reduce populations by artificial means. Its objective is to reduce bark beetle populations to a point where economic damage is reduc- ed or eliminated. It is used as a last resort when natural and cultural control fail. Surveys provide the biological and eco- nomic data on which direct control decisions are based. First, they identify the insect as one capable of posing an economic threat. Second, they determine that the stand is composed of species and age classes that might sustain an epidemic in trees of eco- nomic value or that might threaten an adja- cent area of economic worth. Third, they de- termine whether the insect is endemic or epidemic and, if epidemic, whether the trend is up or down. A decision relative to the ne- cessity for direct control and the methods and extent to which it will be carried out are based on these data. Several methods of direct control have been used successfully to reduce bark beetle poulations. The method selected depends upon (a) the habits of the beetle, (b) the thickness of bark, (c) the size of the infested trees, (d) the height of the infestation, (e) the forest type, (f) the accessibility to roads, and (g) public pressure. These methods include the following (summarized from Rudinskv 1960, 1978). ' 1. Scdvage: Infested trees are felled and re- moved from the forest before brood matures. To be successful, access roads are essential and the infested material must be removed beyond the flight range of the beetle or else the bark and outer slabs must be treated or destroyed. The expense of a salvage oper- ation usually far exceeds the value of the sal- vaged timber. 2. Fell, peel, burn: This is the oldest meth- od of direct control. It is still in use in areas where chemical control is not feasible. In- fested trees are felled, the upper infested bark is peeled then piled along the trunk and fired. It is used particularly in those species where the brood is not exposed on peeled bark at the time the operation is carried out, such as Dendroctonus brevicomis. The cost of this method is comparatively high ($4.40 per tree for 62,437 trees, according to Keen 1952). 3. Fell, deck, burn: Infested trees are felled, piled in layers that alternate at right angles in direction, then fired. The method is used when infested trees are comparatively small, such as with Dendroctonus ponderosae in lodgepole pine. Care must be taken to po- sition fires in open areas where healthy trees will not be scorched, thereby making them susceptible to beetle attack. It may also be necessary to treat the stumps of felled trees to prevent a population buildup in them. The cost per tree is about half that of the fell, peel, burn method. 4. OU burning: This method was devel- oped to treat thin-barked standing trees, such as Dendroctonus ponderosae in lodgepole pine. The infested bark on the bole of stand- ing trees is sprayed with slow-burning fuel oil and fired. Because of the limitations of spray equipment, tall trees must be felled for effec- tive treatment of the upper bole. Great care must be exercised to avoid scorching green trees. Careless treatment can precipitate a greater epidemic than the one being treated. Keen (1952) reported the cost of treatment per tree at $0.68 to $1.05. 5. Peeling: The infested bark of either standing or felled trees is peeled to expose broods to desiccation and to predation by ro- dents, ants, etc. It is effective only when the brood is exposed on peeled bark, such as with Dendroctonus ponderosae and D. pseudotsugae. 6. Solar-heat: The infested trees are felled, limbs are removed, and the log is positioned so as to receive maximum radiation from the 1982 Introduction 33 sun. In areas where air temperature exceeds 24-26 C (75-78 F), subcortical temperature exceeds 43-51 C (110-123 F), which is lethal to bark beetle larvae (see High Temperature luider Hibernation and Estivation, above). Logs must be turned after exposure for sever- al days for the temperature to reach lethal levels on all surfaces. This method was used successfully on Dendroctonus ponderosae on lodgepole pine. 7. Trap trees: Freshly felled or girdled standing trees may attract bark beetles to a treatment area, where their destruction is carried out. This method met with limited success when applied to Dendroctonus rtifi- pennis (Massey and Wygant 1954), but with little or no success with D. brevicomis (Miller and Keen 1960). , 8. Drowning: The storing of infested logs in mill ponds has control value if the logs are submerged six weeks or longer then turned so as to submerge the upper area for an addi- tional period of time. The exposed surface may also be treated with a chemical. This method has also been used to prevent in- festation of logs by ambrosia beetles. 9. Chemical control: Insecticides applied as sprays in a fuel oil carrier have been used extensively for bark beetle control. Chem- icals used include orthodichlorobenzene, ben- zene hexachloride, ethylene dibromide, and chlorodane. These have been used in various concentrations at the rate of about four fluid ounces per square foot of bark or until the spray begins to nm off. They are most effec- tive when air temperatures exceed 16 C (60 F). Althovigh chemical control is the most ef- fective and least expensive means of bark and ambrosia beetle control, the chlorinated hy- drocarbons used have had an adverse effect on birds and other wildlife, due to biological magnification in the ecosystem. Dvie to pub- lic pressure to conserve the wildlife, their use has declined dramatically. 10. Pheromone traps: Pheromone (sex at- tractant) traps have been remarkably success- ful in the control of many insects. Although numerous experiments have been conducted with bark beetle pheromones (with or with- out tree resins, alcohol, or combinations of these), successful control has not been achieved. In spite of the failures, it offers great promise of eventual success. CLASSIFICATION History Five scolytid species were listed by Lin- naeus (1758) in his tenth edition of Systema Naturae, in which the foundation of modern animal classification was established. All were treated in the composite genus Der- mestes of the order Coleoptera. Geoffroy (1762) established the first genus {Scolytus) within the group. At that time family-group categories did not exist. Later, when family- group names were introduced, early writers placed scolytid genera in various groups of Coleoptera, such as Bostrichi or Bostrichidae (Latreille 1804, Erichson 1836), Curculionites or Curculionidae (Latreille 1807), or the non- Linnean Xylophaga (Ratzeburg 1837, Eich- hoff 1864). The first valid family-group name involving these insects was Scolytarii (Lat- reille 1807:273), established as a subdivision of Curculionites and based on Scolytus Geoffroy, 1762. Subsequent authors have sub- divided the group into a complex system of subfamilies and tribes (Wood 1978). At the present time approximately 6,000 species of Scolytidae in the world fauna are known; these are distributed among about 181 gen- era. About one-fourth of the named species occur in North and Central America. Taxonomic Position of Scolytidae The Coleoptera are divided into four sub- orders, of which the largest and most special- ized is the Polyphaga (Crowson 1967). The Polvphaga are subdivided into 18 super- families, of which Curculionoidea (formerly designated as the suborder Rhynchophora) is the largest and most highly evolved (Crowson 1967). Within the Curculionoidea the fami- lies may be classified by characters summa- rized in the following key (modified from Crowson 1967). 34 Great Basin Naturalist Memoirs No. 6 Fig. 11. lload stnicture of Curculionoidca: \-C, Stcnorrlis hrciis (Ciirciilionidae, Cossoninae), lateral, dorsal, and caudal aspects, respectively; D-F, Uijhirgops r. ru^iprnnis (Scolytidae), lateral, caudal, and dorsal aspects, respec- tively; C-H, Ip.s mexicanus (Scolytidae), ventral and lateral aspects; I, Rhyncolu.s kmmltoni (Curculionidae), ventral a,spect; J, Cimbcris attehiboides (Nemonychidae), ventral aspect. Internal head structure is indicated bv broken lines, externally visible features by solid lines. The anterior tentorial arms are not developed in species illustrated here. \h- breviations: ai, antennal insertion or scrobe; aps, apodeinal inflection of pregular suture; cm, cervical membrane at- tachment; dat, dorsal arms of tentorium; dfm, dorsal margin of foramen magnum; gs, gular suture; hy, hypostomal arm; mgs, median apodeme formed by inflection of gular suture; mtp, median tentorial pillar; p, pregula; pap, paired apodemal plates of gular structure; pg, postgula; ps, pregular suture; ptb, posterior tentorial bridge; ptp, pos- terior tentorial pit; vfm, ventral margin of foramen magnum. 1982 Introduction 35 Key to the Families of Curculionoidea 1. Gular sutures (or their Ridiments on margin of foramen magnum) widely sepa- rated (Fig. llj); maxillary palpi 4-segmented; antennae never geniculate; lar- val thoracic spiracle mesothoracic or intersegmental, mandibular inola some- times present, 2-segmented thoracic legs sometimes present 2 — Gular sutures confluent between small postgula (on margin of foramen mag- num) and anterior limits of tentorium (at angle between ventral surface of head and rostrum) (Figs. 11-12); maxillary palpi 2- or 3-segmented (except Aust- roplatypus in Platypodidae and Attelabidae); antennae sometimes geniculate; larval thoracic spiracle on prothorax or intersegmental, mola never present, thoracic legs absent (except 1-segmented in some Brenthidae) 6 2(1). Adult labrum distinct and separate; maxillary lacinia distinct, palpi flexible; larval mandible usually with a mola, thoracic legs present 3 — Adult labnmi fused to head, not free; maxilla without a true lacinia, palpi rigid; larval mandible without a mola, thoracic legs absent 4 3(2). Tentorium and gular sutures largely to entirely obsolete; pronotum with lateral margins acutely raised; inner surface of elytra near costal margin with a flange; visible abdominal segments 1-4 connate; larval clypeus distinct from frons or head retracted Anthribidae — Tentorium present, gular sutures distinct from margin of foramen magnum to posterior tentorial pits (Fig. llj); lateral margins of pronotum rounded, not marked by an acutely elevated, longitudinal costa; inner surface of elytra near costal margin without a flange; visible abdominal segments freely movable; larval clypeus fused to frons, head never deeply retracted into prothorax Nemonychidae 4(2). Inner surface of elytra near costal margin with a flange; gular sutures moder- ately long to very long; antennae filiform, inserted some distance from base of rostrum; lateral margins of pronotum rounded; coxae subcontiguous; tarsi pseudotetramerous Belidae — Inner surface of elytra near costa without a flange; gular sutures very short, not visible with head in normal position; antennae clubbed or if not, then tarsi pseudotrimerous 5 5(4). Antennae clubbed; pronotum with lateral margins acute; tarsi pseudotetra- merous, segments 2 and 3 broadly bilobed; rostrum long, antennae inserted at its base on posteroventral surface Oxycorynidae — Antennae not clubbed; tarsi pseudotrimerous, only segment 2 bilobed; rostrum comparatively short, antennae inserted some distance from base on lateral surface Proterhinidae 6(1). Pregular sutures present, a distinct pregular sclerite between median gular suture and labial articulation (Fig. IIG, ps) rostrum primitively absent 7 — Pregular sutures absent, pregular sclerite not evident (Fig. Ill); rostrum very long to secondarily short 8 7(6). Tarsal segment 1 as long as 2-5 combined (except shorter in Protophtypus, Protohylastes, Coptonotus) (Fig. 13); head as wide as pronotum; pronotum usu- ally with a distinct lateral constriction near middle; antennal club without su- tures (except obscure in Coptonotus); apical mucro on protibia formed primi- tively from middle apical process; lateral denticles on protibia never socketed . Platypodidae 36 Great Basin Naturalist Memoirs No. 6 — Tarsal segment 1 not longer than segment 2 or 3 (Fig. 23, etc.); head con- spicuously narrower than pronotum, often concealed by pronotum when viewed from dorsal aspect; apical mucro on protibia formed primitively from mesal apical process; lateral denticles on protibia usually socketed Scolytidae 8(6). Antennae straight, club usually not developed; labial palpi minute, inserted in deep, ventral pits; rostrum often strongly sexually dimorphic; trochanters nor- mal; larval thoracic legs usually present, frontal sutures reaching articulating membrane of mandibles, abdominal segments with three or four tergal folds Brenthidae — Antennae clubbed, usually geniculate (if not then trochanters elongate); rostral sexual dimorphism less conspicuous; larval thoracic legs indistinct or absent, if frontal suture reaches articulating membrane of mandible then abdominal segments with only two folds 9 9(8) Antennae not geniculate, or trochanters long; larval frontal sutures reaching articulating membrane of mandible, abdominal terga with two dorsal folds Apionidae — Antennae usually geniculate, trochanters rarely long; larval frontal sutures not reaching articulating membrane of mandibles, abdominal terga with three to four transverse folds Curculionidae Fig. 11 contiiuu'd, parts (i-I (A-I redrawn from Wood 1973:79-80). Family Status of Scolytidae The Platypodidae and Scolytidae are unique among those curculionoids with one median gular suture in having a pair of dis- tinct pregular sutures that delimit a pregular sclerite immediately behind the oral area on the ventral surface of the head (Fig. IIG). These two families occupy a unique ecologi- cal niche as subcortical borers in unthrifty or dying woody plants in which paired (either monogamous or polygynous) parent adults excavate galleries within a host and together reproduce and defend their brood (at least temporarily) in those tunnels. Largely be- cause larval characters were not foimd to dis- tinguish these two families from Curcu- lionidae, Crowson (1967) reduced the time- honored families Platypodidae and Scolytidae to subfamilies of Curculionidae. In view of the unique adult gular character and the lim- ited and apparently superficial search for 1982 Introduction 37 Fig. 11 continued, part J (Redrawn from Crowson 1967:157). larval characters, his action is considered un- tenable. Both groups have been restored to family status (Wood 1973). The Platypodidae and Scolytidae occupy the same basic ecological niche; the ambro- sial habit that is almost universal in Platypo- didae has arisen, apparently independently, in 3 of 11 tribes of Hylesininae and in 5 of 14 tribes of Scolytinae. The two groups inter- grade anatomically, behaviorally, and ecolog- ically. They are obviously very closely re- lated to one another, but are retained as separate families until their status is more fully investigated. Various classifications of subfamilies and tribes have been presented for Scolytidae (Wood 1978). Following a review of about 90 percent (412 of 472 nominate genera and subgenera) of the valid genera in the world fauna, 2 subfamilies containing 25 tribes were recognized (Wood 1978). The following key to subfamilies and tribes of Scolytidae sum- marizes the characters on which that classifi- cation is based. Fossil History Comparatively few fossil Scolvtidae are known. Walker (1938) attributed engravings in petrified Triassic wood from Arizona to scolytid beetles designated as Paleoscohjtus divergus Walker, Paleoipidus perforatus Walker, and Paleoipidus marginatus Walker. The engravings of Paleoscohjtus are too large (5 mm wide) and branch in a pattern un- known in modern Scolytidae. The Paleoip- idus holes in the wood are not cylindrical; there is no evidence that they were formed by scolytids, but this possibility should not be discarded. However, engravings on Cre- taceous coniferous bark from Europe, report- ed by Brongniart (1877), almost certainly were made by phloeophagous Scolytidae. Scudder (1876, 1878, 1893) named three scolytids from American Eocene deposits as follows: Polygraphus wortheni Scudder, Roan Mts., Colorado Dryocoetes carbonarius Scudder, Green River, Wyoming Dryocoetes impressus (Scudder), Green River, Wyoming Schedl (1947) reviews the fossil Scolytidae found in Baltic amber from the Oligocene. The 22 species cited represent the genera Hylastes (1), Hylurgops (5), Hylescierites (2), Xylechinites (1), Carphoborites (2), Phloeosi- nites (8), Taphramites (2), and Tophrorychus (1). Specimens have been taken in American amber, but have not been reported. Hopkins (1902a) indicates that Dryocoetes impressus probably is not a scolytid. In addi- tion to the Eocene forms cited above, the fol- lowing were named (Scudder 1893, Wickham 1913, 1916) from the Florissant Miocene de- posits in Colorado: Phloeotribus zimmennanni Wickham Leperisinus extractus (Scudder) Hylurgops piger Wickham Hylastes americanus Wickham Pityophthoridea diluvialis Wickham Adipocephalus hydropicus Wickham Xyleborites longipennis Wickham 38 Great Basin Naturalist Memoirs No. 6 ^Epicranial tulbin. Lateral margin Mrtaierqum — - khlra ,c /,?f -x<- ^ / ••v^ ^' 1 / . s V I'riilliiira.r — 'Misotlwrax Fig. 12 A,B. Dcndrortontis valcns, (A) dorsal and (B) lateral aspects. Present usage of interstriae (= interspace in this figure), terguni and sternum (= tergite, sternite). (After Hopkins 1909:6, 9.) Quaternary fossils of living North Ameri- Phloeotribus piceae Swaine can species (age 10,000 years) are reported Polygraphus rufipennis (Kirby) by Ashworth, Clayton, and Bickley (1972) Sco/t/fus piceae (Swaine) and Ashworth and Brophv (1972) as follows: Orthotomicus caelatus (Eichhoff) 1982 Introduction 39 THORAX- '^Epistomal process £1 > ^c:> ^ k ^ S ^ i .^ ^ '^ ^ = i s=r.i ■^. ^ t: 2 -< t =; 3 =. 2 -c Fig. 12 C. Dendroctonus valens, ventral aspect. (After Hopkins 1909:8. Ips probably perturbatus (Eichhoff) Older Quaternary fossils (age 70,000 years) were taken in Ontario by Drs. Alan and Anne Morgan (in prep.) as follows: Phloeosinns pint Swaine Phloeotribus piceae Swaine Carpfioborus carri Swaine Carphoboriis andersoni Swaine Polygraphus rufipennis (Kirby) Scolyttis piceae (Swaine) Pityogenes or Pityokteines sp. Pityophthorus probably puberulus (LeConte) The occurrence of representatives of mod- em genera of both subfamilies of Scolytidae in the Eocene suggests an earlier origin of the family than has been indicated previously. Fossil evidence coupled with that from biogeography indicates an origin at least as early as the early Cretaceous and perhaps as early as late Triassic. Discussion of Characters Previous classifications of higher categories in the Scolytidae and a more complete dis- cussion of potential characters and their sig- nificance appears in Wood (1978). A brief summary of that discussion is presented here. Characters of greatest use in determining phylogenetic relationships and the limits of the higher categories within the family in- clude the following. Head.— In curculionids, Hylesininae, and primitive Scolytinae (Scolytini, Ctenophorini, Scolytoplatypini, Carphodicticini) the poste- rior region of the head is essentially truncate (Fig. 14A). In the remaining Scolytinae, com- mencing with Micracini and progressing to the Xyleborini and Corthylini, the dorsal oc- cipital area is produced caudad (Fig. 14B). This is an obvious specialization. The subrostrate condition of Hylastini, Hy- lesinini (part), Hyorrhynchini (part), and Scolytini (part) is probably more closely cor- related with habit than with phylogeny. The- pregular sutures evidently prevented the de- velopment of a rostrum in Platypodidae and Scolytidae, since the anterior arms of the ten- torium are intact (they are absent, or at least broken, in curculionids). The eye varies from oval and entire to elongate and entire or emarginate to 40 Great Basin Naturalist Memoirs No. 6 Fig. 1.3. Tibia and tarsus of Phittjpus paraUclus, poste- rior face. completely divided. While eye shape and po- sition are very useful in the recognition of genera, it should be pointed out that some of the most aberrant eye shapes occur in some of the most primitive tribes. In general, how- ever, the oval, entire eye is primitive; depar- tures involving elongation or emargination are specializations. The antennal funicle may have a maximum of seven segments as in other curculionoids. Within Scolytidae the segmentation may be reduced to as few as three segments in Hy- lesininae or one in Scolytinae. Reduction in the number of segments from seven is consid- ered as specialization. The antennal club is formed from three segments. In primitive .scolytids, as in many other curculionoids, it is conical (Hylastini, some Hylesinini). Specializations may include compression (flat) or oblique truncation, ei- ther with or without the loss of sutures. The club may be symmetrical or asymmetrical, with the sutures equal on both sides or with the sutures on the posterior face stronglv dis- placed toward the apex. In Phloeotribini the intersegmental lines are constricted, thereby forming a sublamellate club with indepen- dently movable segments. Proth()R.\x.— The primitive prothorax ap- parently was short and more or less cvlindri- cal. Specializations include a substantial re- duction in the sternal areas accompanied by a change from widely separated to con- tiguous coxae. A precoxal costa was associ- ated with that change in some primitive groups. Tlie dorsal area in specialized groups is declivitous on the anterior area, armed by asperities, and much narrower anteriorly. In Diamerini, Bothrosternini (part), Scolytini, and Ctenophorini the lateral margin of the pronotum is costate. This costa appears to be a strengthening device associated with a sub- concave pleuron in these comparatively primitive tribes. An analogous raised line in Cryphalini and Corthylini apparently has a different origin and function. Mesothorax, elytra.— While numerous characters of specific and generic interest oc- cur on the mesothorax, items of phylogenetic interest involve the basal margins, interstriae 10, and the mechanism for locking the elytra in position when at rest. In all Hylesininae the basal margin of each elytron is procurved and armed by a series of crenulations. The curvature results from a su- tural emargination formed to accommodate the depressed, rounded scutellum. The crenu- lations are shared by a few species of Cnemo- nijx (Scolytini), but otherwise are restricted to the Hylesininae. A few Diamerini and Bothrosternini have an elevated marginal costa in place of the crenulations. In Scoly- tinae the elytral bases form a straight trans- verse line across the body and the scutellum is large, flat, and flush with the surface. Most primitive tribes contain at least some members having interstriae 10 continued to the apex. In more specialized groups striae 9 and 10 converge near the middle of the elytra, thus eliminating the posterior half of interstriae 10. On the sutural and costal margins of the elytra near the base are grooves that inter- lock at the suture with the opposite elytron and on the costal margin with the mete- pisternum. The details of these structures are useful in determining phyletic relationships of major groups. Metathor.\x, tergum.— In some Hylesi- ninae (Diamerini, Bothrosternini, Phloeotri- bini, Phloeosininae, Hypoborini, Polyg- raphini) the .scutellar area of the metanotum fuses with the postnotum, thus eliminating the intersegmental suture. The inter- segmental suture is present in the remaining Hylesininae and in all Scolytinae. In addition, the scutoscutellar suture follows a much shorter, more lateral route in those groups with a fu.sed postnotum. These two charac- ters make possible a major division of the Hylesininae. Metathorax, pleuron.— In Curculio- nidae, primitive Hylesininae, and primitive 1982 Introduction 41 Fig. 14. A, Hylastes nigriniis, lateral aspect of head; note, eye, antenna, and undeveloped dorsal occupital area (Left side near middle of foramen magnum damaged in preparation). B, Ips woodi. ventrolateral aspect of head; note postgula, gular suture, pregula, and extended dorsal occipital area. Scolytinae the pleural suture descends verti- cally from the pleural wing process to the groove on the episternum that receives the costal groove of the elytra. At that point the pleural suture turns abruptly and follows the groove caudad to near the pleural coxal pro- cess. The anterior end of the lower costa that forms the metepisternal groove is higher, of- ten spinelike, and may persist when the re- mainder of the groove is lost. In the higher Hylesininae and higher Scolytinae the groove is lost, the episternal spine is displaced ven- trad, and the pleural suture runs a much more direct route from wing process to coxal process, often quite remote from the position of the costal margin of the elytra. In Crypha- lini the episternal spine is modified and in Corthylini it is lost and replaced by a small, transverse groove. Legs.— Tibial characters have been used extensively in scolytid classification. The primitive protibial form is thought to be sim- ilar to that of Protohylastes (Fig. 35), which has three apical spines (Wood 1973a). The small mesal spine apparently becomes the apical spine of Scolytidae; the larger, middle spine becomes the apical spine of Platypo- didae and the major lateral spine of Scolytini, etc.; and the smaller, lateral spine becomes a minor lateral spine in all groups. These spin- es, and some supernumerary denticles, are not socketed (Fig. 29). All these lateral spines are replaced by socketed teeth (Fig. 34), pre- sumed to be of setal origin, in all higher groups (Wood 1978). In several of the more primitive groups tarsal segment 3 is broad or bilobed. In Dia- merini (part), Xyleborini (part), and Xylocto- nini the tarsi tend to be laterally compressed and retracile into tibial grooves. The tarsal characters are of some value in classifying genera of certain tribes. Abdomen.— In Carphodicticini, Ipini, Dryocoetini, Xyleborini, and all Platypodidae female abdominal tergum 8 is visible, pub- escent, and almost as large as in the male. In all other scolytids and most curculionids it is of reduced size, lacks pubescence, and is tele- scoped beneath and hidden by tergum 7 (Fig. 14C). In Hylastini, many Hylesinini, and Phloeotribini the posterior margin of male tergum 7 bears a median, bituberculate, stri- dulatory device that scrapes against the adja- cent inner surface of the elytra. The value of this character is uncertain, it is not always present in groups that normally possess it. It may be significant that a comparable charac- ter occurs in most Platypodidae. Phylogeny The Scolytidae and Platypodidae appar- ently arose as a monophyletic unit from the 42 Great Basin Naturalist Memoirs No. 6 male female Fig. 14C. Abdominal terga of Cryphalus pubescens: Male, segments 7 and 8 (above); female, .segment 7 (be- low). (After Wood 1954:1087.) segment of the Curculionoidea having one gular suture before pregular sutures were lost in the remainder of the phyletic hne that gave rise to the Brenthidae, Attelabidae, Apionidae, and Curcuhonidae, but well after the groups having two gular sutures, or rem- nants of them (Belidade, Nemonychidae, An- thribidae), had branched from the main stem of evolutionary development. Long after the basic scolytid-platypodid characters and habits had been fixed, this evolutionary line radiated into three groups at approximately the same geologic time (possibly late Trias.sic to early Cretaceous). These three groups presently include representatives among their primitive tribes having (1) a 7-segmented antennal funicle, (2) a fully formed, pub- escent female tergum 8 basically similar to that of the male, (3) basically similar tibiae that lack socketed supernumerary spines on the lateral margins, (4) a fully developed in- terstriae 10, (5) the same general body habit- us, and (6) the phloeophagous habit. The evi- dence is inconclusive as to which of these three groups branched from the main .scoly- toid evolutionary stem first; however, be- cause of the somewhat larger number of primitive characters and the different ap- pearance (probably related as much to dis- tinctive habits as to genetics), coupled with imique specializations, the Platypodidae are regarded as the most primitive. For similar reasons the Hylesininae are considered to be more primitive than the Scolytinae, but the genetic relationship between primitive Platypodidae and primi- tive Scolytinae may be closer than either of these is to the Hylesininae. The Scolytinae are considered to represent the main line of scolytid evolution. The accompanying den- drogram (Fig. 15) illustrates possible phyloge- netic relationships of major groups within these families. The most primitive known representative having hylesinine characters is Protohylastes. It could equally well be placed as the most primitive representative of Platypodidae (Coptonotinae). It shares many characters with Coptonotus. Except for the antennal club and tibiae, it could be placed in the Hy- lastini with complete confidence. It is placed as an aberrant genus of Coptonotini until more can be learned about its structure and habits. Platypodidae.— The pregular sutures, nu- merous other structural details, and the shared ecological niche suggest a close rela- tionship to the Scolytidae. The 7-segmented funicle {Protohylastes and Coptonotus), strongly procurved antennal sutures (Cop- tonotus), fully developed female abdominal tergum 8, complete interstriae 10, route fol- lowed by the scutoscutellar suture, route fol- lowed by the metapleural suture, tibial char- acters, elytral locking mechanism, the polygynous habit in Protoplatypus, and other characters indicate a closer, but very primi- tive, connection to Scolytinae rather than to Hylesininae. The closest affinity of Platypo- 1982 Introduction 43 Corthylini Xyleborini Polygraphini Hypoborin Phoeosinini Xylotenni Dryocoetini Crypturgini Hylastini Platypodinae Schedlanus Coptonotus Protohylastes Platypodidae Fig. 15. Dendrogram illustrating possible phylogenetic relationships of major groups within the Scolytidae and Platypodidae. didae (through Protohylastes) to Hylesininae appears to be through Diamerus (Diamerini), which possesses several very specialized fea- tures. The closest affinity (through Pro- toplatypus) to Scolytinae appears to be through Cnemonyx (Scolytini), Scolytodes (Ctenophorini), Carphodicticini, and Scolytoplatypodini. Hylesininae.— The fusion of the metano- tum to its postnotum apparently took place very early in hylesinine evolution as evi- denced by the occurrence of tibiae without socketed teeth in both divisions (Hyorrhy- chini, Diamerini, and Phloeotribini). More primitive characters, with fewer specialized ones, appear to be associated with Hylastini, Hylesinini, and Tomicini (listed in increasing order of specialization), with the Phrixoso- mini and Hyorrhychini representing special- ized relicts of otherwise primitive groups. In the more specialized hylesinine line are found the more primitive tibiae {Diamerus, Aricerus), pronotums (Diamerus), elytral bases (Bothrosternini, Diamerus), and other characters, but they also exhibit the greatest specializations (reduced funicular segmenta- tion, aberrant antennal club with loss of su- tures, etc.). The fusion of the postnotum ob- viously took place very early in hylesinine evolution, as evidenced in that group by the much greater structural and biological diver- sity. The Diamerini and Bothrosternini, which appear to be geographical replace- ments of one another, share the greatest num- ber of primitive features; they also appear to 44 Great Basin Naturalist Memoirs No. 6 have diverged further than the other groups from the original ancestral line. The Phloeotribini also diverged rather early as evidenced bv the protibia of Aricerus and by the very different, sublaniellate, antennal club. The Hypoborini and Polygraphini ap- pear to be specializations that diverged rather recently from the Phloeosinini. ScoLYTiNAE.— The basic stnictural rela- tionship of most Scolytinae to Platypodidae is closer than to Hvlesininae, although the bio- logical affinity is closer to most Hylesininae. The strongly procurved antennal sutures of Coptonotus (and the obscure lines that sug- gest obsolete sutures in other Coptonotinae and a few Platypodinae) is a common charac- ter in Scolytinae (Scolytini, Ctenophorini, Micracini, Xyloctonini), but occurs only in Diamerini {Diamerus) and Bothrosternini {Pa- giocerus, Eupagiocerus) in the Hylesininae. The Scolytini apparently diverged very early from the main evolutionary line in Scoly- tinae, as evidenced by antennal, tibial, meta- pleural, and other characters. The divergence of Scolytoplatypodini and Ctenophorini soon followed, as evidenced by a significant change in tibial characters, and these geo- graphical replacements then diverged from one another. The remaining Scolytinae re- place unsocketed lateral tibial spines with socketed teeth that apparently were derived from setae. Except for the socketed tibial teeth, Carphodicticini most nearly resembles my concept of a primitive platypodid in an- tennal, frontal, pronotal, coxal, metapleural, metatergal, and abdominal characters. How- ever, the tibiae, and other characters, place it more nearly intermediate between Pro- toplatypus and Dryocoetini. The Cryptur- gini, Dryocoetini, Ipini, Xyloterini, and Xy- leborini represent a unit of closely related tribes. Micracini and Cactopinini appear somewhat related, as do Xyloctonini and Cryphalini. The relationship of Corthylini to other tribes is not clear; they exhibit some very primitive features as well as many of the most specialized ones in the family. BIOGEOGRAPHY Extraterritorial Affinities To establish a basis for this discussion, it is assumed that the following hypotheses and theories are essentially correct: (1) the biolog- ical species concept (Mayr 1963) is valid, (2) biological speciation occurs through a pro- cess of geographical isolation, during which time isolated populations of a parent species differentiate and become reproductively iso- lated from one another (Mayr 1963), and (3) a process of continental drift has occurred that has had an effect on the geographical distri- bution of animal groups (Wegener 1924). It is also necessary to eliminate from this dis- cussion those species and genera that are known to have been introduced to or export- ed from North and Central America through modern human commerce (Wood 1977). Most notable in this regard are the imported genera Hylastinus, Hijpocnjphalus, and Premnobius, and the exportation of Gnatho- trichits materiariiis (Fitch) to France and Mi- croborus boops Blandford to Africa. An analysis of the tribal groups of Scoly- tidae reveals the following relationships (Ta- bles 1, 2). The Cactopinini are found only in southwestern North America. The Both- rosternini and Ctenophorini are restricted to the tropics of North and South America; Scolytini (except Scolytus extends to Eurasia) and Corthylini (except Pityophthorus extends to Eurasia; there are also a few aberrant Afri- can forms) are almost exclusively American. Phloeotribini are largely American, with a few species of Phloeotribus in Eurasia, except that the monotypic Aricerus appears to have reached Australia very early in the formation of the group. The Polygraphini, Crypturgini, and Xyloterini are of obvious Eurasian origin and reached northern North America rather recently. The Hylastini, Hylesinini (except Phloeoborus that was derived biogeographi- cally from South America), and Ipini (except Acanthotomicus, which probably reached South America from Africa in pre-Tertiary time) are also of Eurasian origin, but the in- volvement appears much older and more complex. The Phrixosomini, Hypoborini, and Micracini apparently reached North and Central America rather recently from South America, but exhibit a strong, much earlier relationship to the African fauna. The Tomi- cini, Phloeosinini, Dryocoetini, Xyleborini, and Cryphalini are diverse and indicate more complex endemic origins and inter- relationships with other areas. The Hyorr- hynchini, Diamerini, Scolytoplatypodini, 1982 Introduction 45 Carphodicticini, and Xyloctonini do not oc- cur in North America, although two of three genera of Carphodicticini occur in South America and Diamerini (Old World) appears to replace geographically Bothrosternini, and Scolytoplatypodini (Old World) replaces Ctenophorini. The principle original centers of adaptive radiation in the family appear to be North America for Hylastini, Tomicini, and Cac- topinini; South America for Phrixosomini (and Africa), Bothrosternini, Phloeotribini, Scolytini, Ctenophorini, Micracini (and Af- rica), and Corthylini; Eurasia for Hylesinini (and Africa, except South America for Phloeoborus), Phloeosinini (and Africa), Ipini (and Africa), Xyloterini, and Cryphalini (and Africa); Africa for Hypoborini, Polygraphini, Crypturgini, and Dryocoetini. The radiation of Xyleborini has progressed explosively from the Tropics, but the pattern is not yet clear. Secondary radiations of each tribal group may also occur in newly occupied areas. For example, the Ipini apparently originated in tropical Africa as the precursors of Acan- thotomicus then spread northward into Eu- rasia, giving rise to a new stock. The portion of the new stock that remained in Eurasia ap- parently gave rise to Orthotomicus and Pi- tyogenes, and the portion that reached North America gave rise to Ips and Pityokteines. Later, elements of Orthotomicus and Pitijo- genes reached North America and elements of Ips and Pityokteines reached (or returned to) Eurasia to give rise to the present faunas. This is based on the fact that, of nine species groups of Ips in North America, six are shared with Eurasia; no unique group occurs in Eurasia. Similarly, in Pityokteines only one of three groups reached Eurasia, in Orthoto- micus only one of several groups reached North America, and in Pityogenes only three of several groups reached North America. Comparable multiple migrations appear to have affected several other groups with equal magnitude when faunal transfers were suffi- ciently early to permit secondary radiations. In some instances the migrations were so re- cent that speciation of the populations on dif- ferent continental land masses may not yet be complete. Table 3. A comparison of the number of genera of Scolytidae in North and Central America, listed by tribes, to the world fauna. North World America Fauna Hylesininae Hylastini 3 3 Hylesinini 4 11 Tomicini 4 14 Phrixosomini 1 1 Hyorrhynchini 3 Diamerini 4 Bothrosternini 5 5 Phloeotribini 1 2 Phloeosinini 4 11 Hypoborini 2 4 Polygraphini 3 6 Scolytinae Scolytini 4 4 Ctenophorini 4 4 Scolytoplatypodini 1 Micracini 7 11 Cactopinini 1 1 Carphodicticini 2 Crypturgini 2 6 Dryocoetini 4 15 Ipini 5 5 Xyloterini 2 3 Xyleborini 6 10 Xyloctonini 5 Cryphalini 9 23 Corthylini 23 27 Totals 94 181 Table 4. A comparison of the species of Scolytidae occurring in North and Central America bv geographical area. Species occurring in more than one area may be listed more than once, but the total is of the actual numbers of spe- cies in the fauna. Hyleslninae Hylastini Sciertis Hyhirgops Hylastes Alaska and Canada USA Mexico Central America Total species in fauna 2 2 2 4 6 5 3 7 6 13 6 1 15 46 Great Basin Naturalist Memoirs No. 6 Table 4 continued. Alaska and Canada USA Mexico Central America Total species in fauna Hylesinini Hijlastin us Hylesinus Alniphagus Phloeoborus Tomicini Xylechinus Pseudohylesinus Hyhirgopinus Demlroctonus 1 1 1 3 7 3 1 9 2 2 2 3 5 5 2 2 2 6 9 7 9 3 11 1 1 1 8 13 9 7 16 Phrixosomini Phrixosoma Bothrostcrnini Cnesinus Pagiocerus Bothrosternus Eupagiocenis Stemohothrus 2 19 26 41 1 1 1 1 1 2 2 1 3 3 2 2 Phloeotrihini Phloeotribiis 14 16 27 Phlocosinini Dcndrosinus Pliloeosinits (Mrphotoreus Chramesus Hypoborini Chdctophlociis lApdrtlniim Polyjfraphini C(irph()l)ius C(ir})h<)l>()rus Polijgr(ip}\us 1 1 1 2 10 24 7 1 27 1 1 1 8 24 13 37 1 9 9 1 15 2 3 1 5 1 1 1 2 7 18 2 20 2 3 3 ScOLYTIiNAE .Scolytini Cnemonyx Camptocerus Srolytopsis Scolytu.s Ctenopliorini Microhorus Pyciuirthrum Ciymnochilu.s Scolytodes 2 11 10 21 5 5 2 1 2 12 20 12 7 34 2 2 4 1 2 6 6 3 3 4 1 17 56 67 1982 Table 4 continued. Introduction Micracini Fsi'tiilothysanoes Stcnorleptus Thijsanoes rhlot'odeptus Micracis Micracisella Hiflociiriis Alaska and Canada USA Mexico Central America 47 Total species in fauna 1 15 48 7 67 1 1 2 7 12 1 15 10 1 11 1 4 12 6 18 5 14 4 20 13 15 9 35 Cactopinini Cactopinus 11 14 Crvptiirij;ini Dohirgus Cnjpturgus Dryocoetini Dendrocmnulus Lymantor Dryocoetes Coccotrypes 3 5 19 23 2 1 2 7 7 7 5 2 5 7 Ipini Pitogenes Pityokteines Acanthotoniicus Orthotomicus Ips 5 6 2 7 5 6 6 1 3 3 1 1 1 .5 24 8 5 24 Xyloterini Xyloterinits Trypodendron Xyleborini Preinnobius Sampsonius Xylosundrus Dryocoetoides Xyleborus Xylehorinus - 1 1 1 1 2 3 4 4 3 3 6 1 2 2 3 19 20 66 87 1 2 4 7 10 Cryphalini Trypophloeus Stegcvnein.s Ernoporicu.s Procryphalus Scolytogenes Cryplialus Hypocryphalus Triscliiduis Hypothenemus Cryptocarenus 3 4 4 1 5 5 1 1 2 2 2 1 5 3 7 2 3 3 1 1 1 1 3 3 21 25 21 39 2 4 5 5 48 Great Basin Naturalist Memoirs No. 6 Table 4 continued. Corthylini Styplilosoina DendroteruH Arapttis Connphthocramilus Spen)HypIitliorus rseudopityophthorus Pityuborus Pityotrkhus Gnathuleptiis Conoplithoriis Pityophthorus Dacnophthorus Gnathotrichus Gnatliotrupes Tricolus Amphicranus Glochinocerus Mefacortbyhts Monorthrum Microcorthylus Cortliycyclon Corthylocurus Corthyhis Total Alaska and Canada 4 41 3 2 1 179 USA 2 I 12 2 2 10 99 7 5 4 477 Mexico 7 25 14 5 4 102 1 11 6 9 1 22 4 1 4 17 605 Central Total species America in fauna 1 1 6 13 38 54 1 1 1 1 3 23 1 7 2 4 4 14 41 218 2 2 4 15 5 5 21 24 24 31 2 2 4 4 43 60 12 14 6 6 5 6 46 58 632 1430 The faunal connection (over the Bering land bridge) between North America (Alaska) and Asia (Chukchi Peninsula) appears to be recent. This is indicated by the occurrence in both areas of identical or very similar species of Scolytidae, particularly those that breed in Picea. For example, Dryocoetes autographus and Trypodendron lineatum occupy both areas and apparently have not speciated. In the following series of names speciation is evidently complete, although the members of each pair are so similar to one another that identification is difficult. American sf)ecies llylurgops rugipcnnis Polygraphus rufipennis Dcndroctoniis ptinctatus Hylastes nigrinus XyU'chin us ameriranus Polygmphus convexifron.s Phlocotribtis piceae Ips pcrtiirhatus Crypturgus horcaUs Dryocoetes affaher Cryphalus nificollis Eurdsian species U. oluhratus P. poligrciphus D. miccms H. ctinicularius X. pilosus P. grandiclava P. spinulosus I. typographus C. tuberosus D. pint C. asperatus Of the 24 American species occurring in Picea north of the 60th parallel, I have estab- lished a definite phenotypic relationship to Asian species for 13 of them. Adequate mate- rial for comparison was not available for 7 of the remaining 11; the other 4 have no Asian counterpart {Scierus annectens LeConte, Dendroctonus rufipennis Kirby, Ips tridens Mannerheim, and /. borealis Swaine). A com- parison of species from other hosts and from more southern areas is somewhat less dramat- ic, but indicates a clear faunal relationship. Sixteen American genera contain species groups, all of which are represented in a more diverse Eurasian fauna; therefore, it is concluded that all species in these genera were derived directly or indirectly (through subsequent speciation) from Eurasia. These genera include: Phloeosinus (extensive secondary speciation) Hylesinus Polygmphus Carplioborus Trypophloeus Ernoporus Pityogenes Orthotomicus Procryphalus Cryph(dus Dohirgus (not now in Eurasia) Crypturgus Lymantor Dryocoetes Trypodendron Xyloterinus (not now in Eurasia) 1982 Introduction 49 Both Dohirgus and Xyloterinus are mon- otypic and endemic to North America, but they were undoubtedly derived from a Eura- sian source in that no potential ancestor or near relative exists in the Western Hemi- sphere. Nine genera are much more diverse in North America, and all Eurasian species groups in these genera are represented in America; consequently, it is concluded that all Eurasian species in these genera were de- rived directly or indirectly from North Amer- ica. These genera include: Hijlurgops Scolytus Hijlastes Pityokteines Xijlcchinits Ips Dendroctonus Pityophtliorus Phlocotrihus A southern faunal association is more diffi- cult to demonstrate, presumably because po- tential land connections occurred much ear- lier in geologic time and many more species are involved. However, several groups, repre- sented only in tropical America and tropical Africa, suggest shared genetic traits. Phrixo- soma and Cladoctonus appear to be very old, compact genera with no closely allied living relatives. Both are represented in both areas by several species that are so similar it is sometimes difficult to distinguish an Ameri- can from an African species; yet potential hosts for these genera abound in other tropi- cal areas where these beetles do not occur. Basically the same is true of Acanthotomiciis and Hypothenemus, although they are also represented in the Indomalayan-Australian region. Paired, but different, genera also oc- cur in tropical America and Africa in the Micracini and Hypoborini, and between Den- drocranuhis and Xylocleptes. In addition, the Ctenophorini (American) and Scolytopla- typodini (African) replace one another, as do the Bothrosternini (American) and Diamerini (African, etc.) and a few species groups with- in the Xyleboriis. The above discussion calls attention to a faunal exchange between North America and Eurasia sufficiently recent that speciation ap- parently is either not complete or that per- mits easv recognition of species or species groups on both sides of the Bering Strait. This route of faunal interchange was open to arctic and subarctic species at several times during the Pleistocene until quite recently in geologic time. However, forests were climati- cally stratified much as at present and it is probable that the only species exposed to the Bering land bridges during Pleistocene inter- glacial periods were those associated with the northern coniferous forest, namely Hylur- gops, Hylastes, Xylechinus, a few Phloeo- tribtis, Polygraphtis, a few Scolytus, Try- pophloeus, Procryphahis, Cryphalus, Cryp- turgus, Dryocoetes, Pityokteines, Pityogenes, Orthotomicus, Ips, Trypodendron, and Pityophthorus. For the most part, the speci- ation that followed migration of these species has been comparatively minor and species groups on both sides of the Bering Strait are easily recognized. Because the temperate for- ests have not reached arctic regions since late in the Tertiary, it must be assumed that spe- cies dependent on such hosts must have crossed the Bering land bridge during the Tertiary. It is probable that most Phloeosinus, Hylesinus, most Scolytus, Ernoporus, Do- hirgus (or its ancestor), Lymantor, Xylote- rinus (or its ancestor), and others, are in this category. Known fossils not only confirm part of the above speculation, but place several genera in invaded territory much earlier than had been supposed. These records include the fol- lowing (asterisks are used to identify genera invading new territory distinct from the con- tinent of probable ancestral origin; extinct genera were omitted): Baltic Amber (Oligocene) ° Hylurgops 'Hylastes Hylurgus (endemic) Tomicus (endemic) "Xylechinus Hylesinus Phloeosinus Polygraphus Carphoborus Cryphalus Taphrorychus (endemic) North America Hylurgops (Miocene) Hylastes (Miocene) "Hylesinus (Eocene) "Phloeosinus (Pleistocene) Phloeotribus (Miocene) "Polygraphus (Eocene) "Dryocoetes (Miocene) Xyleborus (Miocene) Pityophthorus (Miocene) It is curious to note from the above that Tomicus was present in Europe in the Oligo- cene, but it has never become established in North America even though a route for mi- gration has been open and breeding speci- mens have been intercepted here on several occasions during the past century (Chamber- lin 1939:215-216). It is also curious that Den- droctonus is not represented in the fossil 50 Great Basin Naturalist Memoirs No. 6 record nor has it invaded Eurasia until very recently (D. annandi may be an exception). In addition, 11 of the existing 20 tribes of North American Scolytidae are represented in the fossil record by modern genera. Seven of the nine tribes not represented are of trop- ical distribution or were probably too rare in temperate North America for one to expect fossilization. Because the apparent connection between southern South America and southern Africa was broken by continental drift no later than early Tertiary (most geologists place it 15-30 million years earlier), I had presumed that the availability of such a route for migration would not be reflected in the living scolytid fauna. Tliis is not the case. The above fossil record lists 12 modern genera that are 30 million or more years old in five different tribes. Furthermore, it is noted that, among groups now restricted basically to the Ameri- can tropics and Africa, the genera Phrixo- soma, Cladoctonus, Micracis, Acanthoto- micus, certain Hypothenemus, and certain Xyleborus groups, the paired but different genera in the Phloeosinini, Hypoborini, Micracini, and in the Dendrocranulus group of genera of Dryocoetini, the paired but dif- ferent tribal groups Bothrosternini and Dia- merini, and the Ctenophorini and Scolytopla- typodini suggest that such a connection did exist and that the basic patterns of scolytid phylogeny were established long before that land connection was severed. Based partly on the above dates and diver- sity, one might speculate that the Scolytidae originated in conjunction with the origin of coniferous gymnosperms perhaps as early as the Triassic, when conifers were a dominant plant group. In fact. Walker (1938) named Paleoscohjtus and Paleoipidiis from holes and engravings in petrified Arancariuxylon wood from the Triassic (Chinle formation) of Ari- zona. Whether or not these were made bv scolytids or their ancestors is open to question. American Biogeography Pleistocene glaciation affected the distribu- tion of Scolytidae in northern North America by causing extinction in some areas and pro- viding refugia in others. For example. Carphoborus andersoni Swaine is common in interglacial lake deposits in Ontario (Mor- gan, pers. comm.), but presently does not oc- cur south or east of the Northwest Terri- tories. Similarly, C. carri Swaine was common in postglacial deposits in western New York; this species presently is known from Manitoba and New Brunswick, but not from the intervening area. The present land bridge connecting North and South America has facilitated a faunal exchange between these areas. South Ameri- ca was an island during much of the Tertiary, but was connected to North America at the beginning and again at the end of that period (Darlington 1965). During the Pleistocene this land bridge formed and broke several times. In those periods when the land bridge was broken, a series of islands persisted and preserved much of the fauna that had mi- grated to them while the connection was complete. Many of these species had either migrated along mountain chains or adapted to the higher elevations on the islands, where they either preserved migrating populations or were modified through selection into new geographical races or distinct species. The groups most conspicuously restricted to high altitudes and affected by the "island" effect are the tropical Xylechinus, Gyinnochilus, Chrarnesus, Stegomertis, Dendroterus, Pseu- dopityophthorus, the xylomycetophagous Corthylini, and some Cnesinus. The island ef- fect also may have halted the southward mi- gration of the conifers, and all scolytids uti- lizing them as hosts, in northwestern Nicaragua. The speciation that resulted from the island effect combined with the later mi- gration of the Bothrosternini (except some Cnesinus), Dendrosinus, Phrixosoma, Phloeo- borus, Phloeotribus, most Scolytini (except some Scolytus), most Ctenopherini, many Hypothenemus, and Xyleborus in the lowland areas produced a rich faima that appears un- equaled elsewhere in the world in an area of similar size. Considerably more collecting and studv must precede a detailed analysis of the scolytid biogeography of this area. The most distinctive faunal area in North America appears to be the desert plateau re- gion from southern California, southern Ari- zona, and southwestern New Mexico to the Isthmus of Tehuantepec. A considerable 1982 Introduction 51 amount of endemism is evident here in the Micracini, Cactopinini, Dendroteriis, Pityoph- thonis, and, perhaps, in several other phloeo- phagous Corthyhni. Superimposed upon this desert plateau are those species that breed in conifers in the mountains that traverse the area and those that penetrate the moist low- land pockets of tropical forest on the margins of the desert region. Because 39 percent of all North and Cen- tral American Scolytidae are known only from their type series, and because most of these species are from Mexico to Nicaragua, a useful analysis of the biogeography of this area is not possible at the present time. In view of the faunal exchange that has taken place between North America and Asia, both geologically recent and ancient, it appears significant that only two species of Dendroctonus have reached Eurasia, and one of those in comparatively recent times. The high concentration of species and diversity in Mexico suggests a Mexican origin of Den- droctonus, with a comparatively recent in- vasion of north temperate areas. This possi- bility is supported by the fact that no endemic Ips species, which share the same hosts with Dendroctonus, have developed in Mexico. All Mexican Ips have distributions extending into the United States. Only four of 16 American species of Dendroctonus pres- ently do not occur in the Mexican plateau area, and all four are of recent origin (one of these is in Guatemala). Pityoborus, Gnatho- trichus, Conophthorus, and several Pityoph- thorus exhibited similar patterns of distribu- tion; for the most part, all breed in Pinus. The southeastern deciduous forest forms a distinctive faunal area. As evidenced by pres- ent relict refugia on the eastern margins of the Mexican plateau, this area formerly ex- tended southwestward into Mexico. Several Thysanoes, Cnesinus strigicollis LeConte, and Micracis swainei Blackman have present dis- tributions that follow this pattern. A few forms that apparently originated in this area, such as Micracisella nanuki (LeConte), M. opacithorax, and M. hondurensis Wood, have been modified by speciation. If the pines of the southeastern United States are considered to be part of the deciduous forest, Dendroc- tonus frontalis Zimmermann and the Ips that infest those pines and extend into Mexico are another example of this faunal connection. Southern Florida is distinctive and appears to be more nearly like Cuba or other Antilles Islands than like the southeastern United States in its scolytid fauna. A majority of the species appear to have reached the area re- cently by crossing over water naturally (flota- tion, wind, etc.) or through commerce. A high percentage of the imported species are first detected in North America in southern Florida. The scolytid fauna of the northern con- iferous forest is distinctive. For the most part, it is rather monotonous but exhibits some en- demism due to apparent refugia of past gla- cial periods in Alaska and Nova Scotia. Ele- ments of this fauna extend southward along the mountains of the eastern and western United States. The Pacific Coast belt from Alaska to southern California contains a rich fauna with many endemic species particularly in Phloeosinus, Carphoboriis, Ainiphagus, and Scohjtus. From this area many species appear to have migrated since the last period of gla- ciation into the mountains of Idaho, Wyom- ing, Utah, Colorado, New Mexico, and north- ern Arizona. Others, namely some Phloeosinus, Pseudopityophthorus agrifoliae Blackman, and Monarthrwn dentigerum (Le- Conte) have spread into Arizona at a time when the level of precipitation was higher than at present. Origin of Tribes In view of the above summary of data re- lating to the biogeography of American Scolytidae, perhaps some speculation as to the origin of major groups in the world fauna within the family is in order. This is based on the assumption that (1) a geologically recent Bering connection existed between Alaska and Siberia on more than one occasion, (2) Africa and South America were connected or at least were close enough to permit migra- tion by flight until the early Tertiary, and (3) South America was an island during most of the Tertiary, but was connected to North America near the beginning and near the end of that period and at one or more subsequent times. 52 Great Basin Naturalist Memoirs No. 6 Phrixosomini, Hypoborini, Micracini, Den- drocranulus (Dryocoetini), Acanthotomicus (Ipini), and parts of Xyleborini and Crypha- lini evidently originated in the African-South American land mass before separation. Phrixoscmia was probably then a relict genus rigidly adapted to the Guttiferae and has re- mained virtually unchanged in both areas since the separation. Micracini had diver- sified and the basic structure of most genera was almost fixed, as evidenced by paired or identical genera in both areas; diversification of the American segment of this group has been more extensive since the separation. Ctenophorini apparently also had a pre- separation origin, but the African segment became modified into modern Scolvtopla- typodini largely through the adoption of the ambrosial habit and then dispersed as far as Japan and Australia. The Diamerini-Both- rosternini may have had a preseparation ori- gin, but both diverged and diversified. Phloeotribini, Scolytini, and Corthylini ap- pear to have a postseparation South Ameri- can origin; all appear to have spread into North America at the beginning of the Ter- tiary and from there into Eurasia after the Tertiary. An early representative of Phloeotribini reached Australia, apparently from southern South America, possibly either by island hopping or flotation, resulting in the monotypic Aricertis. At a much later date Phloeotribus invaded North America and from there it reached Eurasia. The occur- rence of Pityophthorus (including aberrant al- lied forms) in Africa may indicate a slightly earlier origin for Corthylini; this group prob- ably reached North America by early Ter- tiary and Eurasia by late Tertiary. Phloeosi- nini may also have originated in the African- South American area but subsequent dis- persion has obscured the pattern. Because of repeated and recent con- nections to adjacent areas, the role of North America in the origin of tribal groups is un- certain, although it has played a significant role in the formation of generic groups with- in several tribes. A possible North American origin of Hylastini in the remote past is sug- gested but not clear. The role of Eurasia, the Indian subcon- tinent, and Africa (in addition to that mentioned above) is also unclear. The Polygraphini, Xyloterini, and Crypturgini probably originated in this area after the sep- aration of Africa and South America, or at least dispersal into South America did not oc- cur if there was a connection. The dispersal of Hylesinini, Tomicini, and Hypoborini, and many Dryocoetini, Xyleborini, and Crypha- lini is too complex to permit speculation as to origin. The representation of Hylesinini in North America is largely restricted to Hylesinus and Ainipliagus; both genera occur in adja- cent Asia and are obvious rather recent addi- tions to the North American fauna. Hylesi- nini is represented in Central and South America only by Phloeoborus, which is of an- cient origin and may be allied to the African Dactylipalpus. Hylastinus was introduced through commerce from Europe within the past century. Most of the Tomicini are restricted to hosts in the Pinaceae; consequently, their phyletic history is closely linked to that group. Excep- tions include Xylecliinns (part) (almost world- wide), Hylurgopiniis (North American), and Dendrotrupes (New Zealand). This appears to be a declining group that has undergone at least two radiations and is difficult to interpret. Except for Phloeosinus, the Phloeosinini consist of the essentially Neotropical Carpho- toreiis, Dendrosiniis, Chramesus, and Pseii- dochmmesus, the Ethiopian Chilodcndron, Hylesinopsis, and Trypograpfms, with Clodoc- tonus occupying both Ethiopian and Neo- tropical areas, the Oriental Phloeocranus, and the Australian Hyleops. Little relationship is seen in the group of genera from one conti- nent when compared to the group from an- other continent. Phloeosinus, however, ap- pears to be of south Asian origin and to have invaded Eurasia, North America, and Austra- lia perhaps as early as the early Tertiary. Except for the almost pantropical Acon- thotomkus, it appears that Ipini originated (from Acanthotomicus?) in southern Eurasia or Africa. The early stock invaded North America from the north, where Pityokteines and Ips formed while Pityogenes and Orthoto- tiiicus formed in Eurasia. One or more recent connections between the land masses enabled elements of each of these four genera to in- vade the territory of the other. In each case 1982 Introduction 53 the invaded area contains only a minor frac- tion of the species-groups, all of which are found in the area of origin (see also Extra- territorial Affinities, above). The Dryocoetini consist of several ele- ments, most of which are of south Asian ori- gin. Exceptions include Dryocoetes (sensu strictu) and Lymantor, which invaded north- em North America recently, and Dendrocra- nuliis, which recently invaded southern North America from South America, and Thamnurgus, Xylocleptes, Triotemnus, and possibly Tiarophorus of Eurasia and Africa. The origin of these latter groups evidently predates the separation of Africa and South America sufficiently that ancestral Den- drocranulus, which is almost congeneric with Xylocleptes, could disperse into South America. The Cryphalini appear to have subdivided early into the Cryphahis group of genera that radiated out from southern Asia and reached northern North America rather recently and the Hypothenemiis group of genera that radi- ated out from the African-South American land mass. A large number of genera and spe- cies are involved and cannot be adequately analyzed without a thorough taxonomic study. METHODS Several departures from normal procedure were followed in this study. Those relating to the examination of specimens include: (1) Early in this study it was learned that the published records of distribution and host could not be relied upon as being authentic. Consequently, virtually every record cited in this work was based upon my personal exam- ination of voucher specimens and types. Ex- ceptions are clearly indicated. Almost all ex- isting primary types, including the types of genera, have been examined by me and com- pared directly in detail to material from the same or a nearby locality. All type com- parisons are cited. Due to misidentification, numerous published distribution and host re- cords are not cited because they do not per- tain to the species mentioned in the liter- ature. Numerous collections were visited during the course of this study to obtain data and to examine type and other material. These included the National Museum of Nat- ural History (Smithsonian Institution), Ameri- can Museum of Natural History, Museum of Comparative Zoology, Illinois Natural His- tory Survey Collection, Ohio State University Collection, State University of New York, Syracuse, Oregon State University, University of California at Berkeley, Colorado State University, California Academy of Sciences, the USDA Forest Service Collections (at Cor- vallis, Oregon; Berkeley, California; Albu- querque, New Mexico; and Fort Collins, Col- orado), Canadian National Collection of Insects at Ottawa, British Museum (Natural History) at London, Museum National d'Histoire Naturelle at Paris, Universitates Zoologiska Museum at Helsinki, Zoological Institute of the USSR at Moscow, Forest Re- search Institute at Dehra Dun (India), and the Karl E. Schedl Collection at Lienz, Aus- tria. Type and other material was sent by mail for my examination from numerous in- stitutions and private individuals. Because many of these asked to remain anonymous, none are mentioned here. In all, more than 187,000 North and Central American speci- mens were examined during the course of the study. (2) Measurements of the length of speci- mens depart from the usual method in that the head was not included for any species (other workers have included the head for Hylesininae and Scolytini). In general, mea- surements of the body, pronotum, and elytra were made from a position perpendicular to the dorsal (discal) surface at a position near the middle of the object being measured. (3) All proportions were standardized; that is, the width was always divided into the length of the body, pronotum, or elytra (others have divided the shorter into the longer measurement regardless of the result). (4) Insofar as practical, the descriptions were standardized to make comparisons eas- ier and to avoid the illusion of describing dif- ferences when, in fact, none exist. (5) Distributions are presented just in a brief summary that outlines the most dis- tantly separated limits of range. This is then followed by a listing of political subdivisions from north to south beginning with Alaska (listed as though it were a separate country, due to its geographical position) to Panama. 54 Great Basin Naturalist Memoirs No. 6 Subdivisions of these political areas are listed alphabetically. When 10 or fewer collection records are known the full data are given; when 10 to 100 collection sites are known the towns or other localities are listed by states, estados, or provinces; when more than 100 sites are known only the names of the states, estados, or provinces are listed. (6) The authenticity of the data depends on the accuracy of locality, host identification, and labeling by the original collector; on the correctness of labeling in the laboratory; and on the absence of remounting errors and other accidents that can happen in the cura- tion of collections. Many errors have been published in the literature; a few of these were detected and eliminated or pointed out in this study. All my studies were made with a stereo- scopic American Optical Company micro- scope at magnifications of 10, 40, 80, and 160X, equipped with an ocular grid, using an American Optical Company illuminator Model 350, except at Moscow and Helsinki, where local museum equipment was used. Measurements were made in millimeters us- ing the ocular grid, only at lOX magnifica- tion, because distortion affected measure- ments at higher magnifications. Measurements of proportions not requiring conversion to millimeters were made at other magnifications also. When this study commenced it was in- tended that a complete listing of all known references to each species would be included. However, midway through the project finan- cial svipport for this activity was withdrawn and the literature review was discontinued. It is hoped that future events will permit the publication of this important omission. Only the original validation of each nominate spe- cies and the citation of new synonvmy were included. My usage of the terms "interspace" and "interstriae" are not svnonymous, as is the case with many coleopterists. Interspace here is a generic (general) term referring to a space between two objects, such as the space between any two punctures on the frons, pro- notum, or elytra. Interstriae is restricted to the space on the elytra between two strial rows. Because the space referred to can exist onlv between two striae, onlv the plural form of this term is valid. An interstriae is an inter- space, but only one restricted usage of inter- space is an interstriae. To avoid confusion in this work, aii interstriae is never referred to as an interspace. SYSTEMATIC SECTION Family Scolytidae ScoL\TARii Latreille, 1807, Genera crustaceonun et in- sectorum . . . 2:273 (Type-genus: Scolytus Geoffroy, 1762, see China 1962). The first noteworthy attempt to summa- rize the known information about the Scoly- tidae of North America was that of LeConte (1868), who treated 17 genera and 94 species. In a later summary he (LeConte 1876) in- cluded 26 genera and 123 species. Both re- views treated only the fauna of Canada and the United States. In his treatment of the fauna of Mexico and Central America, Bland- ford (1895-1906) recognized 4 tribes, 45 gen- era, and 270 species. Swaine (1918) treated the fauna of Canada and part of the United States, listing 4 subfamilies, 52 genera, and 226 species. In an uncritical summary of pre- vious work, Chamberlin (1939) listed 5 sub- families, 71 genera, and 571 species from Alaska, Canada, and the United States. Bright (1976) recognized 3 subfamilies, 45 genera, and 214 species in Alaska and Canada. The present study is the first attempt to treat the Scolytidae of all of North America, including Central America; 2 subfamilies, 20 tribes, 94 genera, and about 1430 species are listed. This represents an estimated 23 percent of the known world fauna. Speculation as to the apparent degree of completeness of our knowledge of the scoly- tid fauna of this area might be of interest in view of the experience that has resulted from the preparation of this work. It is supposed that 95-97 percent of the species in Alaska, Canada, and the United States are known. Those awaiting discovery will probably be sibling (cryptic) species that can be detected only through intensive biological studies or host specific species that breed in rare or un- studied hosts. Perhaps no more than 80-85 percent of the Mexican fauna is known; most undiscovered species there should be found in nonconiferous hosts. It is doubtful that as 1982 Introduction 55 much as 70 percent of the Central American fauna is known; unfortunately, the rapid rate at which natural habitats are being destroyed there may cause the extinction of many spe- cies before they are discovered by science. Since 37 foreign species have already been introduced into the area, additional species should be expected from this source and may already be established (Wood 1977). While I was engaged in a review of the various classifications of subfamilies and tribes for the Scolytidae by previous workers, it became apparent that they were based on only a minor segment of the family and could not adequately be used for the entire world fauna. In an effort to alleviate this deficiency, a new classification was proposed (Wood 1978) that was based on representatives of about 90 percent of known genera in the world fauna and that utilized characters not previously employed in scolytid classifica- tion. In addition, that contribution contains the first attempt, since priority at the family- group level became mandatory, to list sub- family and tribal names according to their priority. For these reasons the subfamily and tribal divisions may be somewhat different and the names selected less familiar than those presented by earlier works. The various groups are presented in the following key in as nearly a phylogenetic se- quence as present knowledge permits. Ob- viously, there is much opportunity for improvement. Key to Subfamilies, Tribes, and Genera- 1- Each basal margin of elytra procurved and armed (Fig. 16) by a series of marginal crenulations (or less commonly by a continuous elevated costa in some Bothrosternini and Diamerini), usually with a scutellar emargination between them; scutellum usually small and rounded or depressed, absent in some groups; pronotum weakly if at all declivous on anterior half, usually unarmed but crenulations sometimes present on anterolateral areas; head usually visible from above, somewhat wider; protibiae usually wider; scales or deeply divided setae a common feature; subfamily HYLESININAE 2 — Basal margins of elytra forming a straight transverse line across body, unarmed, rarely (some Scolytini, Ctenophorini, Cryphalini) with a weakly elevated continuous line (Fig. 17); scutellum usually large, flat (rarely absent or highly modified in some Xyleborini); pronotum weakly to strongly de- clivous on anterior half and usually armed by many asperate crenulations particularly on median half; head usually partly or entirely concealed from dorsal aspect, somewhat narrower; protibiae usually narrower; scales or deeply divided setae an uncommon feature; subfamily SCOLYTINAE 31 2(1). Scutellar area of metanotum and its postnotum separated by a suturelike in- tersegmental membrane (Figs. 18, 33 No. 43); posterior part of scutoscutellar suture strongly curved mesad to a point near costa or crest of scutellar groove then continuing cephalad parallel to this costa for about two-thirds length of metanotum (Fig. 18) (except much less in Phrixosomini and Hyorr- hynchini); metapleural suture descending subvertically from pleural wing process to metepisternal groove formed to receive corresponding costal groove and flage of elytron then abruptly angled and continued caudad along this groove to a point near pleural coxal process (Figs. 19, 33 No. 46); scutellum visible; fimicle 6-7-segmented or if 5-segmented (Sueiis, Oriental) then male frons not impressed and antennal club symmetrical 3 — Scutellar area of metanotum and its postnotum fused on at least median third, intersegmental suture obsolete (Figs. 21, 33 No. 42); scutoscutellar su- ture less strongly curved, approaching costa of scutellar groove more gradu- ally and continuing cephalad parallel to it for less than half length of me- tanotum (it never reaches margin of this groove in some groups) (Fig. 20); metapleural suture sometimes as described above, but more commonly run- ning a more direct route from pleural wing process to pleural coxal process, often remote from locked position of costal margin of elytra for most or all of its course; scutellum either not visible or if visible then funicle 5- segmented and male frons impressed (except Bothrosternini with 6-segmented funicle but with a distinctive protibia) 15 ■Included in the key are all subfamilies and tribes in the world fauna. The descriptions and distributions of genera apply only to the North and Central American fauna, .\dapted from Wood (1978). 56 1982 Key to Genera 57 HI 1' m r s Fig. 16. Phloeotribus setulosus: Posterolateral aspect of male, note crenulations on basal margins of elvtra, visible metepisternum, and pseudolamellate antennal club. Fig. 17. Scohjtock's plwneriac: Dorsolateral aspect of female. Fig. 18. Hylastes nigrinus: Dorsolateral aspect of nieso- and metatergimi with wings removed; note inter- segmental and scutoscutellar sutures (arrows). Fig. 19. Hylastes nigrinus: Lateral aspect of metapleuron (dorsal area at vipper left), note pleural sutures and groove on metepisternum that locks costal margin of elytron in place (arrows). Fig. 20. Hylastes nigrinus: Ventrolateral aspect of prothorax; note the costate precoxal ridge (arrow). Fig. 21. Eupagiocerus dentipes: Dorsal aspect of metatergum; note incomplete intersegmental suture (is), the com- pletely fused postnotum (pn), and the divergent scutocutellar suture (ss). 3(2). Eye entire to feebly emarginate; scutoscutellar suture parallel to costa of scutellar groove for two-thirds length of notum (Fig. 33 No. 43); precoxal ridge on prothorax present or absent; antennal funicle 5-7-segniented 4 — Eye completely divided by an einargination, halves widely separated; scu- toscutellar suture remote from costa of scutellar groove (Fig. 33 No. 41); cre- nulations on ba.sal margin of elytra low, often poorly formed; precoxal ridge on prothorax never present; antennal funicle usually 6-segmented (5- segmented in Oriental Sueus) 14 4(3). Prothoracic precoxal area rather large, its lateral margins strongly, sharply elevated from anterior margin to coxae (Fig. 20); crenulations on elytral bases usually poorly developed; antennal funicle 7-segmented, club conical, segment 1 about as long as others combined; head somewhat prolonged, sub- rostrate, frons never .sexually dimorphic (Fig. 14A); eye entire, rather short; Northern Hemisphere except introduced elsewhere; in Pinaceae (Tribe Hylastini) 5 58 Great Basin Naturalist Memoirs No. 6 — Prothoracic precoxal piece small, short, its lateral areas elevated or not; cre- nulations on elytral bases more conspicuously elevated, forming a definite row (except confused in Dactylopalpus, African); antennal funicle variable, 5-7-segmented, club weakly to moderately flattened; head less distinctly ros- trate, male frons usually impressed; eye oval to elongate, entire to feebly emarginate 7 5(4). Anterior coxae rather widely separated by an intercoxal piece, its width at least equal to half width of a coxa (as in Fig. 26); striae 9 and 10 both inde- pendently continued at least to level of abdominal sternum 4; elytral vesti- ture sparse, recumbent, yellow, hair- or bristlelike, never including scales; general surface of elytra and pronotum rather dull; body color reddish brown Scierus — Anterior coxae contiguous or at most with intercoxal piece narrower than one-fourth width of a coxa (as in Fig. 20 or 28); striae 10 obsolete behind level of posterior coxae, only striae 9 continues caudad; elytral vestiture longer, more abundant, usually including at least some small scales 6 6(5). Third tarsal segments broad, bilobed; pronotum usually constricted ante- riorlv, usually about equal numbers of small and large punctures intermixed on disc Hylurgops — Third tarsal segments narrower, emarginate; pronotum not noticeably con- stricted anteriorly, punctures uniformly large or small, rarely intermixed with a few small ones Hylastes 7(4). Pronotum asperate on anterolateral areas (except Hylastinus); pro thorax with strongly elevated costate ridge from coxa to anterior margin; antennal fimicle 6-7-segmented; mesal surface of elytra at base of suture immediately behind scutellum with an interlocking series of nodules and cavities (as in Fig. 22A-B), this lock interrupts groove and flange of suture (not visible when elytra in locked position); worldwide (Tribe Hylesinini) 8 — Anterolateral areas of pronotum unarmed; precoxal costa on prothorax ab- sent; funicle 5-7-segmented; mesal surface of elytra at suture with inter- locking groove and flange continued to base without a series of nodules or cavities immediately behind scutellum (Fig. 22C); worldwide (Tribe ToMICINl) 11 8(7). Anterolateral areas of pronotum unarmed by asperities; precoxal prosternum longer, its lateral margins from coxa to anterior margin strongly, acutely ele- vated, coxae more widely separated, intercoxal piece at least equal to half width of a coxa; eye entire; antennal club conical; breed in roots of clover .... Hylastinus — Anterolateral areas of pronotum usually armed by a few asperities; pro- sternum very short, its lateral margins obtusely, if at all, elevated, coxae more narrowly separated, intercoxal piece equal to less than one-fourth width of a coxa; breed in bark and wood of trees 9 9(8). Dorsal vestiture scalelike; eye rather short, entire; costal margin of elytra ascending toward apex; in Fraxinus Hylesinus — Vestiture hairlike; eye moderately long and shallowly emarginate to exceedingly elongate; costal margin of elytra descending toward apex 10 10(9). Antennal scape long, its apex attaining posterior margin of eye; eye com- paratively short, shallowly emarginate; length usually less than 4.0 mm; western USA and Canada; in Almis Alniphagus 1982 Key to Genera 59 Fig. 22 A-B. Pseudohijlcsinus n. nebuhsus: Mesal aspect of sutiiral margin at base of elytra; note that the sutural grooves continue to the base without interruption. Fig. 22C. Phloeosinits cristatus: Mesal aspect of sutural margin at base of elytra; note the interlocking cavities and nodules at the anterior end of the sutural grooves. — Antennal scape short, not attaining posterior margin of eye; eye exceedingly elongate, often siibcontiguous both dorsally and ventrally; usually larger than 8 mm; tropical species Phloeoborus 11(7). Antennal funicle 7-segmented, club conical, feebly flattened in a few species 12 — Antennal funicle 5-segmented, club moderately to rather strongly flattened 13 12(11). Vestiture scalelike; antennal club with segment 1 longer, usually about one- third of its total length; epistomal margin (and premandibular lobe, when present) with a small, median sulcus, sulcus usually ornamented by a few setae; western North America; in coniferous hosts Pseudohylesinus — Vestiture more slender; antennal club with segment 1 shorter, about one- fourth of its total length; epistomal margin continuous, without a median sulcus or setae; anterolateral area of pronotum with a few fine asperities; eastern North America; in Ulmus Hylurgopinus 13(11). Vestiture scalelike; area immediately above epistomal margin without an elevated epistomal process; smaller species Xylechinus — Vestiture hairlike; epistomal process well-developed; larger species Dendroctonus 14(3). Protibia armed on outer apical margin by several socketed denticles of ap- proximately equal size (as in Fig. 34); procoxae contiguous; frons convex, not sexually dimorphic; antennal scape elongate, suture 1 of club partly septate; pronotum never armed by asperities; America, Africa (Tribe Phrixosomini) Phrixosoma — Protibia with outer apical angle produced into one conspicuous spine reach- ing level of tarsal insertion, outer margin without any socketed teeth (as in Figs. 27 or 29); procoxae rather widely separated; male frons broadly im- pressed, female frons convex; antennal scape either long or short, club asep- tate; pronotum either with or without asperities in anterolateral areas; southeast Asia Hyorrhynchini 60 Great Basin Naturalist Memoirs No. 6 Fig. 23 A-B. Eupagiocerus dentipes: Posterior face of protibia: A, note the bifid outer apical process and B, the socketed lateral tooth. 15(2). Lateral margins of pronotum usually subacutely elevated, costate; mese- pimeron moderately to very large, its dorsal portion usually grooved for re- ception of elytral base; scutellar shield under base of elytra large, extending posteriorly beyond visible scutellum; scutoscutellar suture remote from costa of scutellar groove to its base; outer apical angle of protibia often with only one major, recurved spine; Africa, southeast Asia to Australia Diamerini — Lateral margins of pronotum usually rounded (subcostate in some neo- tropical Bothrosternini); mesepimeron not enlarged or grooved (feebly grooved in Aricerus, Australia); scutellar shield beneath elytra small if pres- ent, not extended caudad beyond visible scutellum; scutoscutellar suture near and parallel to costa of scutellar groove on at least anterior fourth of metanotum 16 16(15). Outer apical angle of protibia with a curved bifid process (Fig. 23), meso- and metatibiae with one or two (usually smaller) curved spines on outer apical angle extending beyond level of spine on inner apical angle; pro- notum smooth or longitudinally strigose; funicle 6-segmented; lateral pro- sternal area usually subacutely elevated from coxa to anterior margin; ante- rior coxae widely separated; crenulations on elytral bases rather small or (rarely) replaced by a continuously elevated costa; eye entire; America (Tribe Bothrosternini) 17 — Outer apical margin of protibia armed by several teeth of about equal size (except Aricerus in Phloeotribini, Australia), none of them extending beyond tarsal insertion; funicle 4-7-segmented; prosternal area with margins rounded, costa obsolete; eye varying from entire to emarginate to divided 21 17(16). Lateral margins of pronotum rounded 18 — Lateral margins of pronotum marked by a sharply elevated, costate to subcostate line (Fig. 24) 19 18(17). Sutures of antennal club transverse, straight; rostrum distinctly wider than distance between eyes; pronotum either longitudinally strigose or punctured; pith borers of twigs and woody vines Cnesinus 1982 Key to Genera 61 — Sutures of antennal club strongly procurved; rostrum width at tip equal to distance between eyes; frons excavated, with a median tubercle just above epistoma; body oval; seed borers Pagiocerus 19(17). Sutures of antennal club strongly procurved; pith borers in twigs and woody vines Eupagiocerus — Sutures of antennal club transverse, straight 20 20(19). Proepisternal area partly excavated, with cavity densely filled by yellow pubescence; prothoracic intercoxal piece with a transverse, subcarinate ridge; elytral interstriae usually not strongly carinate; ambrosia beetles in axial tunnels of woody vines Bothrosternus — Proepisternal area normal, not densely pubescent; prothoracic intercoxal ridge absent; elytral interstriae narrowly carinate from posterior part of disc to apex; pith borers in branches and twigs Sternobothrus 21(16). Scutellum visible, elytral bases notched for its reception; tarsal segment 3 stout, usually somewhat bilobed (except slender in Chramesus); mesal surface of elytra at suture immediately behind scutellum with a series on interlocking nodules and cavities 22 — Scutellum obsolete, elytral bases only slightly if at all emarginate at suture; tarsal segment 3 slender; mesal surface of elytra at suture usually without a special lock, groove and flange extend to base at position of scutellum 27 22(21). Antennal club pseudolamellate, strongly constructed at sutures and movable at intersegmental lines (Fig. 15); North and South America, Eurasia, Australia (Tribe Phloeotribini) Phloeotribus — Antennal club immovable, broadly fused at sutures, sutures often partly or entirely obsolete; worldwide (Tribe Phloeosinini) 23 23(22). Antennal funicle 6- or 7-segmented, club symmetrical, sutures transverse 24 — Antennal funicle 5-segmented, club moderately to very strongly asym- metrical, sutures oblique or absent 26 24(23). Antennal funicle 7-segmented, sutures on club procurved; body stout, black; basal area of pronotum strongly, rather extensively grooved for reception of elytral bases; abdomen ascending to meet elytra; larger species; tropical Dendrosinus — Antennal funicle 6-segmented; body more slender; basal area of pronotum not conspicuously grooved for reception of elytra; abdomen horizontal; smaller species 25 25(24). Eye entire; antennal club flattened, elongate, about equally divided by two strongly constricted, straight sutures; elytral ground vestiture rather abundant, subplumose Carphotoreus — Eye deeply emarginate; antennal club subglobular, recurved sutures in- dicated only by rows of fine setae; elytral ground vestiture sparse, mostly obsolete, hairlike when present Cladoctonus 26(23). Eye emarginate (completely divided in a few Indo-Australian species); an- tennal club marked by at least two oblique sutures, moderately asymmetric- al; tarsal segment 3 broad, somewhat bilobed; pronotum never armed by asperities; in coniferous hosts (mostly Cupressineae) Phloeosinus — Eye entire; antennal club large, strongly asymmetrical, sutures obsolete; tar- sal segment 3 slender; pronotum commonly with asperities in anterolateral areas; never in coniferous hosts Chramesus 62 Great Basin Naturalist Memoirs No. 6 27(21). Eye sinuate or entire; pronotum armed by a few scattered or clustered aspe- rities; crenulations at bases of elytra restricted to area between suture and interstriae 5; funicle 3-5-segmented; scutoscutellar suture remote from costa of scutellar groove on anterior fourth of metanotum; almost worldwide (Tribe Hypoborini) 28 — Eye emarginate or entirely divided; pronotum never armed by asperities; crenulations at bases of elytra more widely distributed, extending laterad beyond interstriae 5; funicle 5- or 6-segmented; scutoscutellar suture passing near and parallel to costa of scutellar groove on anterior fourth of metanotum; Northern Hemisphere, Africa (Tribe Polygraphini) 29 28(27). Antennal funicle 5-segmented, sutures of club transverse, distinct; elytral vestiture without conspicuous recumbent hair; pronotum armed by two or three widely separated, paired clusters of teeth Chaetophloeus — Antennal funicle 4-segmented, sutures of club indicated only by marginal notches; elytra with uniseriate rows of erect, broad interstrial scales and re- cumbent strial hair of equal length; pronotum armed by three or four pairs of median tubercles Liparthrum 29(27). Eye divided; elytral punctures very small, confused, strial rows not evident; antennal club without sutures; antennal funicle 5- or 6-segmented Polygraphus — Eye emarginate; strial rows clearly indicated by rows of coarse punctures; antennal club with sutures clearly marked 30 30(29). Antennal funicle 6-segmented; elytral ground vestiture hairlike; on Cupressinae Carphobius — Antennal funicle 5-segmented; elytral ground vestiture scalelike; on Abietineae Carphoborus 31(1). Lateral margin of pro- and metatibiae unarmed except for a single, apical, spinelike process that curves toward and extends beyond process of inner apical angle; lateral margin of pronotum subacutely elevated, costate (Fig. 25); pleural suture descending subvertically from pleural wing process to groove receiving groove and flange on costal margin of elytra, at this point suture turns abruptly and follows groove caudad to metapleural coxal pro- cess (Fig. 25); funicle 7-segmented, sutures of antennal club strongly procurved or obsolete; Holarctic and Neotropical (Tribe Scolytini) 32 — Lateral margin of protibia armed by more than one denticle, none of which exceed or curve toward inner apical process; pleural suture less strongly ang- ulate, groove receiving flange of costal margin of elytra displaced ventrad from course followed by pleural suture; lateral margin of pronotum subacutely raised or not, antenna variable 35 32(31). Scutellar area of interstriae 1 not depressed, scutellum even (flush) with ely- tral bases; basal margins of elytra with a fine raised line (broken into minute crenulations in some Cnemonyx), outline of anterior margins form a contin- uous, straight, transverse line with scutellum; ventral profile of abdomen ascending gradually 33 — Scutellum depressed, subtriangular, apically (posteriorly) pointed; elytral bases depressed in scutellar area, appearing emarginate in median area; ventral profile of abdomen usually ascending abruptly at segment 2 34 1982 Key to Genera 63 33(32). Antennal club usually with two or three sutures clearly marked by setae; scutellum small, longer than wide, often convex; apical margin of meso- and metathoracic tibiae commonly bearing tubercles on anterior edge in addi- tion to inner and outer processes; usually more coarsely sculptured, smaller species, less than 2.5 mm; phloeophagous Cnemonyx — Antennal club with only suture 1 marked internally by a partial septum; scu- tellum flat, 1.5 or more times as wide as long; meso- and metathoracic tibiae acutely margined on apical anterior edge, without supplemental denticles; usually very finely sculptured; 2.2-8.5 mm; xylophagous ambrosia beetles Catnptocerus 34(32). Humeral margin of elytra deeply, broadly excised, metepisternum con- spicuously expanded into this notch; abdomen abruptly flexed upward at posterior margin of segment 2; phloeophagous; tropical Scolytopsis — Humeral margin of elytra normal (straight) and overlapping metepisternum; abdomen flexed upward from anterior margin of segment 2; phloeophagous . Scolytus 35(31). Metepisternum visible throughout its length, slightly more than its dorsal half covered by elytra when in locked position, either with a conspicuous groove for reception of costal flange throughout its length or else groove represented at its anterior end by a denticulation or costate remnant near anterior end of metepisternum; antennal club varying from flat to obliquely truncate 36 — Metepisternum largely covered by elytra, its groove for reception of costal flange obsolete, a small, transverse callus (Cryphalini) (Fig. 31) or a small transverse groove (Corthylini) (Figs. 32 or 33:47) at anterior end of mete- pisternum; antennal club strongly flattened; antennal club never obliquely truncate 70 36(35). Lateral margins of pronotum subacutely elevated, basal margin of elytra usually finely elevated (Fig. 16); procoxae rather widely separated (Fig. 26) except contiguous in Xyloctonini (Africa to SE Asia); protibia with promi- nent outer apical process recurved, usually extending beyond tarsal insertion (Fig. 27), posterior tibia tapered on apical third and armed by several small socketed denticles; funicle 6-7-segmented; tarsi often retractile into tibial grooves 37 — Lateral and basal margins of pronotum rounded; procoxae subcontiguous (Fig. 28) (except most Micracini and a few Xyleborini); protibia with outer apical angle inconspicuous, armed by several small socketed denticles; funicle 2-6-segmented; tarsi not retractile (except Xyleborini) 42 37(36). Eye divided or nearly so by a very deep emargination; antennal club flat, usually enlarged, with sutures strongly procurved; abdomen conspicuously ascending toward apex (not always clear in Ctonoxylon, Africa); tarsi always retractile into tibial grooves; Africa, SE Asia Xyloctonini — Eyes entire to shallowly sinuate on anterior margin; antennal club flat, usu- ally smaller, more slender, sutures variable if present; abdomen horizontal; tarsi retractile or not 38 38(37). Antennal club unmarked by sutures; pronotum with sides strongly con- stricted on posterior half; scutellum absent (a small scutellum present in one species); Africa to Asia, New Guinea (Fig. 30); mycetophagous SCOLYTOPLATYPODINI Great Basin Naturalist Memoirs No. 6 Fii^. 24. Eiipu^iocerus dcntipea: Lateral aspect; note the costate lateral margin of the pronotnm. Fig. 25. Cnemonijx panamcn.sis: Lateral aspect, wings removed; note the costate lateral margin of the pronotum. pleural suture, and groove for reception of elvtra. Fig. 26. Scoli/todes phtmcriae: Ventrolateral aspect: note costate lateral margin of pronotum. visible mete- pisternum, and interstriae 10 (arrow) that extends to posterior third of elytra. Fig. 27. Scolytodes schwarzi: Posterior face of i)rotil)ia; note lateral unsocketed spine extending beyond inner (mesal) apical spine (arrow). — Antennal club with one or more .sutures indicated by grooves, setae, or sep- tae; scuteUum large, flat; America; not mycetophagous (Tribe Ctenophorini) 39 39(38). Eyes elongate, approximate above and below, coarsely faceted, .shallowly emarginate; entire surface of pronotum .smooth and punctured, not armed 40 — Eye oval, entire, finely faceted; pronotum asperate anteriorly or if smooth then anterior margin of elytra bearing a fine raised line 41 40(39). Antennal club subglobular, about as long as wide, sutures not clearly in- dicated; pronotum longer than wide, its lateral margins straight or feebly constricted; vestiture hairlike, usually sparse; small, slender species Microborus 1982 Key to Genera 65 — Antennal club asymiiietrically flattened, pointed, at least 1.5 times as long as wide, sutures 1 and 2 clearly marked by setae; pronotum wider than long, its lateral margins arcuate; vestiture of abundant, short, bristlelike scales; larger, stouter species Pycnarthrum 41(39). .\ntennal funicle 7-segmented, club large, broad, usually with procurved su- tures or sutures obsolete; elytral vestiture consisting of abundant, minute hair and sparse interstrial rows of long, erect, scalelike bristles; summit of pronotum on basal third, asperities on anterior area coarse; elytral base without a fine raised line Gymnochilus — Antennal funicle 6-segmented, club small, sutures present or not; elytral ves- titure sparse, hairlike; asperities fine, if present; summit at middle or in- definite; basal margins of elytra marked by a fine raised line (Fig. 16) Scolytodes 42(36). Procoxae moderately separated; protobiae with sides parallel, armed by den- ticles only on apical margin or posterior face; funicle 6-segmented; female frons often concave, male frons rarely concave (two Pseudothysanoes); Africa, America (Tribe Micracini) 43 — Procoxae contiguous (except Carphodicticini, some Xyleborini); protibia much wider apically, armed on lateral margin by several denticles; female frons rarely concave (a few Dryocoetini), male frons often concave; funicle 2-5-segmented 49 43(42). Elytra broadly rounded behind (subacuminate in Pseudothysanoes mucro- natus); lateral margins of antennal club constricted at sutures 1 and (usually) 2, except when sutures totally obsolete 44 — Elytral apices acuminate (partly lost in some Micracisella), usually mucro- nate; antennal club without sutural constrictions, sutures always indicated on anterior face 46 44(43). Pronotum longer than wide, summit less strongly developed; protibia rather broadly flattened, sides parallel, subtruncate apically Thysanoes — Pronotum as wide or wider than long, summit well developed; protibia slender, weakly or not at all flattened 45 45(44). Elytral declivity in both sexes variously sculptured but never sulcate; anten- nal scape long or short, club with or without sutures; mostly phloeophagous, a few xylophagous Pseudothysanoes — Elytral declivity bisulcate, subvertical; antennal scape short, flattened, little if any longer than pedicel, club small, widest through basal half, sutures 1 and 2 straight, indicated by rows of setae; phloeophagous Stenocleptus 46(43). Eye short, oval, not more than 1.5 times as long as wide, finely faceted; an- tennal club small, sutures straight to weakly procurved or bisinuate; protibia slender 47 — Eye elongate, 2.0 or more times as long as wide, coarsely faceted; antennal club rather large, sutures very strongly procurved; anterior tibiae rather strongly flattened 48 47(46). Sutures 1 and 2 on antennal club straight, visible only at margins, obsolete in central area, club small; protibia entirely unarmed on posterior face, smooth; phloeophagous Phloeocleptus — Sutures 1 and 2 on antennal club weakly procurved to bisinuate, clearly vis- ible in central area of anterior face, club larger; protibia armed on posterior face by many tubercles or rugae; xylophagous Hylocurus 66 Great Basin Naturalist Memoirs No. 6 48(46). Eye shallowly emarginate, often approximate below; anterior tibiae less strongly flattened, at least one of five distal teeth on outer margin; scape usually less strongly expanded; antennal club rather broad, sutures more broadly procurved; monogamous, pith beetles Micracisella — Eye entire, always widely separated below; anterior tibia more strongly flat- tened, all five teeth on distal margin; scape usually very strongly expanded; antennal club more elongate, sutures usually much more strongly, narrowly arcuate; bigamous, xylophagus Micracis 49(42). Male frons strongly excavated, epistoma armed by a pair of (usually) fused spinelike horns of enormous size; funicle 5-segmented, club often small and feebly flattened; eye small, entire; pronotum with summit near basal margin, projecting back over scutellum in some species; western United States and Mexico (Tribe Cactopinini) Cactopinus — Not fitting above combination of characters 50 50(49). Meso- and metathoracic tibiae more slender, more abruptly narrowed on apical fourth, lateral and apical margins armed by fewer, coarser teeth; eye sinuate to shallowly emarginate (divided in Tiarophorus, Dryocoetini, Af- rica); pronotum sometimes with a raised line on basal or lateral margin; pregular area not depressed; sexes of similar size and body form (except male dwarfed and deformed in Coccotrypes and Ozopemon); habits varied but never woodboring or mycetophagous 51 — If eye completely divided into two parts and antennal funicle 4-segmented then male frons deeply excavated and male equal in size to female; if eye emarginate (or if divided and funicle 5-segmented) then male dwarfed, de- formed, and flightless and female meso- and metathoracic tibiae expanded to just beyond middle then arcuately tapered to apex, its apical two-thirds on outer margin armed by a row of numerous small, closely set teeth of equal size, these usually supplemented in same row by submarginal hair on poste- rior face; male pronotum highly modified; pregular area depressed (except Premnobius); woodboring, mycetophagous 62 51(50). Pronotum rather strongly, laterally constricted on posterior half, anterior half not declivous and unarmed by asperities; anterior coxae moderately sep- arated; antennal club strongly flattened, marked by two sutures, sutures on posterior face almost equal to those on anterior face; South America, India to Ceylon Carphodicticini — Pronotum not constricted, sides straight to arcuate, anterior half declivous, usually armed; anterior coxae contiguous; antennal club obliquely truncate (Fig. 29) or with sutures on posterior face strongly displaced toward apex (rarely with sutures obsolete) 52 52(51). Elytral declivity moderately sulcate to elaborately excavated, with lateral margins usually armed by tubercles or spines; pronotum more strongly declivous on anterior third, asperities usually larger; worldwide (Tribe Ipini) .... 53 — Elytral declivity slightly flattened to convex, unarmed by tubercles, spines, or unusual sculpture; pronotum usually evenly arched from base to anterior margin; asperities fine and abundant when present 57 53(52). Elytral declivity rather narrowly bisulcate, lateral margins rather broadly elevated, rounded, and armed by not more than three pairs of denticles; lower margin of declivity rounded; usually smaller than 3 mm 54 1982 Key to Genera 67 — Elytral declivity broadly, rather deeply excavated, margins acutely elevated and armed by three or more pairs of denticles (except one to six in tropical Acanthotornicus); lower margin of declivity with an acutely elevated trans- verse ridge separating declivital excavation from apical margin; usually larger than 3 mm 55 54(53). Prosternal intercoxal piece short, obtuse; female frons deeply, rather narrow- ly excavated (except meridianus and mexicanus); male declivity with two or three pairs of enlarged denticles; antennal club compressed, two sutures visible on distal third of posterior face Pityogenes — Prosternal intercoxal piece long and acutely tapered; female frons convex; male declivity more narrowly impressed Pityokteines 55(53). Antennal club obliquely truncate, sutures recurved; third (lowest) major den- ticle not on lateral margin of elytral declivity, displaced mesad from margin; eye of normal size; in coniferous hosts Orthotomicus — Antennal club flattened, sutures either procurved or strongly bisinuate; lat- eral margin of elytral declivity armed by one to six major denticles, third (if present) on or incorporated into crest of lateral margin; eye usually abnormally large or else very small 56 56(55). Sutures of antennal club (when present) moderately to very strongly pro- curved; eye large, very coarsely faceted, its width about equal to length of scape, its length more than twice length of scape; in angiosperm hosts from Mexico to South America Acanthotomicus — Sutures of antennal club moderately to strongly bisinuate (except procurved in concinnus, mexicanus); eye small, finely faceted, its width equal to much less than length of scape, its length equal to much less than twice length of scape; in coniferous hosts from Canada to Nicaragua Ips 57(52). Antennal funicle 4-6-segmented, club either obliquely truncate or with su- tures on posterior face strongly displaced toward apex; anterior half of pro- notimi more strongly declivous and rather coarsely asperate (unarmed in Tiarophorus, Africa); worldwide (Tribe Dryocoetini) 58 — Antennal funicle 2-3-segmented, club with sutures on posterior face about equal to those on anterior face; pronotum feebly declivous on anterior half and unarmed (minutely granulate in some Aphanarthrum, Africa, etc.), reti- culate in many species; size small; Northern Hemisphere, Africa (Tribe Crypturgini) 61 58(57). Pronotum distinctly longer than wide, widest at middle; antennal club com- pressed or with membranous apical portion extending beyond corneous portion, sutures procurved; scutellum very small 59 — Prothorax about as wide as long, widest on posterior third, sides converging rather strongly on anterior half; antennal club obliquely subtruncate, sutures transverse or recurved; scutellum moderate to large 60 59(58). Antennal funicle 4-segmented; club compressed, sutures strongly arcuate; pronotum granulate on anterior half, punctured behind; host Acer Lymantor — Antennal fimicle 5-segmented; club less strongly compressed, sutures nar- rowly to rather broadly procurved; pronotum usually granulate to base; host Cucurbitaceae Dendrocranulus 60(58). Antennal club with basal corneous portion reaching beyond middle; declivi- ty steep, abrupt, confined to posterior fourth of elytra; northern North America; in coniferous hosts Dryocoetes 68 Great Basin Naturalist Memoirs No. 6 — Corneous portion not reaching middle of antennal club in central area; de- clivity gradual, extending over at least posterior third of elytra; frons con- vergently aciculate; southern USA to South America; in nonconiferous hosts Coccotrypes 61(57). Antennal fvmicle 2-segmented, club with one suture near apex; northern and eastern North America Crypturgus — Antennal funicle 3-segmented, club with three sutures; northwestern North America Dolurgus 62(50). Eye always completely divided into two parts; antennal funicle 4-seg- mented, base of club feebly to moderately corneous, usually pubescent to base; male subequal in size to female, his frons flattened or excavated and anterior margin of his pronotum more broadly rounded; male joins female in parental gallery, reproduction always bisexual; Europe, Asia, North America (Tribe Xyloterini) 63 — Eye emarginate except divided in some Pseudoxyleborus (SE Asia); funicle 5- segmented (3- or 4-segmented in a few Asiatic forms); males flightless, dwarfed, deformed, anterior slope of pronotum variously excavated; male head convex; male absent from parental gallery except as progeny; partly parthenogenetic, males haploid; worldwide (Tribe Xyleborini) 64 63(62). Subcomeous basal area of antennal club broadly, feebly procurved; anterior tibiae flattened, devoid of tubercles on posterior face in both sexes; male frons somewhat flattened; male distinctly smaller than female; long axis of female proepimeral excavation transverse Xyloterinus — Subcomeous basal area of antennal club strongly, narrowly procurved; fe- male protibiae inflated and tuberculate on posterior face, flattened and tu- berculate in male; male frons deeply, extensively, concavely excavated, con- vex in female; male pronotum subquadrate, its anterior margin unarmed and straight to weakly recurved, in female serrate and procurved; long axis of female proepimeral excavation longitudinal, very narrow Trypodendron 64(62). Pregular area not depressed below surrounding ventral area of head; labial palpi cylindrical, comparatively slender; antennal club thickened at base, margin of thickened area procurved, not corneous, pubescent almost to base; lateral margin of pronotimi subacute from base almost to anterior margin; posterior face of protibia minutely tuberculate; anterior margin of pronotum imarmed Premnobius — Pregular area depressed inward below ventral contour of head; labial palpi broad, segment 1 greatly enlarged; antennal club usually obliquely truncate, basally corneous, sutures if present recurved (except Sa7npsonius); lateral margins of pronotum more broadly rounded; protibiae usually smooth on posterior face (except Dryocoetoides); anterior margin of pronotum armed or not 65 65(64). Antennal club often more strongly flattened, with two transverse or pro- curved sutures not attaining margins laterally but continuing separately, su- ture 1 continuing to and clearly visible on posterior face, suture 2 continuing to apex of club or more rarely to posterior face near apex, basal area more weakly corneous, both sutures equally elevated; anterior margin of pronotum always serrate 66 — Antennal club clearly, obliquely truncate, basal area strongly corneous, its distal margin on anterior face recurved, usually acutely marked, continuing to apex of club, a second suture sometimes indicated but entirely confined to anterior face, usually obsolete before apex and never acutely elevated; anterior margin of pronotum serrate or not 68 1982 Key to Genera 69 66(65). Antennal club rather strongly flattened, both sutures moderately to rather strongly procurved; pronotum very slender, at least 1.4 times as long as wide, its anterior margin armed by two very coarse serrations; elytra very elongate, declivity gradual and as long as disc, ordinarily with unusual sculp- ture and ornamentation; eyes very large, very coarsely faceted; tropical Sampsonius — Antennal club with sutures straight, feebly procurved to weakly recurved; pronotum stout, less than 1.1 times as long as wide, its anterior margin usual- ly armed by four or more moderately coarse serrations; elytra variously sculptured, moderately elongate 67 67(66). Anterior tibia inflated and armed on posterior face by several conspicuous, confused granules or denticles in addition to socketed teeth on outer margin; eyes averaging larger and more coarsely faceted Dryocoetoides — Anterior tibia flattened, its posterior face smooth, entirely devoid of granules; eyes averaging smaller and more finely faceted Theoborus 68(65). Anterior coxae widely separated by an intercoxal piece; body very stout, 1.9-2.3 times as long as wide; anterior margin of pronotum serrate; elytral disc occupying less than half of elytral length, declivity convex, devoid of major tubercles or processes Xylosandrus — Anterior coxae contiguous; body stout to slender, elytra variously sculptured .... 69 69(68). Basal margins of elytra rounded, forming an almost straight, transverse line across body; scutellar notch entirely filled by scutellum; scutellum flat, attaining level of elytral surface Xyleborus — Basal margins of elytra abrupt, precipitous in median area; scutellum con- ical, not filling scutellar notch, adjacent vertical sides of scutellar notch pub- escent; posterolateral margin of elytral declivity often dentate, never carinate Xylehorinus 70(35). Costal margin of elytra slightly to moderately ascending from base of decliv- ity to apex; basal end of metepisternum armed by a callus or partial groove of degenerating metepisternal spine (Fig. 31); sutures on posterior face of antennal club more strongly displaced toward apex; funicle 3-5-segmented; tibiae more strongly flattened, usually armed by more than four denticles; vestiture commonly includes scales; eye usually entire, less commonly emarginate; worldwide (Tribe Cryphalini) 71 — Costal margin of elytra descending toward apex (except Brachyspartus, South America); basal end of metepisternum with a small, transverse groove (Fig. 32) (concealed when elytra in locked position), elytra in locked position more completely cover metepisternum; sutures on posterior face of antennal club only slightly displaced toward apex; funicle 1-5-segmented; tibiae more slender, rarely armed by more than four socketed denticles; vestiture rarely includes scales (in tropical forms only); eye emarginate; almost worldwide except Australia (Tribe Corthylini) 80 71(70). Lateral margins of pronotum without a fine, raised line (indistinct in Scoly- todes); eye sometimes sinuate, emarginate only in Stegomerus; costal margins ascending only slightly posteriorly 72 — Lateral margins of pronotum acute, at least basally, and with a fine raised line on basal third; eye emarginate (except Trischidias); costal margins of elytra ascending distinctly posteriorly 76 70 Great Basin Naturalist Memoirs No. 6 Fig. 28. Ips woodi: Ventral aspect of prothorax; note contiguous coxae (right coxa removed) and the absence of a precoxal ridge. (Plant fiber between coxae is an artifact.) Fig. 29. Dnjocoetes confusus: Anterior aspect of antenna; note the obiicjueiy truncate apical face of club. Fig. 30 A-B. Scolytoplatypus papuanus. A, Posterior aspect of protibia; B, note that lateral denticles are not socketed. Fig. .31. Cryphalus nifirollis nifirollis: Dorsal aspect of parts of thorax with wings removed; note pronotal aspe- rities and the degenerate episternal spine (arrow) that locks costal margin of elytra in position. Fig. .32. Corthyhts panatncnsis: Lateral aspect of metathorax with elytra removed; note loss of episternal groove and spine and its replacement by a small, oblique, anterior groove (arrow) and the very different position of the pleural suture (arrow). 1982 Key to Genera 71 Fig. 3.3. Diagrams of Stolytidae metanota: 41, Chramesiis liickoriae dorsal aspect (arrow points to remnant of in- tersegmental suture; 42, same, pleuron (arrow at metepisternal spine; 43, Hylasfes nigrinus dorsal aspect, with labels indicating intersegmental suture (is), postnotum (pn), scutellar groove (sg), and scutoscutellar suture (ss); 44, same, lateral aspect, with labels at metepimeron (mn), metepisternum (ms), pleural suture (ps), and metepisternal spine (s, marked by arrow); 45, Cnctnomjx panamensis, dorsal aspect (arrow points to intersegmental suture); 46, same, lateral aspect (arrow points to metepisternal spine); 47, Pityophthorus croionis. lateral aspect (arrow points to metepisternal groove that has replaced the spine of other tribes), (.\ftcr Wood 1978.) 72(71). Antennal club slender, 1.7-2.2 times as long as wide, apically pointed, su- tures aseptate, straight; antennal funicle 5-segmented; basal half of pronotum without scalelike setae; on Alnus, Populus, Salix Trypophloeus — Antennal club wider, less than 1.6 times as long as wide, apically rounded, sutures almost straight or procurved, often septate; funicle 4- or 5-segmented; basal half of pronotum with some scalelike setae 73 72 No. 6 Fii;. 34. Apex of posterior face of protlioracic- tibia of Pohjgmphus rufipcnnis showing socketed denticles at margin. 73(72). Antennal club with three moderately to .strongly procurved, aseptate sutures marked by rows of setae 74 — Antennal club with suture 1 at least partly septate, .sutures either straight or else not marked by rows of setae 75 74(73). Antennal funicle 5-segmented; eye shallowly, broadly emarginate; tropical ... Stegomerns — Antennal funicle 4-.segmented; eye entire; eastern USA Ernoporicus 75(73). Sutures of antennal club straight, suture 1 septate; anterior margin of pro- notum slightly produced; lateral areas of pronotum with no indication of a raised line; northern North America Procryphalus — Suture 1 indicated only on lateral half of antennal club by a strongly ang- ulate septum, other sutures and median half of 1 obsolete; anterior margin of pronotum broadly rounded; lateral margins of pronotum rounded and marked by a fine, raised line; tropical Scolytogenes 76(71). Antennal club with sutures recurved, suture 1 aseptate; tarsal segment 3 broad and emarginate; American species only in coniferous hosts Cryphalus — Antennal club with sutures straight or procurved; tarsal segment 3 cylindrical; rarely in coniferous hosts 77 77(76). Antennal funicle 5-segmented, club large, with three aseptate, procurved su- tures; strial punctures obsolete; male and female equal in size and appear- ance; vestiture abundant; monogamous and phloeophagous Hypocryphalus — Antennal club smaller, suture 1 often septate, funicle often with reduced segmentation, male dwarfed, much smaller than female, with eyes abnormally small, flightless, rare; pith beetles, some phloeophagous 78 78(77). Eye entire; club rather large, aseptate, fimicle normally 3-segmented, rarely 4-segmented; body very stout, less than 2.3 times as long as wide, smaller than 1.1 mm; SE USA Trischidias — Eye emarginate; funicle 5-segmented, less conunonly 4-segmented (some- times 3-segmented in Hypothenemus bimianns or males of any species); iLsuallv larger and more slender 79 1982 Key to Genera 73 79(78). Aiitennal club with suture 1 partly septate; raised lateral line extending only one-third pronotum length from base; elytra clothed with rows of rather abundant strial and interstrial setae; mature color usually dark brown to black Hypothenemus — Antennal club aseptate; raised lateral line extending two-thirds pronotum length from base; subglabrous, a few subspatulate interstrial bristles on de- clivity; mature body color usually rather pale yellowish or reddish brown Cryptocarenus 80(70). Antennal fimicle usually 5-segmented (3- or 4-segemented in Dendroterus, Dacnophthorus), club asually smaller, symmetrical; prosternal intercoxal piece acutely pointed (except Dacnophthorus); pubescence usually more abundant, usually in rows on elytra; elytral declivity convex to bisulcate, armature conservative; bark and twig beetles (Subtribe Pityophthorina) 81 — Antennal funicle 1- to 5-segmented, club usually much larger, commonly asymmetrical prosternal intercoxal piece absent (except obtuse in Gnatho- triclms, Gnathotrupes); pubescence usually greatly reduced to obsolete or minute and strongly confused; elytral declivity convex to truncate to deeply excavated (weakly bisulcate in some Gnathotrichus), commonly with spinose processes; ambrosia beetles (Subtribe Corthylina) 92 81(80). Basal and lateral margins of pronotum rounded, devoid of a fine, raised line; elytra rather coarsely punctured, unarmed declivity steep, usually sub- vertical and somewhat flattened on lower half, almost never bisulcate; discal vestiture abundant 82 — Basal and lateral margins of pronotum marked by a finely raised line; elytral declivity more gradual, convex to bisulcate, often ornamented by granules 83 82(81). Antennal funicle 5-segmented, club with aseptate sutures strongly pro- curved; interstrial setae scalelike; male frons strongly, transversely carinate at upper level of eyes, female epistoma deeply emarginate to accommodate a pair of mandibular spines Styphlosoma — Antennal funicle 3- or 4-segmented, club with sutures at least slightly re- curved, aseptate; elytral vestiture hairlike; female epistoma not emarginate, mandible never with projecting spines Dendroterus 83(81). Sutures of antennal club moderately to very strongly procurved, only suture 1 septate, or if all external sutvires obsolete then mesal half of suture 1 marked by an internal septum Araptus — Sutures 1 and 2 clearly, equally marked by rows of setae and grooves, straight to moderately procurved, if procurved then both sutures at least partly septate (sutures straight when both almost obsolete) 84 84(83). Sutures 1 and 2 of antennal club aseptate and clearly marked by grooves and rows of setae; pronotal asperities continuing in lateral areas to base; larger species; in cones oi Piniis (except hanksianae in twigs) Conophthorus — Sutures 1 and 2 both partly to completely septate or if aseptate then either antennal club largely glabrous or body size much smaller; pronotal asperities not extending to basal margin except in some tropical species not found in coniferous hosts; mostly smaller species; never in cones of conifers 85 85(84). Pronotum without a transverse impression behind summit, transition from asperate to punctured areas gradual or asperities continuous to base; rare tropical species 86 74 Great Basin Naturalist Memoirs No. 6 — Pronotum with a distinct transverse impression behind summit (a few excep- tions in Pityojyhthorus), transition from asperate to punctured area more abrupt 87 86(85). Elytral vestiture hairhke; elytral declivity broadly, subconcavely impressed; larger species Conophthocranulus — Interstrial setae scalelike (spatulate), in rows; elytral declivity convex; male frons armed Spermophthorus 87(85). Sutures of antennal club moderately procurved, segment 1 shorter than 2 or 3; greater frontal pubescence a male character; elytral punctures fine, usual- ly confused, short pubescence abundant, often scalelike, striae usually obsolete; mostly confined to Quercus; bigamous Pseudopityophthorus — Sutures of antennal club straight to weakly procurved, segments 1 and 2 sub- equal in length; pubescence never scalelike, less abundant, striae clearly evi- dent or if confused than punctures rather coarse; almost never in Quercus (exceptions are tropical) 88 88(87). Antennal club rather large, 2.5 or more times as long as funicle; monogamous 89 — Antennal club proportionately smaller, usually less than 1.5 times as long as funicle; polygamous (except a few Pityophthorus) 90 89(88). Body stouter, 2.5-2.8 times as long as wide; elytral declivity convex; female pronotum with a pair of large, densely pilose areas in anterolateral areas; antennal club with only two sutures; in Pinus Pityohorus — Body very slender, 3.7-3.8 times as long as wide; elytral declivity strongly impressed; female pronotum without pilose areas; antennal club with suture 3 indicated by a row of setae; in Clematus and other vines; tropical Dacnophthorus 90(88). Female head normal, pregula and mandibles not disproportionately enlarged; antennal funicle usually 5-segmented Pityophthorus — Either female pregula greatly enlarged and bearing a tuft of hair or else female oral region abnormally broad and with mandibles greatly enlarged 91 91(90). Female pregula greatly enlarged and bearing a tuft of long hair, male pregula only slightly enlarged; Arizona and New Mexico; in Pinus Pityotrichus — Female oral region abnormally broad and with mandibles greatly enlarged; Costa Rica to Brazil; in broadleaf trees Gnatholeptus 92(80). Antennal funicle 5-segmented, club always symmetrical, with two or three clearly marked sutures; anterior tibia widest near apex, its posterior face usually flat, unarmed (a few minute granules in Gnathotrupes); elytral declivity conservatively sculptured 93 — Antennal funicle 1- to 3-segmented, club commonly asymmetrical, sutures often reduced or absent; tibiae variously sculptured; declivity frequently armed 94 93(92). Sutures of antennal club straight to moderately procurved, segment 1 not noticeably reduced in size; elytral declivity convex to narrowly sulcate, sub- apical margin near apex acutely elevated, sutural apex entire, rather narrowly rounded behind; Canada to Costa Rica Cnathotrichus 1982 Key to Genera 75 — Sutures of antennal club moderately to strongly procurved, segment 1 dis- tinctly smaller; elytral declivity moderately to strongly flattened; elytral apex at least weakly divaricate, very broadly rounded to shallowly emargi- nate behind, without a submarginal costa near apex; Guatemala to South America Cnathotrupes 94(92). Antennal funicle 2- to 3-segmented, club with two sutures clearly marked; elytral apex divaricate (except Metacortlnjius, Glochitwcenis), commonly ex- planate, declivity often elaborately excavated and armed by spines; protibia always slender, with posterior face inflated and tuberculate; body usually slender 95 — Antennal fimicle 1 -segmented, club with one, two or no sutures; elytral apex entire, declivity convex to rather weakly excavated, never explanate; pro- thoracic precoxal piece transverse, straight, not extended between coxae; protibiae variable; body comparatively stout 99 95(94). Procoxae contiguous, anterior wall of combined coxal cavities and precoxal piece transversely straight; protibiae similar in male and female, with mar- ginal row of tubercles, posterior face either unarmed or with a longitudinal row of up to about four tubercles; posterior face of female antennal club with long hair sparse to absent; antennal funicle usually 3-segmented, less commonly 2-segmented; frons commonly with a sharply defined granulate area 96 — Prothoracic precoxal piece moderately large, posteriorly angulate, oc- cupying anterior portion of area between coxae; male protibia armed by coarse marginal serrations and a row of equally coarse serrations on posteri- or face, female protibia with posterior face moderately inflated and armed by numerous, confused, small tubercles in addition to coarser marginal row; posterior face of female antennal club ornamented by more abundant, long hair; frons never ornamented by a sharply defined granulate area 97 96(95). Elytra broadly rounded behind, posterior margin of declivity feebly if at all explanate, weakly if at all divaricate; lateral margins of declivity armed by three pairs of spines; antennal club oval to subtriangular, little if any longer than wide; anteroventral (sternal) margin of prothorax flanged, bent or fold- ed posteriorly away from head, usually bearing a tuft of hair; pronotum usu- ally stouter, anterior margin usually serrate; antennal funicle 3-segmented .... Tricolus — Posterior margin of elytral declivity strongly to profoundly explanate, weak- ly to profoundly divaricate; declivital armature variable, antennal club oval to very elongate; anteroventral margin of prothorax fitting snuggly against head, sparsely pubescent; pronotum usually much more elongate, anterior margin variously sculptured, rarely serrate; antennal funicle usually 3-segmented, occasionally 2-segmented Amphicranus 97(95). Elytral apex divaricate, often also explanate; antennal club oval to broadly triangular; lateral margins of pronotum usually with a fine, raised line; body moderately to very slender Monarthrum — Elytral apex entire, never explanate; lateral margins of pronotum rounded; antennal club more than twice as long as wide (except 1.6 times in male Metacorthylu.s), its apex narrowly rounded; body comparatively stout 98 98(97). Antennal funicle 3-segmented; female frons excavated and elaborately orna- mented by long hair; antennal club not sexually dimorphic, elongate, slightly asymmetrical; pronotum and elytral disc glabrous Glochinocerus 76 Great Basin Naturalist Memoirs No. 6 Coptonotus 31. Scolytodes 32. ^ 33. Diamerus Camptocerus Fii;. 35. Posterior face of prothoracic tibiae: 25, Pwtuhijldste.s annosim, with tarsus (Platypodidae); 26, Pw- toplatijpus vettthts, with tarsus (Platypodidae); 27, Mecopelmtis zeteki, with first segment of tarsus (Platypodidae); 28, Schecllariiis mexicanus, with first segment of tarsus (Platypodidae); 29, Coptonotus cyclops, with first two tarsal seg- ments (Platypodidae); .30, Tricolus peltatus (Corthylini); 31, Scolytodes sp. (Ctenophorini); 32, Diamerus impar (Dia- merini); 33, Camptocerus auricomus (Scolytini). (After Wood 1973:86.) — Antennal funicle 2-seginented; frons convex and subglabrous in both sexes; antennal club asymmetrically very elongate in female, elongate-oval in male; pronotum and elytra minutely, closely pubescent Metacorthylns 99(94). Lateral margins of pronotum rounded; elytral disc usually impunctate, de- clivity .short, very steep, narrowly sulcate above, triangularly impressed be- low, costal margins near apex ascending slightly; antennal club subcircular, symmetrical, with two a.septate sutures marked by rows of .setae; female frons convex, pubescence inconspicuous Microcorthylus — Lateral margins of pronotum marked by a fine raised line (except some Cor- thycyclon), elytral disc usually with clearly marked, confused punctures, de- clivity convex, truncate, or variou.sly sculptured (but not as above); female frons usually moderately to strongly convex, often ornamented by hair; antennal club symmetrical to strongly asymmetrical, sutures present or not 100 100(99). Antennal club aseptate, without sutures (some species with weak transverse grooves, without rows of setae), usually very elongate; lateral margins of pronotum either with or without a fine, raised line; posterior face of protibia inflated and tuberculate; female frons broadly, evenly concave and ornamented by fine hair Corthycyclon 1982 Key to Genera 77 — Antennal club with one or two sutures, its outline subcircular to strongly asymmetrical (if sutures absent then posterior face of protibia flat, smooth); female frons variable 101 101(100). Elytral declivity narrowly, weakly sulcate (except convex in one species), lateral margins armed by two or three pairs of pointed granules; antennal scape elongate, clubshaped; female frons variously impressed, with a pair of median carinae narrowly separated by a sulcus over part or all of median line; color pale yellow to yellowish brown; antennal club symmetrical, broadly oval, with two finely marked sutures; protibia inflated, tuberculate .. Corthylocurus — Elytral declivity convex, truncately concave, or variously impressed (but never narrowly sulcate); antennal scape subquadrate, stout; female frons never with pair of median carinae; antennal club slightly to profoimdly asymmetrical, sutures (when present) rather strongly marked; posterior face of protibia smooth or tuberculate Corthylus Subfamily HYLESININAE Hylesinen Erichson, 1836, Archiv Naturgesch. 2:46 (Type-genus: Hylesinus Fabricius, 1801) Anatomical features.— The subfamily Hylesininae is distinguished from the Scoly- tinae by the separately arcuate basal margins of the elytra, with this basal margin slightly elevated and anned by a series of crenula- tions or in primitive tropical forms by a con- tinuous costa, by the rather broad, deep su- tural emargination, with the rounded or reduced scutellum slightly displaced posteri- orly. In addition the head is usually visible from above, the pronotum is either unarmed or with most asperities confined to the ante- rolateral areas (a few exceptions), the body form tends to be stouter, and the anterior coxae more commonly are separated. The an- terior tibiae are never as in Scolytus. A few South American species in one sec- tion of Cnetnonyx have basal crenulations on the elytra as well developed as in many Hy- lesininae. However, the character is not con- sistent nor present in all species of the group. The presence of this character in Cnemonyx indicates the primitiveness of the genus and suggests a possible point at which the two subfamilies might have diverged. The Hylesi- ninae apparently arose after the Platypo- didae had diverged from the main line of scolytid evolution and after the Scolytini had diversified, from a group perhaps not very unlike the more highly evolved Cnemonyx. The superficial resemblance of some genera, Hylastes and Hylurgops, to certain weevil genera can be attributed as much to evolu- tionary convergence to meet certain condi- tions in the environment as to genetics. Biological features.— Almost all North and Central American genera of Hylesininae are phloeophagus. The pith feeding Both- rosternini clearly were derived from phloeo- phagous types {Cnesinus annectens Wood), including the mycetophagous Bothrosternus. Dendrosinus, Phloeoborus, and two or three species of Chramesus are xylophagous. The primitive type of parental gallery in the Hy- lesininae was a transverse, biramous system as in Cnemonyx; longitudinal, pith, and radi- ate systems apparently were derived later as specializations appeared. All American spe- cies are monogamous except for the polyg- ynous Polygraphus and Carphoboriis, and for the apparent partial parthenogensis in some Bothrosternini. At least two tropical species of Phloeosinus (papuanus Schedl and a sim- ilar sympatric species) are also polygynous. Taxonomy.— A complete absence of agreement in published literature on the clas- sification of the Hylesininae led to a search for new characters that might make possible a more nearly phylogenetic classification of tribes and genera (Wood 1978). The (1) pres- ence or absence of an intersegmental suture between the scutellar area of the metanotum and its postnotum, (2) the course followed by the scutoscutellar suture on the metanotum, and (3) the structural arrangement of details in the locking mechanism at the base of the elytra were found to have significance in the characterization of tribes and in the grouping of genera. The result of these discoveries was a classification of this subfamily that is quite different from that seen in previous works (Wood 1978). The genera are now arranged in more meaningful groups that reflect true structural and, it is hoped, genetic relationships. 78 Tribe HYLASTINI Hylastes LeConte, 1876, Proc. Amer. Fhilos. Soc. 15:387 (Type-genus: llijlaates Erichson, 1836) Anatomical features.— The head is dis- tinctly subrostrate, scrobes are present, the frons is not sexually dimorphic, the eye is comparatively small and entire, the antennal funicle is 7-segmented, the antennal club is conical with distinct sutures, the basal crenu- lations on the elytra are poorly developed, the ridges extending from the anterior mar- gin of the coxae to the anterior margin of the prothorax are well developed, the tibiae are broadly expanded, and the tarsal segments are broad and pubescent. Biology.— All American Hylastini occur north from Honduras in coniferous hosts. They breed at or below the ground level in roots or in logs resting on the ground. The biramose adult tunnels are usually almost en- tirely in the phloem and evidently are not oriented with the grain of the wood. Larval mines wander irregularly in the phloem. Taxonomy.— Interstriae 10 extends to the declivity in Scierus and the front coxae are rather widely separated, suggesting that this genus is much more primitive than Hylastes or Hylurgops. The Hylastini are a rather highly specialized group of primitive Hylesininae. Genus SCIERUS LeConte Scierus LeConte, 1876, Proc. American Philos. Soc. 15:390 (Type-species: Scierus annectens LeConte, monobasic) Diagnosis.— This genus is very clo.sely al- lied to Hylurgops LeConte, with which some European writers placed it in synonymy; however, it is distinguished from that genus bv the much more widely separated anterior coxae, by the continuation of elytral inter- striae 10 to the level of abdominal sternum 5, by the complete absence of scalelike vesti- ture, and by the uniformly large pronotal punctures. Description.— Length 2.7-4.3 mm, 2.2 times as long as wide; secondary sexual dif- ferences obscure except for male stridulating device on abdominal tergum 7; head sub- rostrate, frons convex above, a pronounced transverse impression at level half way be- tween antennal bases and upper level of eyes, subinflated between impression and level of antennal insertion, flattened below; epistomal process not evident, premandibular epistomal lobe well developed. Eye elongate oval; en- tire. Antennal scape elongate, almost equal in length to 7-segmented funicle; club conical, with three distinct sutures. Pronotum nar- rower than elytra, narrowed and constricted anteriorly, unarmed, surface dull, with uni- formly large punctures. Scutellum small, oval, convex. Crenulations on elytral bases small, distinct; striae weakly impressed, punctures moderately large, deep; interstriae irregular dull, reticulate, obscurely punc- tured. Declivity convex, steep; more strongly sculptvired than on disc, interstriae tubercu- late. Vestiture consisting of sparse, yellow hair or bristlelike setae; never with scales on pronotum or elytra. Distribution.— New Mexico to British Columbia and eastward in the spruce forests to Quebec. Biology.— Usually found in the lower bole or roots of fallen trees or logs where tliey construct simple galleries in the cambium re- gion. The larvae feed primarily on the phloem tissues. Key to the Species of Scierus Pronotal surface granulo.se, setae not longer than diameter of a puncture; ely- tral interstriae irregular, subcrenulate to crenulate on middle half of disc, length of setae not equal to more than half width of an interstriae; declivital 79 80 Great Basin Naturalist Memoirs No. 6 tubercles larger and more abundant; Alaska, British Columbia, and New Mexico to Newfoundland; Picea, rarely in Pinus; 2.7-3.7 mm 1. annectens LeConte Pronotal surface reticulate, setae about twice as long as diameter of a punc- ture; elytral interstriae only slightly irregular, not at all, or minutely crenulate on middle half of disc, length of interstrial setae about equal to width of inter- striae; declivital tubercles small, not always easily seen; Alaska to Colorado; Abies lasiocarpa, Picea; 3.8-4.3 mm 2. pubescens Swaine 1. Scierus annectens LeConte Fisis. 36-37 Scierus annectens LeConte, 1876, Proc. Amer. Philos. Soc. 15:390 (Lectotype, sex?; Anticosta Island in Quebec; Mus. Coinp. Zool., present designation) Diagnosis.— Distinguished, often with some difficulty, from pubescens Swaine by characters summarized in the above key. Male.— Length 2.7-3.7 mm, 2.2 times as long as wide; color yellowish to reddish brown with yellowish pubescence. Frons convex above, transversely im- pressed at level half way between upper lev- el of eyes and level of antennal insertion, sub- inflated between this impression and level of Fig. 36. Scierus annectens. (After Bright 1976:205.) antennal insertion, flattened toward epis- toma; premandibular epistomal lobe rather large; surface granulose, punctures indistinct; vestiture rather abundant, coarse, very short and inconspicuous. Pronotum 0.83 times as long as wide; widest just behind middle, sides strongly ar- cuate on basal two-thirds, narrowed ante- riorly and distinctly constricted just before broadly rounded anterior margin; surface minutely granulose, punctures distinctly im- pressed on disc, rather large, close, of almost uniform size; vestiture short, coarse, usually not longer than distance equal to diameter of a puncture. Elytra L5 times as long as wide, 2.3 times as long as pronotum; sides almost straight and diverging very slightly on basal two-thirds to declivital base, somewhat narrowly rounded behind, posterior profile interrupted by de- clivital tubercles; crenulations on elytral bases small, distinct, not in a continuous row; striae distinctly impressed, punctures rather large, deep, poorly formed; interstriae about one and one-half times as wide as striae, ir- regularly convex, surface minutely granulate, obscure punctures confused, with their ante- rior margins elevated, mostly finely crenulate at least toward base and near declivity. De- clivity steep, convex; sculpture much as on disc except striae proportionately wider; in- terstriae 1 and 3 weakly elevated, 2 im- pressed and terminated below by a ridge ex- tending from junction of 3 and 9 to 1; interstrial crenulations more nearly tubercu- late, uniseriate, moderately large except on lower half of 2. Vestiture consisting of short, stout, recumbent interstrial setae; each seta about equal in length to diameter of strial pimcture. Female.— Virtually identical to male. Distribution.— Alaska and Arizona to Newfoundland and Maine. 1982 Hylastini 81 A A (SSSP^i^'^'"^^"' ^v-^r-y-w^il^W^f^^^^lwePi^fli^fi^MTy^tn*^^ H Fig. 37. Scierus annectens: A, entrance hole; B, tiirninif niche; C, larval mine; D, egg gallery, (.'\fter Stewart 1965:926.) ALASKA: Kenai. CANADA: Alberta: Banff, Jaspar Park, Lesser Slave Lake. British Columbia: Creighton Valley (Lumby), Glacier, Lorna, Pine Pass. New- foundland: Pasadena, Sandy Lake (Badger). Ontario: Frater. Quebec: Cascapiedia, Gaspe Peninsula (Burnt Jam Creek, St. John River), Laniel, Trinity Bay. USA: Arizona: Chiricahua Mountains, San Francisco Moun- tains. California: Big Bear Lake. Colorado: Boulder. Du- rango. Meeker, Montezuma N. F., New Castle. Idaho: Coeur d'Alene. Maine: Brunswick, Camp Caribou. Mon- tana; Glacier, Pray. New Hampshire: Crooks, W. Stuartstown. New Mexico: Sante Fe Sid Basin. Oregon: Ashland, Gold Lake (Willamette N. F.). Utah: .\shley N. F., Fish Lake N. F., La Sal Mountains, Logan Canyon, Wolf Creek Pass. Hosts.— Picea engelmannii, P. spp., rarely in Pinus contorta. Biology.— Stumps, the lower bole, and roots of rather large, prostrate trees, or the lower side of logs are usually selected for at- tack. The adult galleries are in the cambium region mostly in the phloem and are of a simple monoramous type. The larvae feed primarily upon phloem tissues. Notes.— The above treatment was based upon 352 specimens. Variation in the series examined appeared to be as great between individuals as between series from different areas. The first specimen in LeConte's syntypic series, cited above, has been re- garded as the type and is here designated as the lectotype of annectens. The fourth and last specimen in his series (Vancouver) is of Aniphagus aspericollis. 2. Scierus pubescens Swaine Scierus pubescens Swaine, 1924, Canadian Ent. 56:287 (Holotvpe, female; Jasper Park, .-Mberta: Cana- dian Nat., Coll., 728) Diagnosis.— In addition to characters mentioned in the above key, this species is distinguished by the larger punctures on the pronotum and the elytral striae, by the finer, longer vestiture, by the finer sculpture, and by the more nearly shining, reticulate surfaces. Male.— Length 3.8-4.3 mm, 2.26 times as long as wide; color reddish brown, with pale yellow vestiture. Frons as in annectens but surfaces less granulose, vestiture slightly longer; frontal area somewhat more slender, transverse im- pression evidently deeper. Pronotum 0.96 times as long as wide; as in annectens except sides much less strongly 82 Great Basin Naturalist Memoirs No. 6 arcuate, surface reticulate, not at all granu- late, punctures larger, more sharply im- pressed, and vestiture finer, distinctly longer. Elytra 1.7 times as long as wide; as in an- nectens except posterior profile more finely serrate, interstriae proportionately narrower, about as wide as striae, anterior margins of interstrial punctures much more finely crenu- late, general surface coarsely reticulate, de- clivital interstriae less strongly convex, 2 much less strongly impressed, with all tu- bercles much smaller, and vestiture longer, each seta up to twice as long as width of a strial puncture. Female.— Sexual differences not readily apparent except those involving abdominal terga. Distribution.— Alaska to Colorado. ALASKA: Kenai Peninsula. 8-VI-74, trap, M. M. Fur- niss. CANADA: Alberta: Jasper Park, VIII- 15, no. 2232a, Picea, J. M. Swaine. British Columbia: Haines Road, 10- VIII-52; London Hill Mine, Bear Lake, 7000 ft, on snow; Lorna, 22-VI-25, no. 163 lot .3807, Abies lasiocarpa. USA: Colorado: Argentine Road, 1938, Wickham; New Castle, VII-VIII. Hopk. US 31408B, Picea engelmannii. C. L. Massey. Idaho: McCall, 23-VI to 12-VIII-72 Hopk. 58402, D. R.' Oakes. Hosts.— Abies lasiocarpa, Picea engelniannii. Biology.— Presumably similar to annectens. Notes.— The above treatment was ba.sed on the holotype and on 81 other specimens. Genus HYLURGOPS LeConte Hylurgops LeConte, 1876, Proc. American Philos. Soc. 15:389 (Type-species: Hylastes pinifex Fitch, sub- sequent designation hv Hopkins, 1914, Proc. U.S. Nat. Mu.s. 48:123) Diagnosis.— Within the tribe Hylastini this genus is very closely related to Hylastes, from which some species are distinguished with difficulty. In addition to characters mentioned in the above key, Hylurgops spe- cies normally have rows of fine, long, hair- like, interstrial setae on the declivity (sometimes abraded); hairlike setae in Hy- lastes, if present, are not longer than the ground vestiture. Description.— Length 3.1-5.7 mm, 2.4-2.8 times as long as wide; secondary sex- ual characters clearly evident only on ab- dominal terga. Frons with a transverse impre.ssion midway between level of antennal insertion and up- per level of eyes, convex above, flattened to weakly convex below this point; lower area usually with a median carina. Eye subovate, entire. Antennal fimicle 7-segmented; club conical, basal segment much longer than others, at least two sutures indicated. Pro- notum usually strongly constricted just be- hind anterior margin, surface unarmed, punc- tured. Scutellum small, oval. Crenulations on elytral bases poorly developed, bases usually not elevated; striae impressed or not, punc- tures distinct; interstriae variously sculp- tured. Declivity convex, steep. Vestiture in- cluding both hairlike and scalelike setae. Distribution.— The Holarctic realm; sev- en species including two with subspecies oc- cur throughout the coniferous forests of North and Central America south to Guate- mala (and probably Honduras) wherever rep- resentatives of the Pinaceae are native. Thir- teen additional species occur in the Palaearctic realm. Biology.— All species construct hylesinine simple or biramous egg tunnels in phloem tis- sues and may engrave the wood slightly. Eggs are placed in niches and are packed in frass. The larvae mine phloem tissues in an aimless pattern; the larval tunnel usually is visible on the inner surface of peeled bark. The stump and roots are .selected for attack by some spe- cies, others attack the bole or even limbs of fallen trees or they may invade logs. Some species breed primarily in injured or weak- ened green bark, others prefer logs with sour- ing bark. Key to the Species of Hylurgops Declivital interstriae equally convex, their tubercles .small; pronotal vestiture hairlike; crenulations on basal margins of elytra rather poorly developed Alternate declivital interstriae strongly elevated and armed by rather large tu- bercles; pronotal ground vestiture consisting of abundant, small scales, .some hairlike setae usually intermixed; crenulations on elytral bases rather well developed 1982 Hylastini 83 2(1). Posterior half of lateral margins on pronotum acutely elevated; lateral margins of pronotum straight on more than basal half, very feebly convergent; pronotal vestiture erect, rather abundant, long, many setae at least equal in length to those on declivity; longest declivital setae abundant, confused, not in rows; Arizona, New Mexico to Guatemala; 4.6-5.7 mm 1. incomptus (Blandford) — Lateral margins of pronotum transversely rounded, moderately to strongly ar- cuate in outline from base to constriction on anterior fourth; pronotal vestiture recumbent, very short or absent; longest hairlike setae on elytral declivity in sparse, uniseriate rows 3 3(2). Body more slender, at least 2.5 times as long as wide; pronotum longer than wide; normal body color black; basal angles of pronotum rather abruptly roimded; transverse constriction on pronotum obscure 4 — Body stouter, less than 2.3 times as long as wide; pronotum wider than long; normal body color dark reddish brown; basal angles of pronotum rather broadly rounded; pronotum with a distinct transverse constriction on anterior fourth 7 4(3). Small and large pronotal punctures only slightly different in size, most inter- spaces less than half as wide as diameter of a puncture; body stouter, 2.6 times as long as wide; Arizona and New Mexico to Honduras; 3.8-5.3 mm 2. planirostris (Chapuis) — Largest punctures on pronotal disc about twice as large as smallest, most inter- spaces between punctures at least equal in width to smallest punctures; body more slender, 2.7 times as long as wide 5 5(4). Hairlike setae on pronotum and elytra very fine and exceedingly long, at least twice as long as distance between interstrial rows of long hair on elytra; high altitudes of Puebla and Mexico; 3.8-4.6 mm 4. longipennis (Blandford) — Hairlike setae on pronotum and elytra shorter, length not exceeding distance between rows of interstrial hair 6 6(5). Elytral surface smooth, shining; submarginal crenulations at base of elytra acute, marginal crenulations rather well developed; median frontal carina acutely elevated, extending a short distance above transverse impression near epistoma; pronotal punctures usually much coarser, deeper; British Columbia and Alberta to California and New Mexico; 3.3-4.6 mm 3. porosus (LeConte) — Elytral surface minutely reticulate; elytral bases without acute crenulations, marginal crenulations rather poorly developed; frontal carina indistinct, visible only in transverse impression immediately above epistoma; pronotal punctures smaller, closer, usually not as deep; Northwest Territories to California and New Mexico; 3.7-5.0 mm 5. reticulatus Wood 7(3). Scalehke elytral vestiture confined to declivity; elytral disc with only a few crenulations in uniseriate rows, these usually narrow and more nearly tubercu- late, most interstrial punctures on middle half almost normal (not crenulate); setae on lateral and basal margins of pronotum very fine; pronotum reticulate; California to Coastal British Columbia and Alaska; 3.6-4.8 mm 6. rugipennis rugipennis (Mannerheim) — Scalelike vestiture extending anteriorly to middle of elytral disc; elytral disc with most interstrial punctures crenulate or subcrenulate, confused; setae on lateral and basal margins of pronotum coarse; pronotum smooth, shining (inter- mediate in zone of intergradation); Utah and Colorado to inland British Co- lumbia and east through the coniferous forest to Nova Scotia and Alabama; 3.7-5.2 mm 7. rugipennis pinifex (Fitch) 84 8(1). Great Basin Naturalist Memoirs No. 6 Odd-numbered declivital interstriae rather strongly, more uniformly elevated and anned by moderately large tubercles; strial punctures smaller, interstrial bristles finger; N Arizona and N New Mexico to Alaska; 3.1-4.2 mm 8. subcostulatus subcostulatus (Mannerheim) Odd-numbered declivital interstriae very strongly elevated, conspicuously con- stricted laterally and in height between much coarser tubercles; strial punc- tures distinctly larger, interstrial bristles coarser; S Arizona and S New Mexico to Honduras; 3.3-4.4 mm 9. subcostulatus alternans (Chapuis) 1. Hylurgops incomptus (Blandford) Hylastes incomptus Blandford, 1897, Biol. Centr. Amer., Coleopt. 4(6): 14.5 (Syntypes; .\ndres Chalchico- mula, now Ciudad Serdan, Piiebla, Mexico; Brit- ish Mus. Nat. Hist) Hylurgops grandicoUis Swaine, 1917, Dom. Canada Dept Agric. Ent. Br. Bnll. 14:17 (Lectotype, sex?; Cloiidcroft, New Mexico; Canadian Nat. Coll, designated by Bright, 1967, Canadian Ent. 99:67.5); Wood, 1957, Canadian Ent. 89:.397. ^ijnomjmij Diagnosis.— In addition to characters mentioned in the above key this species is distinguished by the deeply impressed centers of the pronotal punctures. Female.— Length 4.6-5.9 mm, 2.6 times as long as wide; color black. Frons with a moderately strong, transverse impression near middle about midway be- tween upper level of eyes and level of anten- nal insertion, rather strongly convex above and weakly convex below except weakly im- pressed laterally just above epistomal margin; epistomal lobe broad, not very strongly pro- duced; surface smooth and shining, with close, deep, rather coarse punctures; vestiture consisting of fine, long and short, rather sparse, hairlike setae. Pronotum 1.1 times as long as wide; widest at base, sides very weakly arcuate and feebly converging on basal two-thirds, rather broad- ly rounded in front; lateral margins sharply, subacutely elevated on at least basal half; sur- face smooth and shining, with abundant, close, deep, medium and small punctures ex- cept on median line; an elevated median line vi.sible on about three-fourths of pronotum length; vestiture consisting of rather abun- dant, erect, hairlike setae of variable length, many of them about as long as those on ely- tral declivity. Elytra 1.7 times as long as wide, 1.8 times as long as pronotum; sides straight and paral- lel on basal two-thirds to declivital base, then rather broadly rounded behind; .striae not at all impressed, punctures small, rather deep, obscure; interstriae at least twice as wide as striae, shining, interrupted by numerous deeply impressed, irregular, transverse lines, tubercles or crenulate elevations entirely ab- sent. Declivity steep, convex; striae weakly impressed, punctures more nearly evident; interstriae 1 and 3 weakly, 9 moderately ele- vated, each bearing a row of fine granules; interstriae with moderately abundant, fine punctures. Vestiture consisting of short, rather sparse scales, and fine, long, rather abundant confused, hairlike setae on declivity and sides. Male.— Evidently identical to female ex- cept on abdominal terga. Distribution.— Arizona and New Mexico to Guatemala. USA: Arizona: Chiricahua Mts., Flagstaff, Huachuca Mts., Oak Creek Canyon, Paradise, Santa Catalina Mts., Williams. New Mexico: Beulah, Capitan Mts., Cloud- croft, Coolidge, Las Vegas, Lincoln N. F., Peloncillo N. F., Santa Fe Canyon, White Mts. MEXICO: Chiapas: Mesa del Huracan, 24-VII-64, Pinus engehnannii. J. B. Thomas; San Cristobal, 8-VII-69. Distrito Federal: 24 km S El Guarda, 14-XI-46. Durango: 60 km, SW El Sal- to, 2.3-VII-5.3 Pinus, S. L. Wood. Hidalgo: 7 km E Za- catlan, 12-VI-67, 2900 m. No. 20, Pinus, S. L. Wood. Mexico: 70 km W Toliica, 1.5-VII-53, Pinus. S. L. Wood; Tlalmonalco, P. leiophijUa, P. J. Perrv. Puebia: 8 km SW Teziiitlan, 18-VII1-58, Pini«, H. F. Howden. Tlaxcala: 20 km N Tlaxco, 9-Vn-67, Pinus, No. 181, S. L. Wood. Veracruz: 5 km E Perote, 15-Vl-,53, 2400 m, Pinus, S. L. Wood; Las Vigas, 18-XII-48, H. B. Leech. GUATE- MALA: Cerro Calel, Quezaltenango, 26-V-64, 3100 m. No. 620, Pinus pseuclostrobus, S. L. Wood; San Cristo- bal, Huehiietenango, 28-V-64, 2300 m, Pinus pseudo- stwhus. S. L. Wood; Tecpam, 11-X-.32, 600 m, Pinus. Hosts.— Probably any species of Pinus within the distribution. Biology.— This species breeds in stumps of dead or dying pines near or below ground level. Egg galleries are constructed primarily in the phloem ti.ssues and lightly score or at least stain the surface of the wood. The ir- regular larval mines wander through the 1982 Hylastini 85 phloem tissues and are usually visible on the inner surface of the bark through at least part of their length. Notes.— The types of both incomptus and grandicollis were examined. The above treat- ment was based on my female homotype of incomptus from Cerro Calel and on 151 addi- tional specimens. 2. Hylurgops planirostris (Chapuis) Fig. 41 Hylastes planirostris Chapuis, 1869, Synopsis des Scoly- tides, p. 21 (Lectotype, female; Suapan, Mexico; Mus. d'Hist. Nat., Brussels, subsequent designa- tion by Wood, 1971, Great Basin Nat. 31:146) Hylurgops knausi Swaine, 1917, Dom. Canada Dept. .\gric. Ent. Br. Jech. Bull. 14(1): 17 (Lectotype, sex?; Cloudcroft, New Mexico; Canadian Nat. Coll., subsequent designation by Bright, 1967, Canadian Ent. 99:675); Wood, 1971, Great Basin Nat. 31:146. Synonymy Diagnosis.— This species is closely related to porosus, but it may be distinguished by characters summarized in the above key. Male.— Length 3.8-5.3 mm, 2.6 times as long as wide; color black. Frons as in incomptus, but perhaps more coarsely punctured; median carina variable. Vestiture short. Pronotum 0.9 times as long as wide (rarely 1.0); widest near middle, sides rather strongly arcuate from base to feeble constriction just before rather broadly rounded anterior mar- gin; surface shining, densely punctured by rather deep punctures of almost uniform size, interspaces almost never as wide as diameter of a small puncture; glabrous except for a few setae on lateral margins. Elytra 1.7 times as long as wide; as in po- rosus except striae tending to be less deeply impressed, punctures narrower, and inter- striae perhaps less irregular and wider. Female.— Differences not apparent except on abdominal terga. Distribution.— Arizona and New Mexico to Honduras. USA: Arizona: Alpine, Chiricahua Mts., Flagstaff, Globe, Graham Mts., Hanagan Camp (Greenlee Co.), Paradise, Patagonia, Pinaleno Mts., Santa Catalina Mts., WTiite Mts. New Mexico: Alto, Buelah, Capitan, Cloud- croft, Las Vegas, Lincoln N. F., Magdalena (Socorro Co.), Pecos N. F., Sacramento Mts., Silver City. ME.Xl- CO: Chiapas: El Bosque; 8 km S San Carlos, 6-1II-63, H. C. Bechtel; 8 km E San Cristobal, 8-V1I-69, Pinus ayacii- hiute, D. E. Bright. Chihuahua: Creel, 18-VlI-6(), and La Laja, 16-Vll-60^ S. L. Wood. Distrito Federal: Mexico. Durango: 16 km W El Salto, VII-64, J. B. Thomas. Hi- dalgo: 6 km E Zacatlan, 12-VI-67, S. L. Wood. Mexico: 70 km W Toluca, 15-VII-53, S. L. Wood. Michoacan: 55 km E Morelia, 14-V1-65, Pinus, S. L. Wood. Tlaxcala: 17 km N TIaxco, 9-VII-67, Pinus, S. L. Wood. Veracruz: 26 km NW Jalapa, 29-VI-53, Pinus S. L. Wood; 11 km SE Las Vigas, 18-XII-48, H. B. Leech. GU.\TEMALA; Cer- ro Calel, 26-V-64, P. pseudostrohus, S. L. Wood; Tecpan, 24-1 V-56, Pinus, R. L. Furniss; Totonicipan. Hosts.— Evidently all species of Pinus within its range. Biology.— This species tends to infest logs or the bole of fallen trees and, when abun- dant, may completely replace Ips in a given log. The tunnels appear to be similar to those of incomptus. Notes.— The above treatment is based on the lectotypes of planirostris and knausi and on 481 other specimens. One specimen in a long series of this spe- cies, from Cloudcroft, New Mexico, and a unique specimen from the Chiricahua Moun- tains, Arizona, exhibit characters almost exactly intermediate between this species and porosus. Several specimens of both species from central Arizona and New Mexico sug- gest slight intergradation of characters be- tween these two species. While the two in- termediate specimens suggest hybridization or intergradation of species, the material presently at hand does not warrant reducing them to subspecies of one another. 3. Hylurgops porosus (LeConte) Figs. 38, 41 Hylastes porosus LeConte, 1868, Trans. .American Ent. Soc. 2:175 (Lectotype. female?; California; Mus. Comp. Zool., designated by Wood, 1971, Great Basin Nat. 31: 147) Hylurgops lecontei Swaine, 1917, Dom. Canada Dept. .\gric. Ent. Br. Tech. Bull. 14(1):16 (Holotvpe, sex?; Colorado; Canadian Nat. Coll., 9242); Wood, 1971, Great Basin Nat. 31:147. Synonymy Diagnosis.— This variable species is close- ly allied to planirostrus (Chapuis) and occa- sional specimens from the zone of over- lapping distributions can be distinguished only by the relative size and density of pro- notal punctures. Female.— Length 3.6-5.3 mm, 2.7 times as long as wide; color black. Frons as in incomptus but perhaps more coarsely punctured; a median carina on 86 Great Basin Naturalist Memoirs No. 6 lower third sometimes more definite. Vesti- ture short. Pronotum 1.1 times as long as wide (rarely to 1.0); sides usually widest one-third from base, moderately arcuate to a feeble con- striction just before broadly rounded anterior margin, some specimens with sides on basal half almost straight and parallel; surface shin- ing, with large and small punctures inter- mixed in variable proportions (most com- monly in about equal numbers), largest punctures about twice as large as smallest, some of interspaces on disc at least equal in width to diameter of a small puncture; me- dian line usually visible on middle third; glabrous except at margins, setae short. Elytra 1.8 times as long as wide, 1.9 times as long as pronotum; profile as in incomptus; striae usually slightly impressed toward de- clivity, punctures large, deep; interstriae slightly narrower than striae, punctures small, abundant, confused, surface usually Fig. 38. Htjlurgpps porosus: Outline from dorsal aspect, with sculpture of pronotum indicated. Fig. 39. Hijlurgops rugipennis piriifex: Outline from dorsal aspect, with sculpture of pronotum indicated. Fig. 40. Hylurgops subcostulatiis subspecies: A, s. suhcostulatus, outline from dorsal aspect; B, same, declivity; C, s. alternans, declivity. 1982 Hylastini 87 shining, slightly irregular especially toward declivity. Declivity steep convex; striae and interstriae somewhat narrower; interstriae 1 (usually) and 9 weakly elevated; all inter- striae with a row of uniseriate, widely spaced, fine granules. Vestiture consisting of small, moderately abundant scales on declivi- ty and asually on posterior area of disc, and uniseriate rows of long, fine, erect, interstrial hair on declivity, usually abraded on disc, each seta about as long as distance between rows or less, spaced within a row by about once or twice this distance. Male.— Evidently identical to female ex- cept on abdominal terga. Distribution.— British Columbia and Sas- katchewan to Arizona and New Mexico. CANADA: Alberta: Banff, Cypress Hills, Laggen, Lake Louise. British Columbia: Ashcroft, Aspen Grove, Atlin, Chilcotin, Cranberry Brook, Kingsvale, Lac Le Jeune, Loma, Midday Valley, Sidney, Summerland, Tre- pan Creek, Trinity Valley, Vancouver, Vermillion Sum- mit, Vernon, Yoho Park. Saskatchewan: Cypress Hills. USA: Arizona: Flagstaff, Kaibab N. F., Prescott, Califor- nia: Berkeley, Bumey, Chester, Inverness, Lassen N. F., Northfork, Norval Flats, Oakland, Orinda, Pinecrest, Placerville, Plantation (Sonoma Co.), San Francisco, Sequoia N. P., Silver Lake, Summit Lake (Shasta Co.), Truckee, Tulare Co., Yosemite. Colorado: Bvers R. S., Colorado N. F., Estes Park, Evergreen, Ft. Collins, Ft. Fig. 4L Hylurgops spp., distribution map; porosus, .solid circles; planirostris, open circles. Garland, Glenhaven, Leadville, Pingree Park, San Juan N. F., Tercio, Uncompahgre N. F., Whitman. Idaho: Centerville, Ellis, McCall, Moscow, Salmon, .Sandpoint, Winchester. Montana: Cabinet N. F., Columbia Falls, Flathead Lake, Helena, Niger Hill (Powell Co.), Rockv Boy Indian Reservation (Hill Co.), Seeky Lake. Nevada: Minden in Douglas Co. New Mexico: Hermit Peak near Sante Fe. Oregon: Beatty, Bly, Corvalli.s, Crater Lake, Gold Lake (Willamette N. F.), Grant Co., Klamath Falls, McMinnville, Medford, Pineville, Rankin, Santiam Pass. South Dakota: Black Hills, Custer, Pine Ridge. Utah: Beaver, Elk Park (Ashley N. F.), Kamas, Logan Canyon, Long Hollow (Dixie N. F.), Panguitch, Soap- stone (Uinta N. F.), Wolf Creek Pass. Washington: Buckeye, Cheney, Chewelah, Glenswood, Kooskookie, Thorton. Wyoming: Afton, Mountain View, Saratoga, Yellowstone N. P. Hosts.— Pinus attenuata, P. contorta, P. flexilis, P. jeffreyi, P. ponderosa, P. radiata, less common in Picea. Biology.— Essentially as in incomptus. Notes.— This abundant and variable spe- cies is probably misidentified more com- monly than any other North American scoly- tid. Within a series from any given locality the pronotal punctures and the impression of the elytral striae may vary considerably, but, contrary to Swaine's (1918:82) note, I fail to associate this variation with geography. The above treatment was based on the lec- totype of porosus, on the holotype of lecontei, and on more than 2000 other specimens. See the note above under planirostris concerning possible intergradation between these species. 4. Hylurgops longipennis (Blandford) Hylastes longipennis Blandford, 1896. Biol. Centr. Amer., Coleopt. 4(6): 143 (Lectotype, female; Rancho de Popocatepetl, Mexico; Briti.sh Mus. Nat. Hist., present designation) Diagnosis.— This species is distinguished from porosus (LeConte) by the slightly small- er average size, by the more slender body form, by the more finely punctured frons, by the much steeper elytral declivity, and by the different declivital vestiture as described below. Female.— Length 3.8-4.6 mm, 2.8 times as long as wide; color black. Frons as in porosus except punctures aver- aging slightly smaller, median carina usually indicated but less well developed. Pronotum as in porosus, punctures aver- aging slightly smaller. Great Basin Naturalist Memoirs No. 6 Elytra 2.1 times as long as wide, 2.3 times as long as pronotum; similar to porosus ex- cept strial punctures slightly smaller, deeper, interstrial punctures slightly smaller, not at all subcrenulate, declivity much steeper, par- ticularly on lower half, scales confined to de- clivity, much less abundant (concealing less than one-third of surface area, interstrial setae very fine, in rows, each seta one to three times as long as distance between rows, spaced within a row by about half distance between rows. Male.— Similar to female except median frontal carina less distinct. Distribution.— Mexico. .MEXICO: Mexico: Rancho de Popocatepetl, h(eight)t 3800 met(res), Septr., E. Triiqui; Popocatepetl, VII-VIII-78, pheromone trap, Hopk. 61847, M. M. Fur- niss; 11 miles (17 km) E Amecameca, 31-V-74, 3200, C. VV. and L. O'Brien; Parqiie Zoquiapan, 15-XII-79, T. H. Atkinson. Notes.— Blandford named longipennis from a syntypic series of five specimens la- beled "Tmqui, Mexico" from the Frey col- lection. One of the specimens bears the num- ber 23337 and, according to Dr. R. T. Thompson, is listed in the Frey collection register with the note "Rancho de Popocate- petl, h(eight)t 3800 met(res) Septr."; it was collected by Eugen Truqui some time prior to 1860. Included in the entry is "Tomolips asperatus Woll(aston) Type." Since Tomolips bicalcaratus Wollaston { = asperatus Wollas- ton) (family Curculionidae) is a relatively common species in the stumps and roots of Pinus leiophylla, and perhaps other pines in the Estado de Mexico, it is assumed that long- ipennis occurs in this habitat. Since a type has not been selected from Blandford's syntypic series, I here designate the second specimen in the series, a female, as the lectotype for Hijlastes longipennis Blandford. In addition to the five syntypes, 10 specimens were examined. 5. Hyhirgops reticulatus Wood Hylurgops reticulatus Wood, 1971, Great Basin Nat. 31:71 (Holotype, male; Summit Lake, Shasta Co., California; Wood Coll.) Dia(;nosis.— This species is distinguished from porosus (LeConte) by the larger average size, by the minutely reticulate elytra, and by other characters included in the above key. Male.— Length 3.7-5.0 mm, 2.8 times as long as wide; color black, with whitish vestiture. Frons as in porosus except lower half less deeply, less closely, less finely punctured; median carina almost obsolete, visible only in impression immediately above epistoma. Pronotum as in porosus except usually widest near middle, converging anteriorly more abruptly; surface often partly or entire- ly reticulate, punctures about as on some po- rosus but finer than on most; largest punc- tures about twice as large as smallest, spaced by distances equal to or smaller than diame- ter of smallest punctures. Elytra as in porosus except basal crenula- tions more poorly developed, submarginal crenulations absent; entire surface minutely reticulate (visible at 80 diameters magnifica- tion, not at 40 diameters); interstrial punc- tures smaller, more numerous; interstriae very slightly wider, surface less irregular; in- terstrial crenulations near declivity narrower, very slightly higher; declivital scales more abundant, extending to or slightly anterior to base of declivity; setae in interstrial rows very slightly longer, distinctly coarser. Last visible abdominal sternum never grooved or pubescent as in males of most other Hylurgops species. Female.— Similar to male except anterior tibiae with five (male with six) socketed teeth; terminal, concealed segments of abdo- men only reliable indicator of sex, as in many other species of this subfamily. Distribution.— Northwest Territories and Montana to California and New Mexico. C'ANADA: British Columbia: Aspen Grove, Indian Meadows, Lake Cowichan, Merritt (Midday Valley), Pender Harbor, Princeton, Robson, Spioiis Creek, Sum- merland. Trinity Valley, Vancouver, Voght Valley. Northwest Territories: Norman Wells. US.\: .\rizona: Chiricahna Mts., Coconino N. F., Flagstaff, Jerome, Williams. California: Anderson Valley. Baldwin Lake, Big Bear Lake, Big Pines (Los Angeles Co.), Burney, Carmel, Camp Greeley, Carrville (Trinity Co.), Coffee Creek (Trinity Co.), Del Monte, Facht (Lassen Co.), Hayfork (Trinity Co.), Horse Creek, Huckleberry Mead- ows (Freeman Co.), Lassen N. F., Mammoth, Manzanita Lake (Lassen Co.), Miami R. S. (Mariposa Co.), Mon- terey, Norval Flats (Lassen Co.), Pacific Grove, Pine- crest, Redstone Station (Tulare Co.), Salt R. S. (Glen Co.), Stevenson Creek (Fresno Co.), Summit Lake (Shasta Co.), Summerdale, Ventura, Willow Ranch, 1982 Hylastini 89 Yoseniite N. P. Colorado: Badger, Boulder, Ft. (Jollins, Glenhaven, Woodland Park. Idaho: Centerville, Idaho City, Moscow, Priest River, Smith's Fcrrv, Winchester. Montana: Columbia Falls, Cramer Creek, Darby, Helena, Kalispell. Nevada: Galena Creek (Washow Co.), Kyle Canyon (Clark Co.). New Mexico: Capitan, Cloud- croft, Lincoln N. F., Meek. Oregon: Ashland, Cedar Mt., Grants Pass, Hood River, Klamath Falls, Prineville, Wal- lowa N. F. South Dakota: Pine Ridge. Utah: Eureka, Mammoth Mt. Wa.shington: Buckeve, Olvmpic N. P., Pullman, Quinault, Sunrise Park, Taeoma, Toppenish. Hosts.— Pinus jeffreyi, P. ponderosa, P. radiata, P. spp. Biology.— Evidently very similar to porosus. Notes.— The above treatment was based on the type series of 86 specimens and on 87 other specimens. 6. Hylurgops rugipennis rugipennis (Mannerheim) Fig. 42 Hylastes rugipennis Mannerheim, 1843, Moskov. Obshch. Isp. Prirody, Otd. Biol. Biul. (Bull. Soc. Imp. Nat. Moscou) i6(2):297 (Syntypes?; Sitka Is- land, Alaska: lost? Not in Helsinki Mus.) Diagnosis.— This form intergrades on a narrovi^ zone with r. pinifex (Fitch), from which it may be distinguished by characters simnmarized in the above key. Male.— Length 3.6-4.8 mm, 2.44 times as long as wide; color reddish brown. Frons essentially as in incomptus but with the median carina acute. Pronotum about 0.9 times as long as wide; widest about a third pronotum length from base, sides strongly arcuate and converging to constriction just behind broadly rounded an- terior margin; surface shining, closely, rather deeply, almost uniformly punctured; vesti- ture very fine, hairlike, usually abraded. Elytra 1.7 times as long as wide, 2.1 times as long as pronotum; sides almost straight and parallel on basal two-thirds to declivital base, then broadly rounded behind; striae slightly impressed, punctures rather small, deep; in- terstriae as wide as striae, convex, slightly ir- regular, punctures fine, confused, a few of them narrowly crenulate, tending to form an indefinite row of tubercles. Declivity steep, convex; striae more narrowly impressed than on disc; interstriae 1 and 9 weakly elevated, 2 feebly impressed; each armed by a row of fine, rather widely spaced granules. Vestiture consisting of short ground cover of broad. oval scales on declivity, replaced by fine hair on upper declivity and disc (scales very rarely extend anterior to declivital base), and rows of longer, erect, interstrial hairlike bristles. Female.— Evidently as in male except on abdominal terga. Distribution.— The Pacific Coast from Alaska to California. AL.ASK,^: Farragiit Bay, Ft. Yukon, Juneau, Ketchi- kan, Kodiak Island, Loring, Sitka, Skagway. CAN.\DA: British Columbia: Aspen Grove, Beaton River, Creston, Glacier, Inverness, Lorna, Mainland, Massett (Queen Charlotte Islands), McBride, Merritt (Midday Valley), Mutokatla, Pine Pass, Skidgate, Stanley Park, Tavlor Lake, Terrace, Trinity Valley, Vancouver. Yukon: Yukon Terr. USA: California: Carmel, Crescent City, Del Norte, Inverness, McKerrick (Mendocino Co.), Mon- terey, Pacific Grove. Oregon: Ahlers, .\storia, Breiten- bush, Cannon Beach, Crater Lake, Detroit, Fogarty, Gold Lake (Willamette N. F.), McMinnville, Newport, North Bend, Otis, Portland, Santiam Pass, Seaside, Taft, Waldport. Washington: Aberdeen, Easton, Eatonville, Forks, Friday Harbor, Hoqiiiam, Lake Crescent, Metal- ine Falls, Mt. Adams, Mt. Rainier, Olympic N. P., Quinault, Satsop, Sauk, Sulton. Hosts.— Picea engelmannii, P. sitchensis, Pinus attenuata, P. contorta, P. monticola, P. muricata, P. radiata, and Pseudotsuga menziesii. Biology.— Specimens in humid areas along the Pacific Coast were taken either from limbs or the bole of fallen trees. The bi- ramous, transverse egg tunnels are of the characteristic hylesinine type that are pri- marily in the phloem tissues but may engrave the wood slightly. Larval mines wander aim- lessly in the phloem tissues and usually are at least partly visible on the inner surface of peeled bark. Notes.— The above treatment was based on two specimens from Juneau, Alaska, and on 75 other specimens from localities listed above. Specimens from the coastal areas appear to be anatomically and biologically distinct from those east of the area from the Cascade Mountains to Vernon, British Columbia. Near this line series may fit one form or the other, they may be intermediate in the characters exhibited, or they may contain a mixture of extremes and intermediates of both forms. The zone of intergradation appears to be rel- atively narrow and except near this line the coastal form represented bv the name rugi- pennis, is easily distinguished from the more 90 Great Basin Naturalist Memoirs No. 6 widely distributed inland or eastern form represented by the name pinifex. In view of this narrow zone of intergradation between two otherwise distinct populations, sub- species must be recognized. 7. Hylurgops rugipennis pinifex (Fitch) Figs. 39, 42 Hyhstes pinifex Fitch, 1858, Trans. New York Agric. Soc. 17:729 (Lectotype, female; New York; U.S. Nat. Mus., 42807, present designation) Diagnosis.— As mentioned above under r. rugipennis, there appears to be inter- gradation between these forms. Therefore, they are treated as subspecies that can be separated from one another by characters mentioned in the above key. Male.— Length 3.7-5.2 mm, 2.48 times as long as wide; color reddish brown. Frons as in r. rugipennis. Pronotum as in r. rugipennis except more small punctures usu- ally present. Elytra 1.5 times as long as wide, 1.8 times as long as pronotum; profile as in r. rugi- pennis; striae slightly impressed, punctures rather small, deep; interstriae as wide as striae, slightly convex, shining, most punc- tures weakly to moderately crenulate, many crenulations half as wide as interstriae and not oriented to form a uniseriate row. Decliv- ity as in r. rugipennis. Vestiture consisting of short, oval scales on entire declivity, often ex- tending to anterior half of disc, u.sually re- placed anteriorly by hairlike setae; and rows of bristles as in r. rugipennis. Fig. 42. Hylurgops ruffpenni.s- subspp.. distrihiition map: r. rujripennis. open squares; r. pinifex, solid squares. 1982 Hylastini 91 Female.— Evidently similar to male ex- cept on abdominal terga. Distribution.— Inland British Columbia to Utah and Colorado then eastward to Nova Scotia and Alabama. CANADA: Alberta: Cypress Hills, Jasper, Loggan, Waterton N. P. British Columbia: Aspen Grove, Lorna, Marysville, Rolla. Manitoba: Grass River. New Bruns- wick: Bathurst, Fredricton, McGraw Brook, Plaster Rock, St. Louis, Salmon River. Nova Scotia; Kejimkuyik. Ontario: Algongiiin Park, Chalk River, Constance Bay, Ft. Williams, Longlac, Marmora, Petawawa, Quetico Park, Seaforth (Lake Huron), The.ssalon, Toronto, Whi- tefish Point. Quebec: Aylmer, Ft. Coulonge, Hudson, Hull, Lake Memphremagog, Lake Opasatika, Laniel, Ri- gaud, Quebec, St. .\nne de Bellevue. US.'\; Alabama: Mobile. Arizona: Williams. California: Blancos Corral in White Mts. (Mono Co.). Colorado; Alma, Byers R. S., Dillon, Elk Creek near Fraser (Grand Co.), Estes Park, Fraser. Connecticut: Richfield. District of Columbia: Wa.shington. Idaho: Coeiir d'Alene, Collins, Eagle, Em- erald Creek (Clark Co.), Payette N. F., Moscow, Oro- fino. Pierce, Sand Point, Soda Springs, Utah Co. Maine; Bmnswick, Camp Caribou, Monmouth, Norridgewock, Old Town, Paris, Portland, Waldoboro. Massachusetts; Boston, Framingham, Southboro, W. Springfield, Stone- ham. Michigan: Eagle Harbor, Grand Island, Gull Lake (Kalamazoo Co.), Marquette, Munsing. Minnesota; Du- luth, Itasca Park. Montana: Cabinet N. F., Cohmibia Falls, Missoula, Sula. New Hampshire: Durham, Fran- conia, Hanover, Manchester, Webster. New Jersey: Chester, Da Costa. New Mexico: Las Vegas. New York: Buffalo, Caroline, Cranberry Lake, Gloversville, Ithaca, Nassau, Pocono Lake, Syracuse, West Point, Wyandanch. North Carolina: Ashville, Davidson River, Hendersonville, Pink Beds, Pisgah Ridge, Southern Pines. Ohio; Chillicothe. Oregon; Grant Co., Pine. Pennsylvania: N. Bloomfield, Chambersburg, Cooks- burg, Mt. Alto, Montebello. Utah: Logan Canyon. Wolf Creek Pass. Virginia; Falls Church, Ri.xey, Vetch. West Virginia: Crow (Raleigh Co.). Dellslow, Grand Co., Hampshire Co., Monongalia Co., Morgantown, Pend- leton. Wisconsin: Lac du Flambeau, Three Lakes. Wyoming; Centennial, Lovell. Hosts.— Pinus contorta, P. flexilis, P. resi- nosa, and P. virginiana. Biology.— Basically as in r. rugipennis ex- cept the timnels are constructed in stumps and roots at or below the ground level and only rarely in the bole of fallen trees or logs. Notes.— The type and 658 other speci- mens were studied. See the above discussion under r. nigipennis concerning intergradation between this widely distributed form and the more restricted form on the Pacific Coast. This subspecies is very similar to glabratus (Zetterstedt), of Europe and Asia, which it re- sembles as closely as it does r. rugipennis. The minute and often inconsistent differences between the two forms suggest that geo- graphical races should be recognized. In spite of this, separate names are retained because the differences, though minute, are definite. The female cotype of Hylastes pinifex Fitch, U.S. National Museum type No. 42807, is here designated as the lectotype of Fitch's species. 8. Hylurgops subcostulatus subcostulatus (Mannerheim) Figs. 4()A,B Hylastes subcostulatus Mannerheim, 1853, Bull. Sec. Imp. Sci. Nat. Moscou 26(3): 239, (Holotype, sex?; Kenai Peninsula, Alaska; presumably lost) Hylastes cristatus Mannerheim, 1853, Bull. Soc. Imp. Sci. Nat. Moscou 26(3):239 Holotype, sex?; Kenai Peninsula, Alaska; presumably lost). Diagnosis.— As indicated in the above key this is the only American Hylurgops with the alternate declivital interstriae strongly ele- vated. From about central Arizona and New Mexico northward the elevations are more nearly uniform in height and the tubercles they bear are comparatively small; the popu- lation from that point southward is placed in the subspecies alternans. Male.— Length 3.1-4.2 mm, 2.5 times as long as wide; color dark reddish brown. Frons essentially as in incomptus except rostrum slightly smaller and transverse im- pression slightly deeper. Pronotum 0.90 times as long as wide; widest one-third from base, sides on basal two-thirds strongly arcuate and converging slightly, more strongly one-third from ante- rior margin, rather narrowly rounded in front; surface unarmed, densely covered by punctures of two sizes, larger ones separated by distances equal to less than diameter of a puncture, smaller ones confined to inter- spaces and about half as large as larger punc- tures. Each small puncture bearing a small, ragged scale; a few bristles on lateral margins. Elytra 1.8 times as long as wide 2.2 times as long as pronotum; sides almost straight and parallel on basal three-fourths, rather broadly rounded behind but with posterior outline in- terrupted by strongly elevated interstriae; striae slightly impressed, punctures deep; in- terstriae as wide as striae, convex, sub- crenulate toward base, odd-numbered 92 Great Basin Naturalist Memoirs No. 6 interstriae elevated toward declivity, punctures fine, close, confused, with an in- definite median row of irregularly spaced, fine granules. Declivity rather steep, convex; interstriae 1, 3, 7, and 9 abruptly, strongly elevated, about as high as wide, summit al- most uniform except where armed by a row of moderately large, pointed tubercles, 2, 4, 6, and 8 unarmed. Ground vestiture of abun- dant, small scales to base; rows of interstrial bristles visible on posterior half, each bristle short, rather stout. Body commonly covered by an incrustation. Female.— Evidently as in male except on abdominal terga. Distribution.— Alaska and Montana to northern Arizona and New Mexico. ALASKA: Kenai Peninsula. CANADA: British Colum- bia: Coldwater, Kelowma, Midday Valley, Peachland, Summerland, Vancouver. USA: Arizona: Chiricahua Mts., Coconino N. F., Coronado N. F., Grand Canyon, Huachuca Mts., Kaibab N. F., Lakeside, Prescott N. F., Santa Catalina Mts., Williams. California: Acta, Bass Lake, Big Pines Park, Blacks Mt., Blue Lake, Bumey, Charleton Flats, Chester, Dorrington, Fallen Leaf Lake, Grass Valley, Hackamore, Lassen N. F., Mather, Mead- ow Valley (Plumas Co.), Mineral, Oakland, Pollock Pines, San Diego, Sequoia N. P., Tahquitz (San Juacinto Mts.), Tnickee, Walker Mine (Plumas Co.). Colorado: Bailey, Boulder, Estes Park, Evergreen, Glennhaven, Golden, Norwood, Pingree Park, Uncompahgre N. F. Idaho: Athol (Kootenai Co.), Coeur d'Alene, Harpster Grade, Moscow, Potlatch, Smith's Ferry, Tamarack, Westmond, Whitebird. Montana: Hamilton, Sula. New Mexico: Cloudcroft, Lincoln N. F., Mt. Taylor. Oregon: Ashland, Blue Mts., Corvallis, Green Springs (Jackson Co.), Keno, Klamath Co., Santiam Pass, Sisters, Summit Prairie, Warm Springs Indian Reservation. South Da- kota: Black Hills, Custer, Hill City, Spearfish. Utah: Ashley N. F., Long Hollow (Dixie N. F.), Mammoth Mt., Sanford Canyon (Dixie N. F.). Washington: Columbia Co., Kooskooskie, Natches, Preston Creek (Wenatchee N. F.). Wyoming: Centennial. Hosts.— Evidently all species of Pinus and Picea within its range. Biology.— Most commonly taken in pros- trate trees or logs, but it will also breed in erect trees killed by other beetles. It is one of the few bark beetles that breed successfully in sour logs. Presumably the gallery system is similar to that described above for incomptus. Notes.— The above treatment was based on 420 specimens that agree with material in the U.S. National Museum and in the Cana- dian National Collection. The original material on which Mannerheim based sub- costulatus and cristatus is missing from the Helsinki Museum and is presumed lost. The descriptions are adequate to characterize this species; however, that of cristatus indicates a size of 1 lin. (2.12 mm), and for subcostulatus Wa lin. (2.65 mm), which is smaller than specimens examined during this study. In view of other measurements given by Man- nerheim, discrepancies of this magnitude might be expected. 9. Hylurgops subcostulatus alternans (Chapuis) Fig. 42C Hylastes alternans Chapuis, 1869, Synopsis des Scoly- tides, p. 22 (Mexico; Brussels .Mus.) Diagnosis.— The population of this spe- cies from central Arizona and New Mexico southward has the alternate declivital inter- spaces more strongly elevated and somewhat inflated at each tubercle arming its summit. The two widely distributed forms intergrade in a narrow belt in northern Arizona and New Mexico. Male.— Length 3.3-4.4 mm, 2.4 times as long as wide; color dark reddish brown. This subspecies differs from s. sub- costulatus only in details of elytral structure. The elevated declivital intervals are rather strongly constricted in height and width be- tween tubercles; the strial punctures are also distinctly larger. Female.— Essentially as in male except for the abdominal terga. Distribution.— Southern Arizona and southern New Mexico to Mexico (state). MEXICO: Chiapas: 14 km E San Cristobal, 31-VII-57, J. A. Chemsak. Distrito Federal: Mexico. Durango: 100 km W Durango, 5-VI-65, 2500 m. No. 28, Pinus, S. L. Wood. Guerrero: Omilteme, H. H. Smith. Mexico: 21 km W San Martin de Texmelucan, 14-VII-53, 2800 m. No. 103, Pinus, S. L. Wood. Hosts.— Evidently any species of Pinus within its range, but most common in P. pon- derosa and P. leiaphylla. Biology.— Evidently as in subcostulatus, but less commonly taken in prostrate trees or logs; usually in standing, dying trees. Notes.— The above treatment was based on 12 specimens that agree with Blandford's Biologia Centrali-Americana material. Because the zone of intergradation be- tween the subspecies of subcostulatus is in an 1982 Hylastini 93 inconvenient geographical area, and because it is gradual and rather extensive, I have arbi- trarily designated all specimens north of the Mexican border as s. suhcostulatus and all those south of the border as s. alternans. Ac- tually, those from the southern one-fourth of Arizona and New Mexico clearly are s. alter- nans, those from the northern one-fourth are s. suhcostulatus, and those from the inter- vening area usually cannot be placed with confidence in either subspecies. Genus HYLASTES Erichson Hylastes Erichson, 1836, Archiv. Naturgesch. 2(1):47 (Type-species: Bostrichiis ater PaykuU, sub- sequent designation by Westwood, 1838, Synops. Gen. British Ins'., p. 39, also by Thomson, 1859, Skand. Coleopt. synop. bearb, p. 146) Diagnosis.— This genus is very closely re- lated to Hylurgops from which some species are separated with difficulty. Characters mentioned in the above genetic key and in the diagnosis of Hylurgops serve to dis- tinguish it. Description.— Length 2.1-6.0 mm, 2.6-3.2 times as long as wide; color black ex- cept reddish brown in two species. Frons usually with a transverse impression midway between level of antennal insertion and upper level of eyes, convex above, flat- tened or weakly convex below this point, lower area often with a fine, median carina or a median groove. Eye subovate, entire. Antennal funicle 7-segmented; club conical, basal segment usually longer than others. Pronotum elongate, unarmed. Scutellum small, oval. Crenulations on elytral bases poorly developed, bases not elevated; striae rarely impressed, punctures distinct; inter- striae variously sculptured. Declivity convex, steep. Vestiture usually including scales and hair. Third tarsal segments at most emargi- nate, not bilobed. Distribution.— The Holarctic realm; 15 species occur throughout the coniferous for- ests of North and Central America south to Honduras. An additional dozen or more spe- cies occur in the coniferous forests of north Africa, Europe, and Asia. Biology.— All species breed in the phloem tissues in the stumps and roots and occasion- ally in logs of coniferous trees. The gallery systems of North American species have not been adequately studied, but are similar to those described above for Hylurgops. Key to the Species of Hylastes 1. Frons entirely devoid of a median carina; discal interstriae with punctures uniseriate (except fulgidus); small species, less than 3.0 mm (some fulgidus to 3.5 mm) 2 — Frons with a definite median carina, often restricted to area near epistoma or to central area; punctures of discal interstriae confused (except longicollis); larger than 3.3 mm 4 2(1). Interspacial areas between pronotal punctures smooth, shining, entirely devoid of reticulation; punctures on discal interstriae confused; anterior tibiae with five to eight socketed teeth; S California and SW Kansas to Michoacan; 2.8-3.5 mm 1. fulgidus Blackman — Interspacial areas between pronotal punctures partly or mostly reticulate; punctures on elytral disc usually subcrenulate or granulate, usually uniseriate; anterior tibiae with four to five socketed teeth; smaller species 3 3(2). Frons and vertex punctured, interspaces smooth to feebly granulate, median groove feebly indicated or absent; California and Hidalgo to Maryland and Florida; 2.0-2.5 mm 2. tenuis Eichhoff — Frons and vertex devoid of punctures, coarsely, closely granulate, lower half usually with a conspicuous median sulcus; Texas to North Carolina and Florida; 2.3-2.7 mm 3. exilis Chapuis 4(1). Elytral declivity devoid of scalelike vestiture; body stout, less than 2.6 times as long as wide; pronotum widest on basal fourth; strial punctures rather large, interstriae coarsely sculptured, rather narrowly convex on declivity, declivital 94 Great Basin Naturalist Memoirs No. 6 tubercles rather large; posteriorly interstriae 8 higher than 9; New Jersev and Florida to E Texas; 3.3-5.0 mm 4. salebrosus Eichhoff — Ground vestiture of elytral declivity consisting of abundant scales (except ru- ber); body more slender, 2.8 or more times as long as wide; pronotum widest at or in front of middle; strial punctures usually smaller, interstriae more broadly rounded, more finely sculptured, declivital tubercles fine 5 5(4). Strial punctures on disc subrectangular, noticeably longer than wide, much wider than interstriae; interstrial punctures uniseriate; hairlike setae on elytral declivity more abundant than scalelike setae; California and British Columbia to South Dakota; 3.3-3.9 mm 5. longicollis Swaine — Strial pimctures on disc circular or at least wider than long; interstriae usually at least as wide as striae, their punctures confused; scalelike setae on declivity much more abundant than hairlike setae; last visible female sternum normal, convex, in male medially impressed and ornamented by fine, often dense pubescense; female pronotum normally more slender; larger species 6 6(5). Premandibular epistomal process large, usually narrowly emarginate, bilobed, lateral apical margins conspicuously elevated, concavity between them contin- uous with impressed area extending to near antennal insertions, median carina not divided at its lower extremity; elytral vestiture largely hairlike on declivi- ty, scalelike setae sparse or entirely absent; body color reddish brown; Northwest Territories and Alberta to Arizona; 4.8-5.2 mm 6. ruber Swaine — Premandibular epistomal process sinuate at most, its lateral apical margins not elevated; median frontal carina forked at lower end, a ridge or costa contin- uing to near lateral apices of epistomal lobe, median portion of lobe hemi- spherically or subtriangularly impressed or excavated below costae and bearing a specialized tuft of hairlike setae; vestiture on elytral declivity consisting of abundant scales; body color dark brown to black; male sternum 5 flattened or medially impressed and ornamented by numerous setae 7 7(6). Fore tibia armed by six teeth, basal half of tibia rather slender; hind tibia with two teeth on lateral margin before angle; pronotum not reticulate (except toward margins in porculus); usually smaller than 4.0 mm except those from Mexico 8 — Fore tibia armed by seven or eight teeth (rarely six), basal half of tibia stout; hind tibia with three or four teeth on lateral margin before angle; pronotum at least partly reticulate in most specimens; usually larger than 4.0 mm 12 8(7). Pronotal punctures fine, deep, interspaces averaging about as wide as a pimc- ture; striae, narrower, interstriae about one and one-half times as wide; punc- tures on head finer, usually regular and not confluent; color black; Mexico; larger than 4.2 mm 9 — Pronotal punctures coarse, interspaces averaging about half as wide as a punc- ture; striae wider, almost as wide as interstriae; frontal area coarsely punctured; brown to black 11 9(8). Discal strial pimctures very small, shallow, interstriae three or more times as wide as striae; interstrial punctures almost as large as those of striae; declivital striae slightly impressed, punctures larger and deeper than those of disc, inter- striae three times as wide as striae; Hidalgo to Morelos; 4.8 mm 7. flohri (Eggers) — Discal strial punctures rather coarse, deep, interstriae less than twice as wide as striae; discal punctures of striae at least twice as large as those of interstriae; strial pimctures on declivity not larger than those on disc 10 1982 Hylastini 95 10(9). Declivital striae feebly or not at all impressed, punctures coarse, deep, about equal in width to interstriae; interstrial tubercles on declivity more widely spaced, separated by distances about equal to width of an interstriae; Arizona and Durango to Mexico; 4.2-4.9 mm 8. mexicanus Wood — Declivital striae narrowly impressed, punctures fine, widely spaced; declivital interstriae at least three times as wide as striae, tubercles close, spaced by dis- tances equal to less than half width of an interstriae; punctures on head minute; Hidalgo; 4.3 mm 9. niger Wood 11(8). Pronotal surface of interspaces smooth, shining; pronotal punctures smaller, more uniformly distributed; British Columbia and Montana to Guatemala; 3.3-4.0 mm 10. gracilis LeConte — Pronotal interspaces at least partly reticulate in marginal areas (rarely entirely shining); pronotal punctures larger, more irregularly placed; Manitoba and New Brunswick to Texas and Florida; 3.8-5.0 mm 11. porculus Erichson 12(7). Discal interstriae finely crenulate to declivity; declivital interstriae armed by small, pointed tubercles; pronotum very closely, deeply punctured; Arizona and New Mexico; 4.0-4.6 mm 12. asperatus Wood — Discal interstriae usually irregular but not crenulate; pronotum less coarsely punctured; declivital interstriae usually unarmed or minute tubercles confused (except most macer) 13 13(12). Entire surface of elytra and pronotum minutely reticulate, dull; interstriae ten- ding to be very slightly wider than striae, less strongly convex, the surface less irregular, punctures finer and as much as irregularly three ranked; British Co- lumbia and California to South Dakota and Arizona; 5.1-6.0 mm 13. macer LeConte — Surface of elytra smooth, shining; interstriae tending to be slightly narrower than striae, more convex and irregular, punctures larger and mostly uniseriate or two-ranked; usually stouter and slightly smaller 14 14(13). Striae usually wider than interstriae; interstrial punctures rather coarse; reti- culation on pronotum usually less evident, punctures larger; female body 3.0 times as long as wide; in Pinus; Alaska and California to W. Montana; 3.8-4.9 mm 14. nigrinus (Mannerheim) — Striae usually narrower than interstriae; interstrial punctures finer; reticulation on pronotum clearly evident, punctures slightly smaller; female body stouter, 2.8 times as long as wide; Abies; Utah and Wyoming to New Mexico; 4.4-5.5 mm 15. subopacus Blackman 1. Hylastes fulgidus Blackman Female.— Length 2.8-3.5 mm, 2.8 times as I, I r 7 .J r,, . ,r^-, ,T r^ r^ . loug as widc; color black. Hylastes fitlgiaiis, Blackman, 1941, U.S. Dent. Aeric. ^ ^ ^^ ^ i . i Misc. Pub. 417:18 (Holotvpe, female; Las Vegas ^^^ons shallowly, transversely impressed Hot Springs, New Mexico; U.S. Nat. Mus., 540.3.5) just below upper level of eyes, convex above Diagnosis.— This species is allied to tenuis and slight inflated below this point, trans- Eichhoff, but it may be distinguished by the versely impressed just above epistomal mar- larger size, by the smooth, shining frons with gin except at median line; surface reticulate nongranulate punctures, by the smooth, shin- on lower half, punctures rather fine, close, ing, nonreticulate pronotum having some- deep; vestiture inconspicuous, what smaller punctures, and by the more Pronotum 1.2 times as long as wide; widest abundant declivital scales. As in tenuis the near middle, sides moderately arcuate, rather frons is completely devoid of a median narrowly rounded in front; surface smooth carina. and .shining, punctures large, deep, close, 96 Great Basin Naturalist Memoirs No. 6 smaller on anterior third; median line obscurely indicated. Elytra 1.9 times as long as wide, 1.8 times as long as pronotum; sides almost straight and parallel on basal three-fourths to declivital base, broadly rounded behind; striae feebly if at all impressed, punctures moderately large, deep; interstriae as wide as striae, feebly con- vex, punctures rather coarse, confused, not at all granulate. Declivity convex, steep; inter- striae slightly wider than striae, granules not evident. Discal vestiture hairlike, short, rather abundant; on declivity of rather abun- dant scalelike ground cover and rows of long- er bristles. Male.— Distinguishable from female only by abdominal terga. Distribution.— California and SW Kansas to Baja California and Michoacan. USA: Arizona: Cave Creek in Chiricahua Mts., 21-VI- 58; Rustler's Park in Chiricahua Mts., 5-VII-40, R. H. Beamer; Huachuca Mts.; Hualpai M., 6-VII-38, J. N. Knull; Prescott N. F., 8-V1I-59, Pinus ponderosa. Califor- nia: Chuchupate R. S. (Ventura Co.), 9-V-59, C. W. O'Brien; Mt. Diablo, 15-III-47, R. Coleman; Northfork, 25-III-26; O'Neal (Madera Co.), 16-III-47, A. T. McClay. Colorado: New Castle, Hopk. US .31408-28. Kansas: Wallace Co. Nevada: Beaver Dam St. Pk. (Lincoln Co.). New Mexico: Cloudcroft, 27-VI-40, flight, R. H. Bea- mer; Edgewood, B-1296, C. C. Hoff; Gallup; Las Vegas, 9-VII; Los Alamos, 10-11-58, Pinus edulis. MEXICO: Baja California: Sierra San Pedro Martir at La Sanja, 28- V-58, J. Powell. Chihuahua: La Laja, 16-VI1-60, flight, S. L. Wood; 26 km NE San Juanito, 19-V1I-60, flight. S. L. Wood. Durango: .50 km SW El Salto, 23-V1I-53, flight, S. L. Wood. Mexico: Amecameca. Michoacan: Maza- mitla, 24-VII-53, C. and P. Vaurie. Morelia: Calpulapan. Zacatecas: 6 km W Monte Escondido, 2600 m, flight, R. H. Beamer; "Durango," VIl-53. Hosts.— Pinus edulis, P. ponderosa, and presumably P. spp. Biology.— Unknown; presumably it infests stumps or roots. Evidently most or all the above specimens were taken in flight. Notes.— The above treatment was based on the holotype and on 49 other specimens. 2. Hylastes tenuis Eichhoff Fig. 204 Hylastes tenuis Eichhoff, 1868, Berliner Ent. Zeitschr. 12:147 (Syntypes ?; Amerique Boreale; presum- ably lost with the Hamburg Mus.) Hylastes criticus Eichhoff, 1868, Berliner Ent. Zeitschr. 12:147 (Two syntypes; .'\merique Boreale; pre- siunablv lost with the Hamburg Mus.); Blackman, 1941, U.S. Dept. Agric. Misc. Pub. 417:22. Synonymy Hylastes pusillus Blackman, 1941, U.S. Dept. .\gric. Misc. Publ. 417:23 (Holotype, female; Florida; U.S. Nat. Mus., .540,36); Wood, 1971, Great Basin Nat. 31:146. Synonymy Hylastes parvus Blackman, 1941, U.S. Dept. Agric. Misc. Publ. 417:24 (Holotype, female; Williams, .Ari- zona; U.S. Nat. Mus., 54037); Wood, 1971, Great Basin Nat. 31:146. Synonymy Hylastes minutus Blackman, 1941, U.S. Dept. Agric. Misc. Publ. 417:25 (Holotype, female; Lake Tahoe, Nevada; U.S. Nat. Mus., 54038); Wood, 1971, Great Basin Nat. 31:146. Synoni/mi/ Diagnosis.— This species is very closely related to attenuatus Erichson, of Europe, from which occasional specimens from the Atlantic Coast states are distinguished with difficulty. Among American species it is al- lied to fulgidus Blackman, from which it is easily distinguished by characters included in the above key. Female.— Length 2.1-2.7 mm, 3.0 times as long as wide; dark brown to almost black. Frons with a weak, transverse impression just below upper level of eyes, convex above and slightly inflated below this point, trans- versely impressed immediately above epis- tomal margin except at median line; middle third of median line often narrowly im- pressed; surface coarsely, rather shallowly punctured, fundus of each puncture reti- culate at least on upper half of frons; vesti- ture inconspicuous. Pronotum about 1.2 times as long as wide; widest on basal half, sides weakly arcuate, broadly rounded in front; surface reticulate except toward median line, with coarse deep punctures. Elytra 1.9 times as long as wide, 1.8 times as long as pronotum; sides almost straight and parallel on basal two-thirds to declivital base, rather narrowly rounded behind; striae 1 weakly, others not impressed, punctures large, deep; interstriae as wide as striae, feebly convex, each bearing a uniseriate row of fine, rounded, setiferous granules. Declivi- ty narrowly convex, slope rather gradual on upper half, steep below; sculpture essentially as on disc. Vestiture consisting of interstrial rows of short, hairlike bristles, somewhat longer on declivity; and, on disc, supplemen- tal rows of scales may be present, usually not more than one row on each interstrial margin. Male.— Except for abdominal terga con- sistent differences not apparent. 1982 Hylastini 97 Distribution.— California, and New York to Hidalgo and Florida. USA: Alabama: Horn Mt., Mobile, Montomery. Ar- kansas: Bradley Co. Arizona: Bahoguivari Mt. (Pima Co.), Chiricahua Mts., Flagstaff, Hiialpai M., Jacob's Lake, Oak Creek Canyon, Prescott N. F., Williams, Winslow. California: Bass Lake, Big Basin (San Mateo Co.), Carmel, Carrville, Grass Valley, Miami, Mokel Hill (Calavaras Co.), Mt. Laguna (Cleveland N. F.). District of Columbia: Washington, Woodridge. Florida: Lake Placid, Key West, Monticello, Sebring. Georgia: Clay- ton. Idaho: Nez Perce. Kentucky: Irving (Estill Co.), Knox Co. Louisiana: Bogalusa, Elizabeth. Maryland: Beltsville, Hyattsville, Oldenton, Plumbers Island, Plimi Point, Travilah. Massachusetts: Framingham. Mis- sissippi: Ocean Springs. Nevada: Lake Tahoe. New Jer- sey: Beach Haven. New Mexico: Las Vegas. New York: New York, Yaphank (Long Island). North Carolina: Ash- ville. Black Mt., Chadbourn, Durham, Gray Beard Mt., Lake Toxaway, Pink Beds, Pishgah Bidge, Southern Pines, Swannanoa Valley, Tryon, Whitesides Mt. (High- lands). Pennsylvania: Clark's Valley, Cold Springs (Adams Co.), Hummelstown, Mamada Gap, University Park. South Carolina: Aiken, Florence, Myrtle Beach. Tennessee; Chilhowee. Texas: Big Bend, Call. Utah: Zion N. P. Virginia: Camp Pickett, Ft. Monroe, Nelson Co., Virginia Beach, West Point. West Virginia: Ka- nawha Station, Morgantown, Roncevert, West Sulphur. MEXICO: Hidalgo: Jacala. Mexico: San Rafael. Hosts.— Evidently any species of Pinus within its range; less commonly from other conifers. Biology.— Largely unknown, presumably a root-infesting species. Notes.— The types of tenuis and criticus were examined by J. M. Swaine prior to their loss and compared to material in his collec- tion. The above treatment was based on my material that agrees with Swaine's specimens and that was compared to holotypes of pu- sillus, parvus, and minutus. The features de- scribed by Blackman for the species treated here as synonyms appear to be normal varia- tions. There are numerous minute variations within a series involving the shape of the pronotum, appearance of the elytral surface, and vestiture. Some of these variations result from abrasion. In all, 279 specimens were ex- amined, 88 of them were from the western United States. 3. Hylastes exilis Chapuis Hylastes exilis Chapuis, 1869, Synopsis des Scolytides, p. 20 (Holotype, sex?; "Nuorlean," presumably New Orleans, Louisiana; Brussels Mus.) Diagnosis.— This species is distinguished from tenuis Eichhoff by the slightly larger average size, by the rather coarsely granulate frons and vertex that are devoid of punctures, by the distinct median groove on the frons, and by the very slightly larger (variable) ely- tral crenulations. Female.— Length 2.3-2.7 mm, 2.8 times as long as wide; color black. Frons as in tenuis except transverse im- pression at middle more di.stinct, median sul- cus on lower half always distinctly impressed, and surface devoid of punctures, rather close- ly, coarsely granulate above transverse im- pression, more finely granulate on lower half. Pronotum and elytra as in tenuis except in- terstrial crenulations average very slightly larger, slightly confused, often closer (variable). Male.— Similar to female in all respects; presence of declivital interstrial scales possi- bly restricted to males. Distribution.— Texas to North Carolina and Florida. US.\: Alabama: Conecuh, 7-XI-6L P- palustris, E. I. Hazard. Arkansas: Texarkana, 26-III-07, W. D. Pierce. District of Columbia: Washington, V, Hubbard and Schwartz. Florida: Flagler Co., 12-X-77, P. elliotii, T. H. Atkinson; Lake Placid, 13-VII-48, R. H. Beamer; Lake Worth, 1889, L. B. Parker; Sebring, 20-VI-51, at light, S. L. Wood; Vero Beach, 15-11-14, flight, G. G. Ain.selle. Louisiana; Elizabeth, VII-IX-67, PirMis taeda. Mis- sissippi: Lucedale, 28-IV-29, H. Dietrich.; Starkville, 19- V-20, M. W. Blackman. North Carolina: Chapel Hill, 28-IV-29, H. Dietrich; Chadbourn, 20-IV-lO. E. G. Smith; Southern Pines, 19-IV-17, A. H. Mantee. South Carolina: BishopviUe, 17-IV-61, V. M. Kirk; Myrtle Beach, 22-IV-57, ll-IV-62. V. M. Kirk. Texas: Kirbyville, 2-III-08, E. S. Tucker. Hosts.— Pinus elliotii, P. plaustris, P. taeda, and probably other P. spp. Biology.— Not recorded. It probably breeds in the stumps and roots of pine trees. Most specimens were collected in flight in pine forests. Notes.— The above treatment was based on the holotype and on 21 other specimens. 4. Hylastes salebrosus Eichhoff Hylastes salebrosus Eichhoff, 1868 (May), Berliner Ent. Zeitschr. 12:146 (Lectotype, male; Carolina; U.S. Nat. Mus., present designation) Hylastes scohinosiis Eichhoff. 1868 (May), Berliner Ent. Zeitschr, 12:146 (Syntypes?, sex?; Carolina pre- sumably lost in the Hamburg Museum.). New Synonymy Hylurgus scabripennis Zimmermann, 1868 (September), Trans. Amer. Ent. Soc. 2:149 (Syntypes; Atlantic States; Mus. Comp. Zool.); Blandford, 1898, Ent. News 9:5. Synonymy 98 Great Basin Naturalist Memoirs No. 6 Diagnosis.— This species is not closely al- lied to any species known to me. It differs from all other Hijlastes species in having the elytral vestiture hairlike, scales are entirely absent; punctation of the pronotum is more nearly like the Rhyncolini than Hylastes; and the declivital interstriae are much more coarsely tuberculate than in other Hylastes. Female.- Length 3.3-5.0 mm, 2.4-2.5 times as long as wide; color black. Frons weakly, transversely impressed just below upper level of eyes, more strongly, broadly, transversely impressed just above epistomal margin; epistomal lobe poorly de- veloped; median carina rather poorly devel- oped but usually distinct on its upper half; surface rather finely, obscurely punctured on lower half, becoming rather coarsely granu- late above. Pronotum 1.05 times as long as wide, widest at base, sides arcuately converging to weak constriction just behind broadly rounded anterior margin; surface smooth with rather small, deep punctures, their size decreasing on anterior third; spaces between punctures variable but usually slightly less than diameter of a puncture. Elytra 1.5-1.6 times as long as wide, 1.8 times as long as pronotvim; sides very feebly arcuate to declivital base then somewhat nar- rowly rounded behind; striae impressed, punctures rather small, distinct; interstriae one and one-half times as wide as striae, con- vex, surface subshining, with transverse lines through irregular, confused punctures, more nearly subcrenulate toward base and declivi- ty. Declivity convex, moderately steep; inter- strial crenulations close, tuberculate, in rows. Vestiture largely confined to declivity; short, fine middle row on each interstriae slightly stouter but usually not longer. Male.— Similar to female except last vis- ible abdominal sternum flattened or weakly impressed toward median line, not convex as in female. Distribution.— New Jersey and Texas to Florida. USA: Alabama: Altniore, Mol)ilc. Florida: Biscavnc Bay. (Jainsville, Montacello, Sncad, Siiwance Springs. Georgia: Atlanta, Clayton. Loui.siana: Bogaliisa. Mary- land: Beltsville. Mi.ssissippi: Liicedale. New Jersey: Lakewood, Sominerset C:o. North Carolina: .\shville, Camp Pickett, Pink Bed.s, Fi.sgah Ridge, Southern Pines, Swannanoa Valley, Trvon. South Carolina: Clemson College, Florence, Lumber. Texas: Call, Willis. Virginia: Cape Charles, Enterprise, Ft. Monroe, Nelson Co. Hosts.— Presumably all species of Pinus within its range. Biology.— This species evidently breeds in stumps or in roots well below ground level. Because newly emerged adults have been taken from seedlings, it is possible that a feeding on green host tissues is necessary for maturation. Adults sometimes are attracted in large numbers to green lumber at sawmills. Notes.— Two cotypes of salehrosus, a male and a female, in the U.S. National Mu- seum apparently are the only existing speci- mens of the original series. I, therefore, here designate the first specimen, a male, as the lectotype of salehrosus Eichhoff. A female specimen in the U.S. National Museum re- ceived from Eichhoff and labeled as a cotype of scobinosus is from "Tennese" (sic) and cannot be regarded as a member of the origi- nal type series; however, because it was ex- amined by Eichhoff it is used as the basis for placing this name in synonymy. In addition to these, 151 specimens were examined dur- ing this study. 5. Hylastes longicollis Swaine Hylastes longicollis Swaine, 1918, Dom. Canada Dept. Agric. Ent. Br. Bull 14(2):79 (Holotype, sex?; At- lanta, Idaho; Canadian Nat. Coll.. 9246) Diagnosis.— The structure of the epistom- al process, the paucity of elytral scales and the light body color indicate a relationship to ruber Swaine and distinguish these species from other Hylastes. The small size and the large, quadrate punctures distinguish it from ruber. Female.— Length 3.0-3.9 mm, 2.9 times as long as wide; color moderately dark reddish brown. Frons with tran.sver.se impression just be- low upper level of eyes very poorly devel- oped, subinflated at level of antennal in- sertion, epistomal margin rather narrowly impressed; epistomal lobe wide, poorly de- veloped, devoid of a pair of elevations ex- tending to median carina; a fine, acutely ele- vated carina extending on lower half from transverse impression to near base of epis- tomal lobe; surface rather coarsely, shallowly punctured; vestiture consisting of .short hair. Pronotum 1.22 times as long as wide, widest just in front of middle; sides straight 1982 Hylastini 99 and diverging slightly on basal half, rather broadly rounded in front; surface smooth, shining, with very coarse, moderately deep punctures, their inner surfaces subreticulate, interstriae equal to less than half diameter of a puncture; median line evident on middle half; vestiture consisting of fine, moderately short hair over entire surface. Elytra 1.93 times as long as wide, 1.9 times as long as pronotum; sides almost straight and parallel to declivital base, narrowly rounded behind; striae not impressed, punctures coarse, mostly longitudinally subrectangular; interstriae about half as wide as striae, punc- tures fine, subgranulate on anterior lip, al- most uniseriate. Declivity narrowly convex, moderately steep; striae about as wide as in- terstriae. Vestiture consisting of short, rather fine interstrial hair on disc, becoming stout on declivity and with an indefinite row of slender scales on each margin of each interstriae. Male.— Similar to female except body evi- dently a little stouter, with the last visible ab- dominal sternum slightly flatter and shorter (very indefinite). Distribution.— British Columbia and Al- berta to California and South Dakota. CANADA: Alberta; Cypress Hills, l-VI-25, F. S. Carr. British Columbia: Aspen Grove, 23-VI-33, Pinus con- torta, K. Graham; Cranbrook; Emerald Lake; Creston, 31-V-56, G. S. Smith; Lorna, 29-VI-24, G. Hopping; Merritt (Midday Valley), 7-VI-25, P. ponderosa, J. Stanley; Pender Harbor, lO-V-28, G. R. Hopping; Ter- race; Trinity Valley, 18-V-28, J. R. Howell. USA: Califor- nia; Giant Forest (Tulare Co.), 19-VII-15, 3200 m, R. Hopping; Lake Tahoe; Lodgepole Camp (Sequoia), 24- VI-48, A. T. McClay; Meadow Vallev (Plumas Co.), 26- VI-.30; Miami R. S. (Mariposa Co.), 20-V-42, A. J. Walz; Round Meadow Giant Forest (Tulare Co.); White Cloud Camp (Nevada Co.), .30-V-65, P. Arnaud. Idaho: Coeur d'Alene, 20-VI-.36, P. monticola, T. O. Thatcher; Idaho City, 26-V-70, trap; Kootenai Co., 19-VI-68, trap; Kras- sel R. S., 14-VL66, flight, M. M. Furniss; McCall, 14-Vl- 31, M. A. Cazier; Robinson Lake (Latah Co.), 11-VL53, R. .\bbott. Montana: Columbia Falls, 18-V-lO, J. Brun- ner; St. Regis, 25-V-70, P. contortu, M. D. McGregor. Oregon: Clackamas Co., 2.5-Vn-66; Hood River; Marv's Peak, 19-VL6L flight, S. L. Wood; Prineville, Vin-35, P. ponderosa, W. J. Buckhorn; Tollgate, 8-VL31, McLane. South Dakota; Black Hills, Hopk US63.51). Washington; Mt. Baker N. F., 15-VII-35, A. M. Holland; Quilcane. 26-VL.3.5. flight. R. L. Furniss; Olympic N. P., 18-Vn-66. Hosts.— Pinus contorta, P. monticola, P. ponderosa. Biology.— It has been taken from stumps at or below the ground level. Notes.— The above treatment was based on my female homotype from Coeur d'Alene N. F., Idaho, and 129 additional specimens. 6. Hylastes ruber Swaine Hijlastes ruber Swaine, 1915, Canadian Ent. 47:.367 (Holotype, sex?; Golden, British Columbia; Cana- dian Nat. Coll. 9245) Diagnosis.— This species is rather closely allied to longicollis Swaine, but it is ea.sily distinguished by the larger size, by the small- er, circular strial punctures, and by the con- fused interstrial punctures. Female.— Length 4.8-5.2 mm, 2.8 times as long as wide; color reddish brown. Frons with transverse interocular impres- sion very weak, subinflated near level of an- tennal insertion, narrowly, transversely im- pressed immediately above epistomal margin; epistomal lobe wide, rather large, not rein- forced by a pair of ridges extending to me- dian carina; median carina acutely elevated from interocular impression to a point just above base of epistomal lobe, its lower end not forked; surface coarsely, closely, rather deeply punctured; vestiture hairlike, short, inconspicuous. Pronotum 1.12 times as long as wide; widest at or just behind middle, sides arcuate from base to feeble constriction just behind rather broadly rounded anterior margin; sur- face smooth, shining, punctures coarse, close, their centers subreticulate, interspaces less than half diameter of puncture; punctures on anterior fifth reduced in size, their inter- spaces here commonly reticulate; median line indicated on about middle three-fourths; hairlike vestiture minute, usually completely abraded. Elytra 1.8 times as long as wide, 1.9 times as long as pronotum; sides almost straight and parallel on basal three-fourths to declivital base then rather broadly rounded behind; striae feebly if at all impressed, punctures circular, moderately large, deep; interstriae as wide as striae, punctures minute, confused, very finely granulate or subgranulate. Decliv- ity convex, steep, striae moderately im- pressed; interstriae convex, tubercles larger. Vestiture consisting of minute, semi- recumbent hair. 100 Great Basin Naturalist Memoirs No. 6 Male.— Similar to female except body evi- dently slightly stouter and last visible abdom- inal sternum somewhat flattened and shorter. Distribution.— Northwest Territories and Alberta to Arizona. CANADA: Alberta: Bow River. British Columbia: Cranbrook, 29-VI-20, G. Garrett; Creston, 15-V-53, 21- VI-55, G. S. Smith; Copper Mt., 20-V-28, G. S. Smith; Kokanee Mt., London Hil! Mine on Bear Lake, 21-Vn- 03; Trinity Valley, 15-V-27, W. Mathers; Vancouver, 2()- VI-.39, H.' B. Leech; Vernon, 20-VI-39, H. B. Leech. Northwest Territories: Aklavik, 20-VIII-30, O. Bryant. USA: Arizona: Hanagan Camp (Greenlee Co.), 12-Vn- 68, D. E. Bright. Idaho: Idaho City, 26-V-7L trap, M. M. Fumi.ss; Kootenai Co., lI-VII-68, trap, M. M. Fur- niss; Krassel, V-58, Douglas fir, M. M. Furniss, McCall; Rocky Point (Benewah Co.), 23-VI-64, R. W. Portman; M0.SC0W, .30-V-3L P. Rice. Montana: Coliunbia Falls; Kalispell, 18-V-20. Oregon: Bear Springs (Wapinita), .30- VI-41, K. M. Fender; Clear Lake, 15-VI-45, K. M. Fend- er; Clackamas Co., 2.5-VII-66; Hood River, 20- V; Pacific City, 21-VII-42, K. M. Fender; Tollgate. Washington: Buckeye; Easton; Omak, 7-VII-66; Satsop River, VIII-32; Seattle, 8-V-60; Walla Walla, 9-V-36, E. W. Jones. Host.— Pseudotstiga menziesii. Biology.— Evidently restricted to the stumps and roots of the host tree. The habits evidently are similar to those of other Hylastes. Notes.— The above treatment was based on the holotype and on 134 other specimens. 7. Hylastes flohri (Eggers) Hylurgops flohri Eggers, 1926, Ent. Blatt. 26:166 (Holo- type, female; Mexico; Berlin Zool. Mus.) Hylastes flohri: Wood, 1966, Great Basin Nat. 26:24. Diagnosis.— This species is rather closely allied to mexicanns Wood, from which it is rather easily distinguished by characters sum- marized in the above key. Female.— Length 4.8 mm, 2.8 times as long as wide; color black. Frons with interocular transverse impres- sion shallow, broad, rather well developed; weakly inflated at level of antennal insertion, rather broadly impressed above epistomal margin; surface rather coarsely, closely, rather deeply punctured; median carina fine, weakly elevated from interocular impression to base of epistomal lobe, where it forks (ob- scure) and elevations continue to poorly de- veloped epistomal lobe; vestiture minute, ob- scure, hairlike. Pronotum 1.1 times as long as wide; widest at base, sides on basal two-thirds almost straight and converging slightly toward rather broadly rounded anterior margin; sur- face smooth and shining, punctures small, deep, reduced anteriorly, interspaces irregu- lar but usually at least equal to diameter of a puncture; median line not evident; glabrous. Elytra about 1.8 times as long as wide, 1.8 times as long as pronotum; outline as in mexi- canus; striae 1 weakly others not impressed, punctures very small, not clearly impressed; interstriae three to four times as wide as striae, surface irregular, shining, punctures moderately abundant, fine, confused, almost as large as those of striae. Declivity convex, rather steep; striae rather weakly impressed, punctures small but much larger than on disc; interstriae subshining, about three times as wide as striae, each with a row of fine, rounded granules almost in uniseriate rows. Vestiture confined to declivital interstriae, consisting of small, moderate to sparse scales and median rows of equally short, coarse hairlike setae. Distribution.— Hidalgo to Morelos. MEXICO: Distrito Federal: Km 43 on Highway 95. Hidalgo: .30 km E Tulancingo, lO-VII-67, 2100 m, Pinm, S. L. Wood. Mexico: .\mecameca, Parque Zoquiapan. Morelos: Km 44 on Highway S-082. Host.— Pinus sp. Biology.— Two specimens were taken just entering the phloem tissues on the lower side of a pine log 40 cm in diameter. It is pre- sumed their habits resemble those of other Hylastes. Notes.— The above treatment was based on the female holotype and on nine other specimens. The labels on the type include "Sal.," "Salizar, Rohr," "Coll. J. Flohr." 8. Hylastes mexicanus Wood Hylastes mexicanus Wood, 1967, Great Basin Nat. 27:36 (Holotype, female; 62 km west Toluca, Mexico, Mexico; Wood Coll.) Diagnosis.— The very fine, deep, pronotal punctures and the narrower striae distinguish this species and flohri Eggers from other rep- resentatives of the genus. This species is also distinguished from flohri by characters sum- marized in the above key. Female.— Length 4.3-4.5 mm, 2.8 times as long as wide; color black. Frons convex, with a weak, transverse im- pression between eyes and more strongly im- pres-sed just above epistoma; median carina inconspicuous, more strongly elevated below 1982 Hylastini 101 level of antennal insertion, continuing dorsad as a fine line to interocular impression, lower end forked; surface smooth and shining above, rather dull below, very finely, deeply, closely punctured; vestiture minute, incon- spicuous, convering entire surface. Pronotum 1.1 times as long as wide; sides widest on basal third, but almost parallel to a point just anterior to middle then broadly, evenly rounded to anterior margin; surface smooth and shining, with punctures fine, deep, close, separated by distances about equal to their own diameters; median line not evident; glabrous. Elytra 1.9 times as long as wide, 1.9 times as long as pronotum; sides straight and paral- lel on basal half, then increasingly arcuate to rather narrowly rounded posterior margin; striae 1 moderately, others weakly impressed, punctures small, deep; interstriae as wide as striae, feebly convex, subshining, punctures rather coarse, close, deep, confused, their di- ameters often only slightly smaller than those of striae. Declivity convex, steep; striae 1 weakly impressed, as wide as interstriae, punctures coarse, deep; interstriae each with a row of fine tubercles; surface reticulate. Vestiture confined to declivity, stout, con- sisting of small scalelike setae except for me- dian rows of equally short hairlike bristles on each interstriae. Male.— Similar to female except frons narrower, and last visible abdominal sternum impressed medially and pubescent. Distribution.— Arizona and Durango to Mexico (Estado). USA: Arizona: Carr Canvon, Cochise Co., 23-VII-68, D. E. Bright. MEXICO: Durango: 16 km W El Salto, VII-64, flight, J. B. Thomas. Mexico: 62 km VV Toluca, 15-VII-53, 2600 m, Pinus, S. L. Wood. Morelos: Tres Marias, Wickham. Biology.— Specimens were collected at the base of a large pine tree. Presumably they have habits similar to other Hylastes. Notes.— The above treatment was modi- fied from the original description based on the type series of 69 specimens, and on about 300 other specimens from the same locality. 9. Hylastes niger Wood Hylastes niger Wood, 1974, Brighani Young Univ. Sci. Bull., Biol. Ser. 19(1 ):7 (Holotype, male; 31 km E Tulancingo, Hidalgo, Mexico; Wood Coll.) Diagnosis.— This species is distinguished from mexicanus Wood by the narrowly im- pressed declivital striae with the punctures much smaller, and by the much more closely spaced granules on the declivital interstriae. Male.— Length 4.3 mm, 2.7 times as long as wide; color black. Frons and pronotum as in mexicanus ex- cept frons less distinctly reticulate, pronotum with punctures distinctly smaller. Elytra as in mexicanus except strial punc- tures much smaller, interstriae twice as wide as striae on di.sc, almost three times as wide on declivity; declivity not as steep; interstrial granules on declivity much more closely spaced, spaced by distances equal to less than half width of an interstriae. Female.— Similar to male except frons more finely punctured; anterior discal area of pronotum with punctures reduced to almost obsolete. Distribution.— Hidalgo. MEXICO: Hidalgo: 30 km E Tulancingo, lO-VII-67, 2100 m. No. 185, Pinus, S. L. Wood; Zacualtapan. Biology.— Two specimens were taken from the same new tunnel on the lower side of a log 60 cm in diameter. Notes.— The above treatment was based on the holotype, allotype, and eight other specimens. 10. Hylastes gracilis LeConte Fig. 43 Hylastes gracilis LeConte, 1868, Trans. Amer. Ent. Soc. 2:174 (Lectotype, female; Tahoe Valley, Califor- nia; Mus. Comp. Zool., 958, designated by Wood, 1971, Great Basin Nat. 31:145.) Hylastes vastans Chapuis, 1869, Synopsis des Scolytides, p. 17 (Holotype, female; Mexico; Brussels Mus.); Wood, 1971, Great Basin Nat. 31:145. Synonymy Hylastes longus LeConte, 1876, Proc. .\mer. Philos. Soc. 15:388 (Holotype, female; Colorado; Mus. Comp. Zool.); Wood, 1972, Great Basin Nat. 32:195. Synonymy Hylastes nitidus Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1): 19 (Holotype, sex?; Las Vegas, New Mexico; Canadian Nat. Coll.); Wood, 1971, Great Basin Nat. 31:145. Synonymy Hylastes asper Swaine, 1917, Dom. Canada Dept. .\gric. Ent. Br. Tech. Bull. 14(1): 19 (Holotype, female; Larimer Co., Colorado; Canadian Nat. Coll., 9244); Wood, 1975, Great Basin Nat. .35:22. Synonymy Diagnosis.— This small, widely dis- tributed, common species is distinguished 102 Great Basin Naturalist Memoirs No. 6 from allied species by the dark brown color, by the size, and by other characters summa- rized in the above key. Occasional specimens are distinguished from fulgidus Blackman with difficulty. Female.— Length 3.3-4.0 mm, 3.0 times as long as wide; color dark brown. Fronx convex, interocular, transverse im- pression weak, weakly subinflated at level of antennal insertion immediately above narrow epistomal impression; surface shining, close- ly, coarsely, deeply punctured; median carina usually extending from interocular impres- sion to base of epistomal lobe, fine, acutely elevated to very obscure, in some specimens either dorsal or ventral half may be obsolete; vestiture short, rather abundant, stout. Fig. 43. Ht/ldstcs gmcilis: Dorsal aspect, (.\fter Bright and Stark 1973:147.) Pronotum 1.19 times as long as wide; widest at middle, sides weakly arcuate, al- most parallel on basal two-thirds, not con- stricted before broadly rounded anterior mar- gin; surface smooth, shining, punctures moderately coarse, deep, separated by inter- spaces equal to not more than diameter of a puncture (usually less); glabrous. Elytra 1.9 times as long as wide, 1.9 times as long as pronotum; sides almost straight and parallel on basal three-fourths to declivital base, then rather narrowly rounded behind; striae 1 weakly, others not impressed, punc- tures coarse, deep; interstriae as wide as striae, almost .smooth, punctures fine, almost uniseriate. Declivity convex, rather steep; strial punctures slightly larger than on disc; interstriae weakly convex, each armed by a row of fine granules. Vestiture consisting of fine hair on disc, becoming moderately abun- dant, slender scales on declivity. Male.— Similar to female except very slightly stouter, and with last visible abdomi- nal sternum impressed and pubescent in me- dian area. Distribution.— British Columbia and South Dakota to (probably) Honduras. CA.\,\DA: British Columbia: Creston, Merritt (Mid- day Valley), Newgate, Oliver, Siimmerland. US.\: Ari- zona: Chiricahiia Mts., Flagstaff, Graham Mts., Grand Canyon; Hanagan Camp (Greenlee Co.), Lakeside, McNary, Oak Creek Canyon, Prescott N. F., Vail Lake, Willians. California: Numerous localities from every county. Colorado: Estes Park, Manitou, Montrose. Idaho: Avon, Krassel. Montana: Ashland. Nebraska: Glen. Nevada: Baker, Beaver Dam St. Pk. (Lincoln Co.), Lake Tahoe. New Mexico: Albuquerque, Bandelier, Capitan Mts., Cloudcroft, Las Vegas, Lincoln N. F., Jimenez Springs, Santa Fe, Torrance Co., Ute Park. Ore- gon: Bear Springs, Lakeview. Quartz Mt. (Lake Co.), Rankin. South Dakota: Black Hills, Piedmont. Washing- ton: Blewett, Maple Valley, Mt. .'Kdams, Peshastin Creek. MEXICO: Baja California: Laguna Hansen at Sierra Juarez. Chiapas: San Cristobal. Durango: El Salto, La (^iudad, I^as Boregas. Hidalgo: Tulancingo. Gl'ATE- MALA: Cerrof:alel. Hosts.— Pinus edulis, P. monophyUa, P. jeffreyi, P. ponderosa, P. pseudostrohus; Abies concolor has been recorded, but it is not a normal host. Biology.— Usually taken from the phloem tissues of stumps and roots of the host. Evi- dently the habits are similar to other Hylastes. Notes.— The above treatment was based on types of gracilis, vastans, longus, asper. 1982 Hylastini 103 nitidus, and 296 other specimens. All defi- nitely fall within the limits of this somewhat variable species. Though a majority of the specimens from a given geographical area fit the above de- scription rather well, occasional individuals exhibit frontal characters that are rather dif- ferent in one or more respects. When ade- quate material was available these were eas- ily recognized as local variants; however, when only the extreme variants were avail- able there was some hesitation about their correct identity. 11. Hylastes porculus Erichson Fig. 46 Hylastes porculus Erichson. 1836, Archiv Naturgesch. 2:49 (Holotype, male; Pennsylvania; Berlin Zool. Mus.) Hylastes carbonarius Fitch, 1858, Noxious Insects of New York, Rpt. 4:730 (Holotype, female; Albany, New York; U.S. Nat. Mus.', 42808); LeConte, 1876, Proc. Amer. Philos. Soc. 15:389. Synonytny Hyhirgus cavcrnosus Zimmermann, 1868, Trans. Amer. Ent. Soc. 2:149 (Lectotype, male; Atlantic states; Mus. Conip. Zool., present designation); Eich- hoff, 1896, Proc. U.S. Nat. Mus. 18:606. Synonymy Hylastes granosus Chapuis, 1869, Synopsis des Scoly- tides, p. 17 (Syntypes; Southern and Middle states; Brussels Mus.); LeConte, 1876, Proc. Amer. Philos. Soc. 15:389. Synonymy Hylastes scaber Swaine, 1917, Dom. Canada Dept. .\gr- ic. Ent. Br. Tech. Bull. 14(1): 18 (Holotype, sex?; Virginia; Canadian Nat. Coll., 9326); Eggers, 1934, Ent. Nachrichtenbl. 8:25. Synonymy Hylastes swainei Eggers, 1934, Ent. Nachrichtenbl. 8:25 (Holotype, male; Frater, Ontario; U.S. Nat. Mus.); Blackman, 1941, U.S. Dept. Agric. Misc. Pub. 417:11. Synonymy Hylastes webbi Blackman, 1941, U.S. Dept. Agric. Misc. Pub. 417:10 (Holotype, female; Elmore, South Dakota; U.S. Mus., 540.33); Wood, 1971, Great Basin Nat. 31:146. Synonijmy Hylastes canadensis Blackman, 1941, U.S. Dept. .Agric. Misc. Pub. 417:15 (Holotype, female; Aweme, Manitoba; U.S. Nat. Mus.,' 54034); Wood, 1971, Great Basin Nat. 31:146. Synonymy Diagnosis.— This species is intermediate between gracilis LeConte and nigrinus (Man- nerheim). A summary of characters that dis- tinguish it from the former species is includ- ed in the above key. From nigriniis it is distinguished by the more abundant pronotal punctures, by the smoother discal interstriae, by the longer frontal carina, and by the tibial armature. Fem.\le.— Length 3.8-5.0 mm, 2.7 times as long as wide; color black. Frons as in gracilis, with interocular im- pression asually more pronounced; frontal carina acutely raised from interocular im- pression to base of epistomal lobe. Pronotum 1.1.3 times as long as wide; widest at or immediately anterior to middle, sides on basal half weakly arcuate, rather broadly rounded in front; surface ob.scurely reticulate over entire surface in material from eastern areas, at ba.sal or other margins in those from northwestern area of distribu- tion; punctures coarse, somewhat irregular in size, separated by distances one-half to equal diameter of a puncture; glabrous. Elytra 1.7 times as long as wide, 1.8 times as long as pronotum; outline as in gracilis; striae 1 weakly, others feebly or not at all im- pressed, punctures coarse, deep; interstriae narrower than striae, somewhat convex, smooth, but undulating, punctures fine, con- fused. Declivity convex, steep; basically as on disc; tubercles minute if present. Vestiture consisting of sparse, almost scalelike bristles on declivity. Male.— Similar to female except usually stouter and last visible abdominal sternum medially impressed and pubescent. Distribution.— Manitoba and New Bnmswick to Texas and Florida. CAN.\D.A: Manitoba: .Aweme, Treesbank, \\'innepeg. New Brunswick: Fredricton. Ontario: Frater, Petawawa Res., Sudbury. Quebec: Berthier, Wright. US.-K: Ala- bama: Cleborn Co., Montgomery. Arkansas: Bradley Co. Connecticut: "Ct." District of Columbia: Washington. Florida: "Fla." Georgia: Clayton, Dallas, Habersham Co., Mt. Airy, Savannah. Louisiana: Bogalusa. Maine: Orono, Paris. Maryland: Bladensburg, Glen Echo, Hyattsville, Travilah. Massachusetts: Petersham. Mich- igan: Marquette, Whitefish Point. Minnesota: Itasca Park, Whitewater St. Pk. New Hampshire: Durham, Hanover, Henniker. New Jersey: .Atlantic City, Cape May, Five Mile Beach, Lakewood, Malaga, New- foundland. New York: Jamaica (Long Island), Warrens- burg. North Carolina: .\sheville, Durham, Harnett Co., Lake Toxaway, Pink Beds, Southern Pines, Tryon. Penn- sylvania: Mt. .Alto, University Park. South Carolina: Florence, Greenville. South Dakota: Elmore. Tennessee: "Tenn." Texas: Call. Virginia: Cape Charles, Falls Church, Ft. Monroe, Gloucester Co., Mt. Vernon, Nel- son Co. West Virginia: Dellslow, Greenbriar, Hardy Co., Kaleigh Co., Randolph Co. Wisconsin: Washington Co., Wood Co. Hosts.— Presumably all species of Pinus within its range. Biology.— As in other species of the genus. 104 Great Basin Naturalist Memoirs No. 6 Notes.— The above description was based on the holotypes of porctilns (4.0 mm), cana- densis, scaber, swainei, and wehhi and on 199 other specimens. The first syntype of Hy- lastes cavernosus Zimmermann, a male pre- viously designated by a type label, is here designated as the lectotype of Zimmermann's species. In all probability the populations desig- nated here as nigrintis (Mannerheim) and as- peratus Wood intergrade with porctilus and, therefore, represent no more than subspecies. The data presently available are not ade- quate to properly determine their status. 12. Hylastes asperatus Wood Hylastes asperatus Wood, 1975, Great Basin Nat. 35:24 (Holotype, female; New Mexico; Wood Coll.) Diagnosis.— This is a difficult species to recognize. The pronotal punctures are ir- regular in size, as in porculus, but much closer; the discal interstriae are slightly wider than allied species, more nearly convex, and very finely, closely crenulate (usually not clearly apparent unless the light source is posterior to the specimen). Female.— Length 4.0-4.6 mm, 2.7 times as long as wide; color dark brown. Frons as in gracilis with interocular im- pression moderately strong, fine, low carina evidently always extending from this impres- sion to base of epistomal lobe where it forks as in related species. Pronotum 1.2 times as long as wide; sides on slightly more than basal half straight and Fig. 44. Hiflastes nigrinus: Galleries in Douglas-fir roots; A-B, maturation feeding; G-G, egg galleries. (Af- ter Zethner-Mdller and Rudinsky 1967:904.) parallel, rather broadly rounded in front; sur- face subshining, indications of reticulation obscure but usually visible at high magnifica- tion toward anterior or basal areas, punctures coarse, very close, deep, irregular in size in some specimens, interspaces usually equal to less than one-fourth diameter of a puncture; median line partly impunctate, not raised; glabrous. Elytra 1.8 times as long as wide, 1.8 times as long as pronotum; outline as in gracilis; striae moderately impressed, punctures rather coarse, deep; interstriae as wide as striae, punctures moderately coarse, close, confused, their anterior margins elevated into fine, crenulate, transverse ridges of variable height (this character approached in allied species, but not to this degree). Declivity convex, steep; striae narrowly, deeply im- pressed, punctures somewhat obscure; inter- striae about twice as wide as striae, armed by very fine, confused tubercles. Vestiture con- fined to declivity, scalelike. Male.— Similar to female except slightly stouter, and last visible abdominal sternum medially impressed and pubescent. Distribution.— Arizona and New Mexico. USA: Arizona: Hanagan Camp (Greenlee Co.), 12-VII- 68, D. E. Bright; Santa Catalina Mts., 5-VII1-68, flight, D. E. Bright. New Mexico: Alma (Carton Co.), Las Vegas, VIl-,52, 2300 m, F. H. Snow; Sierra Blanca Mt., Hopk. US7216. Hosts.— Not recorded, presumably Pinus. Biology.— Presumably this species breeds in stumps and roots of the host tree. Notes.— The type series 29 species was examined. This might possibly be a geographical race of porculus Erichson. 13. Hylastes macer LeConte Fig. 45 Ht/lastes macer LeConte, 1868, Trans. Amer. Ent. Soc. 2:175 (Lectotype, male; California; Mus. Comp. Zool., 963, present designation) Diagnosis.— Although allied to nigrinus (Mannerheim) and subopacus Blackman, this species is unique in having the entire surfaces of the pronotum and elytra finely reticulate; it is also the largest American Hylastes. Female.— Length 5.1-6.0 mm, 3.0 times as long as wide; color black. Frons essentially as in asper. 1982 Hylastini 105 Pronotum 1.3 times as long as wide; widest at middle, sides rather strongly, almost uni- formly arcuate from base to just before broadly rounded anterior margin; entire sur- face finely reticulate, punctures rather small, shallow, irregular in size and outline, inter- spaces averaging distances slightly less than diameter of a puncture; median line partly impunctate, not elevated; glabrous. Elytra 1.9 times as long as wide, 1.8 times as long as pronotum; sides almost straight and parallel on basal half, then converging slightly to a point just behind declivital base, narrowly rounded behind; striae 1 moder- ately, others feebly impressed, punctures moderately large and deep; interstriae as wide as striae, weakly convex, reticulate, sculpture slightly irregular, punctures fine, close, confused. Declivity convex, gradual above, rather steep on lower half; striae and strial punctures a little more strongly im- pressed than on disc; interstriae convex, armed by small, confused granules. Vestiture confined to declivity, scalelike. Male.— Similar to female except usually slightly stouter, and last visible abdominal sternum medially impressed and pubescent. Distribution.— British Columbia and South Dakota to California, Arizona, and Colorado. CANADA: British Columbia: Cranbrook, Creston, Kootenay N. P., Merritt (Midday Valley), Oliver. USA: Arizona: Chiricahua Mts., Flagstaff, Kaibab N. F., Wil- liams. California: Alpine, Alta Sierra (Kern Co.), Amador Co., Bass Lake, Calistoga, Camp Wolfboro (Calaveras Co.), Carmel, Carrville, Cedarville, Chester, China Camp, Colony Mill (Tulare Co.), Deer Creek (Tahama Co.), Echo Lake, Emigrant Gap, Fresno, Hamburg, Hat Creek, Hobart Mills, Huckleberry Meadow, Incline (Mariposa Co.), Kings Canyon, Lake Tahoe, La Moine, Lassen N. P., Lomo, Meadow Valley (Plumas Co.), Meyers, Miami R. S., Millwood (Fresno Co.). Modoc Co., Mt. St. Helena, Nevada City, Northfork, Pinecrest, Placer Co., Plaskett Station (Glenn Co.), Sand Flat, San Juacinto Mts., Silver Creek (Alpine Co.), Siskiyou Co., Sterling, Summerdale, Trinity Co., Woodford (Alpine Co.), Yosemite N. P. Colorado: Estes Park, Ft. Collins. Idaho: Granite, Idaho City, Krassel, Moscow, Potlatch, Robinson Lake (Latah Co.), Slate Creek R. S. (Idaho Co.), Smith's Ferry, Wallace. Montana: Columbia Falls, Helena. Nebraska: Pine Ridge. Nevada: Baker. Kyle Canyon (Clark Co.) Oregon: Anthony Lake, Beatty, Cave City, Crater Lake N. P., Deming Creek (Klamath Co.), Gardiner, Glenada, Klamath Falls, Meacham, Och- oco N. F., Pinehurst. Prineville, Tollgate. Wallowa Lake. South Dakota: Black Hills. Utah: Escalante, Brvce Canyon N. P., Zion N. P. Washington: Blewett, Buck- eye, Easton, Ft. Lewis, Glenwood, Grand Coulee, Mt. Rainier, Seattle, Skammani Co., Vaughn, Walla Walla. Hosts.— Pinus spp., less commonly from Picea engelmannii. Biology.— Galleries are constructed in phloem tissues of stumps and roots of the host tree. Notes.— The first specimen in the Le- Conte series, a male from California, has long been regarded as the type of this species; I here designate that specimen as the lectotype of macer. The lectotype and 682 other speci- mens were examined. 14. Hylastes nigrinus (Mannerheim) Figs. 18, 19, 20, 45, 46 Hijlurgus nigrinus Mannerheim, 1852, Bull. Soc. Imp. Sci. Nat. Moscou 25:.356 (Holotype, female; Sitka Island, Alaska; Helsinki Mus.) Hylastes nigrinus: LeConte, 1868, Trans Amer. Ent. Soc. 2:174 Hylastes yukonis Fall, 1926, Pan-Pacific Ent. 2:207 (Holotype, male; White Horse, Yukon Territory; Mus. Comp. Zool.); Wood, 1957, Canadian Ent. 89: 396. Synonymy Fig. 45. Hylastes macer: Lateral aspect, (.-^fter Bright 1976:206.) 106 Great Basin Naturalist Memoirs No. 6 Diagnosis.— This species is very closely related to porciilus. The differences are ob- sciire and characters may intergrade when additional material becomes available. This species has the pronotal punctures slightly smaller and more closely placed, and the punctures on the declivital striae are smaller. Because nigrinus, asperatus, and porculus re- place one another geographically, it is entire- ly possible that they are only subspecies of one another. Additional material from inter- mediate localities must be examined before their status can be clarified. Female.— Length 3.8-4.9 mm, 2.7 times as long as wide; color black. Frons as in porculus. Pronotum 1.13 times as long as wide; widest at or just behind middle, sides rather weakly arcuate from base, rather broadly rounded in front; surface smooth and shining, usually with areas of obscure reticulation at base or other marginal areas, punctures rather coarse, deep, close, interspaces almost always equal to less than half diameter of a puncture; median line largely impunctate; glabrous. Elytra 1.8 times as long as wide, 1.9 times as long as pronotum; outline as in proculus; striae feebly impressed, punctures coarse, deep; interstriae as wide as striae, weakly convex, surface irregular (undulating), smooth, shining, punctures small, close, con- fused. Declivity as in porculus except striae usually slightly narrower and deeper than in- terstriae (striae slightly wider than interstriae in porculus). Vestiture largely confined to de- clivity, consisting of interstrial scales as in re- lated species. Male.— Similar to female except usually slightly stouter, and last visible abdominal sternum medially impressed and pubescent. Distribution.— Alaska and California to W Montana. Fig. 46. Hylastes spp., distribution map: nigrinus, .solid circles; subopacus, solid squares; porculus, open circles. 1982 Hylastini 107 ALASKA: Sitka Island. CANADA: Alberta: La^gan." British Columbia: Atlin, Bear Lake, Bowser, Kokaiiee Mt., Lorna. Luinberton, Merritt (Midday Valley), Nel- son, North Bend, Pender Harbor, Port Renfrew, Sidney, Sinnmerland, Victoria. Northwest Territories: Ft. Smith. Yukon: White Horse. US.\: California: Ben Lomond, Che.ster, Fieldbrook, Ft. Seward, Happy Camp (Siskiyou Co.), Hat Creek, Lasjimitas, Lamoine (Shasta Co.), Los Angeles, Los Catos, Meadow Valley (Plumas Co.), McCloud, Mill Valley, Mt. St. Helena, Quincy, San Mateo Co., Santa Rosa, Sequoia N. P., Shasta N. F., Summit Road (Santa Cruz Co.). Idaho: Coeur d'Alene, Harvard (Latah Co.), Priest River, St. Maries (Benewah Co.). Montana: Lindburg Lake at Condon. Oregon: Amity, Astoria, Baker Creek, Bear Springs R. S., Cannon Beach, Clackamas Co., Clatsop Co., Clear Lake, Cor- vallis, Dayton, Detroit, Eugene, Forest Grove, Gardiner, Golden, Griffin Creek (Jackson Co.), Hillsboro, Hood River, Keno, Klamath Falls, Lane Co., Manzanita, Mary's Peak, McMinnville, Medford, Mosier, Mt. Hood, Neotsu, Newberg, Pacific City, Paradise Park, Portland, Sand Lake, Silver Creek Falls, Sisters, St. Helens, Scap- poose. Sweet Basin, Tillamook, Trail, Veronia, Wald- port. Wending, Winenia N. F., Yamhill Co. Washing- ton: .\merican Lake, Beaver, Bothel, Chase Lake (Snohomish Co.), Cranberry Creek (Mason Co.), Eaton- ville, Elva, Everett, Glenwood, Green River Gorge, Lewis and Clark St. Pk., Lester, Moclips, Mt. Adams, Mt. Baker, Mt. Rainier, Ocean Park, Olympia, Olympic N. P., Parkland, Port Blakely, Puyallup, Quillayute, Quinault, Seattle, Sequim Bay St. Pk., Sk"ye, Sol Duk Sp.. Tacoma, Vantage, Vaughn, Wending, Winslow. Hosts.— The species of Pinus, Picea, Pseu- dotsuga, Tsuga, Larix, and Abies in approx- imately that order of preference. Biology.— This common species infests the phloem tissues of stumps and roots of the ho.st trees. The biramous adult galleries score the wood very lightly; evidently they most commonly run transverse to the grain of the wood. The larval mines appear to wander aimlessly through the phloem tissues. Notes.— The types of nigrintis and ijuk- onis and 675 other specimens were examined. There are some minor geographical varia- tions in the population, but none of these ex- hibit trends toward those found in the geo- graphical replacement species porciihis in the eastern United States and asperatus in the southern Rocky Mountains. Until some in- dication of intergradation is found it appears best to retain these forms as valid species. 15. Hykistes subopacus Blackman Fig. 46 Hylastes subopacus Blackman, 194L U.S. Dept. .Agric. Misc. Pub. 417:9 (Holotype, male; Capitan Mountains, New Mexico; U.S. Nat. Mus., 540.32) Diagnosis.— This species is very closely related to nigrinu.s and replaces that species geographically in Utah, Colorado, and New Mexico. Its size, habits and structure suggest that it is a distinct species, not a geographical race. It is distinguished by characters summa- rized in the above key. Female.— Length 4.4-5.5 mm, 2.6 times as long as wide; color black. Frons as in nigrintis except inflated area on lower half more poorly developed, epistomal impression somewhat more extensive. Pronotum 1.1 times as long as wide; sides almost straight and parallel on basal half, then arcuately converging to broadly rounded anterior margin; surface minutely, obscurely reticulate, punctures moderately small, rather deep, close, interspaces equal to less than half diameter of a puncture; middle half of median line impunctate; glabrous. Elytra 1.6 times as long as wide, 1.8 times as long as pronotum; outline .similar to ni- grinus; striae feebly impressed anteriorly, stronger behind, punctures rather coarse, deep; interstriae slightly wider than striae, punctures sm.all, confused, finely subasperate. Declivity as in nigrinus, striae slightly more strongly impressed, punctures small; inter- strial tubercles usually smaller. Male.— Similar to female except slightly stouter, and last visible abdominal sternum medially impressed and pubescent. Distribution.— Utah and Wyoming to New Mexico. US.\: Colorado: .Argentine Road; Silverton, VIII-85. New Mexico: Capitan Mts., IT-VH-OT, J. L. Webb. Utah: Brighton, VH-IS, Hubbard and Schwarz; Logan Canyon, 6-VII-48, and 18-VI-49, Abies lask>car}ni. S. L. Wood; Wolf Creek Pass, 17-VI-60, Abies hisiocdrpa, S. L. Wood. Wyoming: Brooks Lake; Medicine Bow Range 1929, .3200 m'. Host.— Abies lasiocarpa. Biology.— Tunnels were constructed in phloem tissues of stumps and roots of large, dying, standing trees. The biramous parental tunnels tended to be transverse and scarcely engraved the wood. Larval mines u.sually were exposed on peeled bark and appeared to wander at random. Both larvae and adults were present on the three occasions when ob- servations were made. Notes.— The male holotype, both male paratypes, and 19 other specimens were ex- amined for this studv. Tribe HYLESININI Hylesi.nen Erichson, 1836, Archiv Naturgesth. 2:46 (Type-genus: Hylesinus Fabricius, 1801) Phloeotrupidae Chapuis, 1866, in: Lacordaire, Hist. Nat. Insectes, Coleopt. 7:.357 (Type-genus: Phloeotrupes Erich- son, 1836) Phloeobori Blandford, 1893, Trans. Ent. Soc. London 1893:426 (Type-genus: Phloeohorus Erichson, 18.36) Dactylop.\lpi Blandford, 1893, Trans. Ent. Soc. London 1893:426 (Type-genus: Dactylopalpus Chapuis, 1869) Hylastinides Niisslin, 1912, Naturwiss. Zeitschr. Forst- und Landwirtschaft 1912:273 (Type-genus; Hylastinus Bed- el, 1888) Alniphagini Murayania, 1963, Studies in the scolytid fauna of the northern half of the Far East, V, Hylesininae, p. 29 (Type-genus: Alniphagus Swaine, 1918) Anatomical features.— The frons is ob- scurely to moderately sexually dimorphic, the eye is entire to feebly sinuate on the anterior margin, the antennal funicle is 6- or 7-seg- mented, the club is symmetrical and conical to moderately flattened, with the sutures in- dicated, the procoxae are contiguous to rather narrowly separated, the pronotum is armed by a few asperities (except in Hylas- tinus), the metascutellar area is separated from the postnotum by a distinct suture, and the sutural groove on the mesal surface at the base of the elytra is interrupted by a series of interlocking nodules and cavities. Biological features.— All species are monogamous, all American species except Phloeohorus are phloeophagous. Their paren- tal tunnels are either biramous or, if mono- ramous, there is a well-developed turning niche near the entrance tunnel. Eggs are de- posited in niches. Larval mines usually follow a definite course away from the parental gal- lery and rarely cross one another. Phloeo- horus is xylophagous and appears to have a symbiotic relationship with fimgi, although not in a mycetophagous sense. Taxonomy.— This tribe is somewhat inter- mediate between the Hylastini and Tomicini. Of the three native genera, two appear to have been derived from Eurasia {Alniphagus and Hylesinus) and one from South America (Phloeohorus). Most of the genera in this tribe occur in the Old World. The American gen- era of Hylesinini are easily recognized; those from other parts of the world may be distin- guished with great difficulty. Genus HYLASTINUS Bedel Hylastinus Bedel, 1888, Ann. Soc. Ent. France, Hors Ser. 6:388 (Type-species: Ips obscurus Marsham, monobasic) Diagnosis.— This genus is not closely al- lied to other American genera. It is easily dis- tinguished by characters summarized in the above key to genera and in the diagnosis of ohscurus below. Description.— Length 2.0-2.5 mm, 2.2 times as long as wide; color dark brown. Frons as described below for ohscurus; eye entire, elongate; antennal scape elongate, fu- nicle 7-segmented club with three sutures, 1 and 2 septate. Scutellum small, slightly de- pressed; bases of elytra armed by a single row of overlapping crenulations extending to striae 9. Declivity convex, steep; sculpture conservative. Vestiture hairlike. Prothoracic intercoxal piece moderately wide, margined laterally in front of coxae by an acutely ele- vated ridge extending from coxa to anterior margin. Third tarsal segments bilobed. Distribution.— Four European species are known, one of which has been introduced into North America. Biology.— The adults bore in the roots of leguminous hosts, where they rear their broods. Hylastinus ohscurus (Marsham) Ips ohscurtis Marsham, 1803, Entomologia Britanica, p. 57 (Syntypes?; Type locality unknown, probably England; not located) Hylastes ohscurus: C'hapnian, 1869, Ent. Mon. Mag. 6:6. Synonymy 108 1982 Hylesinini 109 Hylastinus ohsctirus. Bedel, 1888, Ann. Soc. Ent. France, Hors. Ser. 6:388. Synonymy Dennestes trifolii Miiller, 180.3, Mem. Soc. Sci. Dep. du Mont. Tonerre 1:47 (Syntypes?; Central Europe; not located); Chapman, 1869, Ent. Mon. Mag. 6:6. Synonymy Hylesinus crenulatus Duftschmid, 1825, Fauna Austri- aca 3:104 (Syntypes?; Linz, Austria; depository not located); Hagedorn, 1910, Coleopt. Cat. 4:12. Synonymy Hylurgus picctis Stephens, 18.30, Illustrations of British Entomology 3:365 (Syntypes; London, England; British Mus. Nat. Hist.); Hagedorn, 1910, Coleopt. Cat. 4:12. Synonymy Hyhirgus fttscescens Stephens, 1830, Illustrations of British Entomology 3:365 (Syntypes?; London, England; British Mus. Nat. Hist.); Hagedorn, 1910, Coleopt. Cat. 4:12. Synonymy Hylastinus kroaticus Fuchs, 1912, Morphologische Studi- en uber Borkenkafer. II. Die europaischen Hy- lesinen, p. .39 (Syntypes?; Warasdin, Croatia; not known to me); Schedl, 1964, Riechenbachia 2:210 (Synonymy; as croaticus) Hylastinus pilosus Eggers, 1944, Ent. Blatt. 40:140 (Holotype, male?; .\lgiers; U.S. Nat. Mus., 59131); Schedl, 1960, Ent. Mitt. 31:162. Synonymy Diagnosis.— This species, introduced from Europe, is not closely related to any native American species, although it superficially resembles Hylurgopinus rufipes (Eichhoff), with which it commonly is confused in col- lections. It is most easily distinguished from rufipes by the presence of a strongly elevated ridge extending from the lateral margin of the fore coxae to the anterior margin of the pronotum; it also has a conspicuous, trans- verse, interocular impression and it com- pletely lacks a sharply defined premandibular epistomal lobe. Female.— Length 2.0-2.5 mm, 2.2 times as long as wide; color dark brown. Frons convex, with a rather well-devel- oped, transverse, interocular impression then slightly inflated to level of antennal insertion, transversely impressed just above epistomal margin, epistomal lobe rather well devel- oped; surface coarsely reticulate, with coarse, close, very shallow obscure punctures; vesti- ture hairlike, short, inconspicuous. Pronotum 0.9 times as long as wide; widest about one-third length from base, sides rather strongly arcuate on basal two-thirds, rather shallowly constricted just before broadly roimded anterior margin; surface coarsely, deeply, closely punctured, fundus of most pimctures obscurely reticulate, interspaces very narrow, shining; vestiture hairlike, mod- erately long, rather abundant. Elytra 1.4 times as long as wide, 1.9 times as long as pronotum; sides almost straight and parallel on basal two-thirds to declivital base, rather broadly rounded behind; ba.sal margin of each elytron armed by a single row of moderately large, overlapping crenulations extending to base of striae 9; striae weakly impressed, punctures large, deep; interstriae distinctly narrower than striae, feebly con- vex, punctures rather fine, part of them sub- crenulate, becoming tuberculate toward de- clivity. Declivity convex, rather steep; striae slightly narrower, interstriae more strongly convex than on disc; each interstriae armed by a row of rather fine, pointed tubercles. Vestiture consisting of coarse, hairlike, inter- strial setae about equal in length to diameter of a strial puncture, and median rows of in- terstrial hair about twice as long as more abundant ground vestiture. Male.— Apparently distinguished from fe- male only by differences in terminal abdomi- nal terga. Distribution.— North Africa, south and central Europe to the Caucasus, British Co- lumbia and Ontario to California and Georgia. CANADA; British Columbia: Bear Hill, Grindrod, Sidney. Ontario: Prince Edward Co., Toronto, Trenton. USA: California: Neyada City. Connecticut: Stamford. Georgia: Waddington. Idaho: Boise, Caldwell, Chilco, Council, Hubbs Butte, Moscow, Murtaugh, Parma, Weippe, Wilder. Indiana: Bern, Ft. Wayne, LaFayette, Oakville, Wabash Co. Maryland: Hagerstown. Mas- sachusetts: Forest Hills. Michigan: .Agricultural College, Washtenaw. New^ Hampshire; Durham. New Jersey: Greenwood Lake, Hackettstown. Hohokus, Iryington. New York: Bridgeport, Dundee, Elmyra, Ithaca, Meck- lensburg, Newport, Onondaga Co., West Point. Ohio: Columbus, Delaware Co., Hartsgrove, Holgate, Lorain Co., Rock Creek, Scotio Co., Westville. Oregon: Beth- any, Canby, Cornelius, Corvallis, Dayton, Deyer, Forest Grove, Marshfield, McMinnville, Molalla, Portland, Ridgeway, Roseburg, Salem, Scio, Sheridan. Scappoose, St. Helens, Taft. Utah: Benson, Garden City, Honeyyille, Spring Lake in LUah Co., Tremonton. Washington: Blaine, Bothell, Cedar Mt., Chase Lake, Conway, Du- yall, Evans Creek (King Co.), Gardiner, Loveland, Man- chester, Mt. Vernon, Port Townsend, Pullman, Renton, Sutton, Vancouver. Hosts.— Trifolium spp. preferred, al- though Medicago, Melilotus, Lathynts, and Vicia species are acceptable. Biology.— Overwinters as voung adults or larvae in infested clover roots in the ground. New adult tunnels are constructed in the spring in unthriftv plants. The galleries are 110 Great Basin Naturalist Memoirs No. 6 basically of the biramous type with eggs de- posited in niches along the margins. The lar- vae mine at random through the root tissues. Pupation occurs during late summer. There is one generation each year. Notes.— The above treatment was based on 216 American specimens that were com- pared to several European specimens identi- fied by Eichhoff, Eggers, etc. Genus HYLESINUS Fabricius Hylesimis Fabricius, 1801, Syst. Eleuth. 2:39() (Type- species: Hylesinus crenatiis Fabricius, subsequent designation by Westwood, 1838, Synopsis of the genera of British Insects, p. 39) Ficicis Lea, 1910, Proc. Roy. Soc. Victoria, n. s., 22:147 (Tvpe-species: Ficicis various Lea, subsequent designation by Hopkins, 1914, Proc. U.S. Nat. Mus. 48:122); Schedl, 1936, Proc. S. AustraHa Mus. 5:521. Synonymij Leperisinus Reitter, 1913, Wiener Ent. Zeit. 32(Bei- heft):41 (Type-species: Bostrichus fraxini Panzer = B. varius Fabricius, subsequent designation by Swaine, 1918, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(2):70); Wood, 1978. Great Ba- sin Nat. 37:511. Synonymy Ficiphagtts Murayama, 1958, Yamaguti Univ. Facul. Agric. Bull. 9:930 (Type-species: Ficiphagus goliathoides Murayama = Hylesinus porcatus Chapuis, original designation); Schedl, 1962, Beitr. Ent. 12:486. Synonymy Diagnosis.— American species are easily distinguished by the scalelike vestiture and the moderately ascending abdomen. Alni- phagus is the most closely allied American genus. Description.— Length 1.8-4.0 mm, 1.8-2.0 times as long as wide; color dark brown, densely clothed by various mixtures of white, tan, brown, or black scales to form characteristic color patterns; frons in male tran.sversely impressed to strongly concave, devoid of median carina, female frons flat- tened to convex, a median carina often pres- ent. Eye oval, anterior margin weakly sin- uate. Antennal scape elongate; funicle 7- segmented; club elongate, slightly flattened, slightly asymmetrical, marked by three asep- tate sutures. Pronotum wider than long, ante- rolateral areas usually armed by several cre- nulations. Scutellum rather small, round. Elytral bases armed by a long row of closely set, overlapping crenulations; striate; declivi- ty convex, moderately steep, abdomen as- cending almost halfway to meet apex of elytra. Vestiture largely scalelike. Distribution.— North America to Guate- mala; Europe and Asia to Australia; eight species occur in America, about 30 species in the Eastern hemisphere. Biology.— The monogamous species cut transverse biramous egg galleries that en- grave the wood rather deeply. The larvae mine primarily in the phloem tissues parallel to the grain of the wood. With few excep- tions the host plants belong to the genus Fra- xinus. The winter is passed in the adult stage outside of the brood gallery system in indi- vidual feeding and hibernation tunnels con- structed in green bark of living trees. Black- man (1922a:63) estimated that as many as three generations may occur in one season. Notes.— The genus Hylesinus Fabricius has been rather seriously abused in taxonomic literature, primarily because of the extreme diversity of species presently included in it and in several genera closely allied to it. An obvious need for a complete reevaluation of these genera exists. Key to the Species of Hylesinus 1. Male frons transversely impressed on less than lower half, moderately convex above; setae on propleural area rather slender, usually simple, almost never di- vided into more than two parts; setae on abdominal sternum 5 long and slender, essentially hairlike 2 — Male frons concavely excavated from epistoma to upper level of eyes; setae on propleural area broad, usually divided into three or more filaments; setae on abdominal .sternum 5 stout, largely scalelike (hairlike in califomicus and guatemalensis) 4 2(1). Pronotum devoid of asperities in anterior or anterolateral areas; frontal vesti- ture very .short; North Dakota and Ontario to Vermont and Tennessee; 3.2-4.0 mm 1. pruinosus Eichhoff 1982 Hylesinini 111 — Pronotum armed by several coarse asperities in anterolateral areas, usually supplemented by a row of small submarginal ones in anteromedian area; frontal pubescence moderately long; smaller species 3 3(2). Frons with fine, shallow punctures in both sexes, male entirely devoid of a me- dian carina; discal interstrial crenulations rather fine; discal scales on elytra smaller, averaging one-fourth as wide as interstriae; South Dakota and Kansas to Quebec and New Jersey; 2.0-3.0 mm 2. aculeatus Say — Frons with coarse, moderately deep punctures in both sexes, lower half of male frons with a low, poorly developed, median carina; discal crenulations much larger; discal scales on elytra larger, averaging one-third as wide as interstriae; Oregon to California; 2.5-3.3 mm 3. oregonus (Blackman) 4(1). Smaller; declivital interstriae 2 as wide as 1 or 3, not conspicuously depressed, armed on upper half by a few small granules; median line on female frons weakly impressed; median row of scales on each interstriae not longer, usually not erect anywhere on elytra; Saskatchewan and Colorado to Ontario; 1.9-2.4 mm 4. criddlei (Swaine) — Larger; declivital interstriae 2 much narrower than 1 or 3, or strongly im- pressed or both, devoid of granules; female frons carinate (except guatema- lensis); median row of scales (or hair) on some interstriae erect and conspicuously longer than ground cover 5 5(4). Scales on mature specimens black and white with a few tan; female frontal ca- rina acute, more than half as long as frons; interstriae 9 and 10 with vestiture scalelike, none noticeably longer than ground cover; declivital interstriae 2 narrowly convex, bearing one row of scales at middle of declivity 6 — Scales on mature specimens brown and tan or white; female frons if carinate, carina very short, subtuberculate, confined to lower half; interstriae 9 and 10 with some slender setae at least twice as long as ground scales; declivital inter- striae 2 impressed (slightly convex in some females) bearing at least two staggered ranks of scales 7 6(5). Smaller; scales on basal half of interstriae 9 and 10 more slender, mostly two to four times as long as wide; scales on erect median row of each interstriae only slightly longer than ground cover; black scales usually cover at least 70 percent of elytral surface; Pennsylvania and New Jersey to Missouri; 1.8-2.3 mm 5. fasciatus LeConte — Larger; scales on basal half of interstriae 9 and 10 almost as broad as those in other areas, usually less than twice as long as wide; scales on erect median row of each interstriae conspicuously longer than ground cover; black scales usually cover less than 50 percent of elytral surface; SW Texas and Durango to Puebla; 2.3-2.9 mm 6. mexicanus (Wood) 7(5). Male frons much less strongly concave, female frons more distinctly impressed but not concave, a median carina present on lower half in both .sexes; erect in- terstrial setae on declivity more widely spaced, slender, about four to eight times as long as wide, setae in ground cover on 1-3 similar, erect setae never present on 2; Mexico; Fraxinus uhdei; 3.8-4.2 mm 7. aztecus Wood — Male frons more strongly concave, never with a median carina, female more distinctly convex, a carina present or not; erect interstrial setae on declivity on 1 and 3 very close, very broad, each about one to four times as long as wide, some erect setae always present on 2 in female (rare in male) 8 112 Great Basin Naturalist Memoirs No. 6 8(7). Female frons with a short, rounded, prominent carina just below middle; male frons more narrowly, not uniformly concave; elytral scales in ground cover much larger, about one-third as wide as interstriae; Oregon and North Dakota to Chihuahua and Texas; 2.0-3.1 mm 8. californicus (Swaine) — Female frons flat, entirely devoid of a median carina; male frons broadly, uni- formly concave; elytral scales in ground cover much smaller, about one-fifth as wide as interstriae; Guatemala; 2.4-3.1 mm 9. guatemalensis (Wood) 1. Hylesinus pruinosus Eichhoff Hiflesinus pruinosus Eichhoff, 1868, Berliner Ent. Zeitschr. 12:149 (Syntypes ?; Anierique Boreale; lost with Hamburg Miis.) Diagnosis.— This species is very closely al- lied to oculeatus Say, but it may be distin- guished by the larger size, by the coarser frontal pimctures, by the absence of pronotal asperities, and by the very coarse, uniseriate, interstrial crenulations that are consistently as tall as neighboring scales. Male.— Length 3.2-4.0 mm, 2.0 times as long as wide; color very dark brown, with a variegated pattern of light and dark scales. Frons as in aculeatus except slightly more convex and punctures distinctly larger. Pro- notum as in aculeatus except asperities in an- terolateral areas small to obsolete. Elytra as in aculeatus. Female.— Similar to male aculeatus ex- cept differing by characters noted above for male. Distribution.— North Dakota, Ontario, and Vermont to Tennessee and Virginia. CANADA: Ontario: "Ontario"; Ridgeway. USA; Il- linois: Urhana, 26-IV-08; Webster; "N. 111." Indiana: Co- lumbus, 26-1X-20. Kentucky: Lexington, 4-VII1-58. Michigan: Detroit. Missouri: St. Louis. New Hampshire: Webster. New York: Bear Mountain, 13-VII1-48; Buf- falo; Ellenville, VIII-41, Fraxinus; Ithaca. North Caro- lina: Trvon. Hopk. US 2621a, 3631a, 3656a. North Da- kota: Richland Co., 27-V-71, W. J. Brandvik. Pennsylvania: "N. Cumberland"; "Pa." Tennessee: "Tenn." Vermont: Ilighgate. Virginia: "Va, V-30." Hosts.— Fraxinus. Notes.— The above treatment was based on 30 specimens. Their identity was based on specimens determined by Blackman, Schwarz, and Swaine and on the original description. This species evidently is rare and poorly represented in collections. It is very similar to some of the variants on the northwestern margins of the distribution of aculeatus and it is not at all impossible that it could be noth- ing more than an extreme morphological var- iant of aculeatus. Additional specimens and field notes are necessary to clarify its tax- onomic status. 2. Hylesinus aculeatus Say Hylesinus aculeatus Say, 1824, J. Acad. Nat. Sci. Phila- delphia 3:322 (Syntypes?; Missouri; evidently lost) Hylesinus iniperialis Eichhoff, 1868, Berliner Ent. Zeitschr. 12:149 (Syntypes; Wisconsin and Georgia; lo.st with Hamburg Mus.); Wood, 1973, Great Basin Nat. 33: 178. Synornjiny Lesperisinus cinereus Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1): 15 (Lectotype, female; Hudson, Quebec; Canadian Nat. Coll., designated by Bright, 1967, Canadian Ent. 99:676); Wood, 1957, Canadian Ent. 89:399. Synonymy Diagnosis.— This common, variable, wide- ly distributed eastern species is allied to vari- us (Fabricius), of Europe, to the American pruinosus Eichhoff, and to oregonus (Black- man). From the two latter species it is distin- guished by characters summarized in the above key. From the former it is easily distin- guished by the smaller size, by the lighter color, and by the different frontal sculpture in both sexes. Male.— Length 2.0-3.0 mm, 1.9 times as long as wide; color dark brown, with a varie- gated pattern of light and dark scales. Frons flattened from just below upper lev- el of eyes to just above epistoma, then gradu- ally ascending to epistomal margin, lateral margins weakly elevated on lower third; sur- face reticulate, almost reticulate-granulate, finely punctured; a very feeble, median ca- rina on lower half; vestiture of coarse, mod- erately abundant hair of moderate length over entire surface. Pronotum 0.72 times as long as wide; widest at base, sides arcuately converging to distinct lateral constriction immediately be- hind broadly rounded anterior margin; crenu- lations in anterolateral areas moderately large, rarely reduced, a low, submarginal row u.sually extending to median line; surface minutely reticulate-granulate, punctures moderately large, close, somewhat obscure; 1982 Hylesinini 113 median line indicated one-third pronotum length from base; closely covered by non- overlapping scales, each scale subcircular at base, subtriangular in anterior area; dark scales form diamond pattern on median third from anterior to posterior margins, lateral margins also dark. Elytra 1.4 times as long as wide, 2.1 times as long as pronotum; sides very feebly ar- cuate, subparallel on slightly less than basal two-thirds, rather broadly rounded behind; basal margins, each armed by about 15 cren- ulations, striae narrowly impressed, punc- tures rather obscure; interstriae twice as wide as striae, base of 2 armed by about a dozen submarginal crenulations, 3 by about 6, 4 by about 3, and 5 by about 2 submarginal crenu- lations; interstriae each armed by a moder- ately confused row of narrow, low crenula- tions, each shorter than length of a scale, general surface obscured by scales. Declivity moderately steep, convex; interstriae 2 im- pressed but still convex, tubercles on 3 and 9 slightly larger than on disc, 1, 3, 7, and 9 usu- ally appearing slightly elevated. Vestiture scalelike, scales as wide as long, about one- fourth as wide as an interstriae, most of those near and on declivity with an elevated me- dian crest; a median row of scales on inter- striae 1 and 3 often erect and very slightly longer (less than 1.5 times) than ground cov- er; light scales in patches, usually comprising 50 to 60 percent of total, occasionally dark scales entirely absent. Female.— Similar to male except frons weakly convex, obscure median carina long- er; pronotal crenulations usually larger and more numerous. Distribution.— South Dakota and Quebec to eastern Kansas and North Carolina. CANADA: Manitoba: Aweme, Dauphin, Morden, Winnipeg. Nova Scotia: Lawrencetown. Ontario: Chalk River, Ottawa, Petawavva Res., Prince Edward Co. Que- bec: Ayhiier, Hemmingford, Isle Perrot, Lake Memph- reinagog, Ste. .\nne de Bellevue, St. Hilaire. USA: Ar- kansas: Blythville. Colorado: Fort Collins. Connecticut: Bethlehem, Chaplin, Cornwall, Stamford. District of Co- lumbia: Washington. Illinois: Chicago, Macomb. In- diana: "Indiana." Iowa: .\mes, Iowa City. Kansas: Ft. Scott, Norton, Partridge, Riley Co., Salina, Topeka. Louisiana: Frenier, New Orleans, Tallulah. Maine: Lovel, Paris, South Hope, Orono, Wales, Yarmouth. Maryland: Plummers Island. Massachusetts: Charle- mont, Commington, Framingham, Hopedale, Lawrence, Petersham, Stoughton, Westborg. Michigan: Detroit, East Lansing, Pittsfield Twp. in \\'ashtesaw Co. Minnesota: Buffalo State Park. Mississippi: Agricultural College. Nebraska: Broken Bow, Omaha. New Hamp- shire: Durham, Webster. New Jersey: Boonton, Clcmon- ton, Glen Gardner, Orange Mts., Peterson, South Moun- tain. New York: Buffalo, Cheektown, EUenville, Ithaca, Ogdeiisbiirg, Patchin, Scarsdale, Syracuse, Utica, West Point. North Carolina: Tryon. North Dakota: Botteneau, Cass Co., Fargo, Regent, Richland Co., Roosevelt N. P. Ohio: Bowling Green, Clinton Co., Columbus, Franklin Co., Tiffin. Oklahoma: Payne Co. Pennsylvania: Castle Rock, Clarks Valley, Easton, Harrisburg, Milford, North Cumberland, Pecks Pond, Philadelphia, Philmont, Swarthmore, Wyoming. South Carolina: Batesburg, Clemson, Ferguson. South Dakota: McHenry Co. Ten- nessee: Memphis. Texas: Dallas. Virginia: Falls Church. West Virginia: Kanawah Station, Monongalia, Randolph Co. Hosts.— Fraxinus americana and F. spp. Biology.— The bole, limbs, and larger branches are selected for attack where trans- verse, biramous, parental galleries deeply en- grave the surface of the wood. According to Blackman (1922a:62) the transverse length of the complete gallery systems he studied in Mississippi varied from 2 to 6 cm and aver- aged 4 cm. The larval mines follow the grain of the wood and normally do not cross one another. The young adults do little if any feeding before they emerge from the brood host. Evidently feeding tunnels in green bark are not formed between succeeding summer generations, but they are formed by over- wintering beetles. About two months were required to complete a generation in Mississippi. Notes.— The above descriptions were based on LeConte's series of aculeatus, which was either part of Say's series or compared to it; on LeConte's series of imperiolis, which apparently included an Eichhoff specimen; on the type series of cinereus Swaine; on the Schwarz, Hopkins, and Blackman series of aculeatus; and on more than 700 other speci- mens. A specimen labeled "N.Y.; Cornell Lot. 3 Sub. 5; Hylesinus imperialis Lee. homo- type" (the identification label is in Swaine's hand) is a female of califomicus and does not match either of LeConte's series. Because the types of both aculeatus and imperalis appar- ently were lost, LeConte's specimens appear to be the only existing specimens that were either part of the type series or compared to the types of the Say and Eichhoff descriptions. 114 Great Basin Naturalist Memoirs No. 6 3. Hylesinus oregonus (Blackman) Leperisinus oregonus Blackman, 1943, Proc. U.S. Nat. Mus. 94:396 (Holotvpe, female; Forest Grove, Oregon; U.S. Nat. Nliis., .56574) Diagnosis.— This species is closely related to aculeatus Say, but it may be distinguished by characters summarized in the above key. Male.— Length 2.5-3.3 mm, 2.0 times as long as wide; color dark brown, with a varie- gated pattern of dark brown, yellow, and pale scales, dark scales predominating. Frons as in aculeatus except carina very slightly higher, punctures much larger and deeper, and vestiture finer. Pronotum 0.73 times as long as wide; as in aculeatus except submarginal row of crenula- tions usually not complete to median line, surface more coarsely, deeply punctured, and scales larger. Elytra 1.5 times as long as wide, 2.1 times as long as pronotum; as in aculeatus except striae very slightly wider, interstrial crenula- tions averaging slightly less numberous and higher, scales larger, wider, each scale a third as wide as an interstriae, fewer of them strongly keeled; dark brown scales comprise about half of total, yellow and pale scales about equally abundant. Female.— Similar to male except frons convex on upper three-fourths, carina slightly longer and higher. Distribution.— Oregon to California. USA: California: Hilts, 18-IV-.33, .\sh, Paul Rice. Ore- gon: Corvallis, 24-IV'-3I, 6-X-31, 15-VII-41, Fraxinus ore- ganci, J. Scliuh; Eugene; Forest Grove, 18-1-19, Fraxinus: McMinnville; Philomath; McLane; Portland, 26-VII, C. E. Wood, 14-VIII-.34, F. oregona, F. P. Keen; St. Helens, Hopk. US117, Fraxinus, A. D. Hopkins; Scappoose. Host.— Fraxinus latifolia. Biology.— Evidently indistinguishable from aculeatus. Notes.— The above descriptions were based on the holotype and on 153 other spec- imens. This appears to be a rare species; its distribution along the Pacific Coast probably is much greater than available records indicate. 4. Hylesinus criddlei (Swaine) Leperisinus criddlei Swaine, 1918, Dom. Ganada Dept. Agric. Ent. Br. Tech. Bull. 14(2): 72 (Holotype, male; Awenie, Manitoba; Canadian Nat. Coll., 9251) Diagnosis.— This is the most di.stinctive and also the most difficult American species of the genus to characterize. Its small size, the comparatively .simple sculpture of the elytral declivity, and the presence of a weak, median, frontal impression, rather than an elevation, serve to distinguish it. Male.— Length 1.9-2.4 mm, 2.0 times as long as wide; color dark brown, with a varie- gated pattern of dark brown, yellowish tan, and pale scales, pale scales usually predominate. Frons rather abruptly, concavely im- pressed above epistoma, impression extend- ing to upper level of eyes at least in median area, lateral margins subacutely elevated on lower third; surface minutely reticulate; ves- titure consisting of moderately abundant, coarse, rather long, subplumose setae. Pronotum 0.71 times as long as wide; widest on basal third, sides rather weakly ar- cuate and converging slightly on basal half, then abruptly rounded and converging to moderate constriction just before broadly rounded, subemarginate anterior margin; sur- face reticulate, obscurely punctured, with several coarse asperities in anterolateral area, a marginal row of asperities extending almost to median line on anterior margin; scales usu- ally not overlapping, rather large, broad over most of surface, narrower in front, color pat- tern as in aculeatus. Elytra 1.5 times as long as wide, 2.1 times as long as pronotum; outline as in aculeatus; disc as in aculeatus except submarginal cre- nulations smaller, interstrial crenulations nar- rower, more nearly uniseriate. Declivity con- vex, moderately steep; interstriae 1, 3, and 9 weakly elevated, 2 almost flat, as wide as 1 or 3 and bearing four indefinite ranks of scales. Vestiture consisting of overlapping interstrial scales, each scale as wide as long, almost a third as wide as interstriae; an occasional .scale on declivity erect and slightly longer than ground vestiture; light scales usually predominate, tan scales least abundant. Female.— Similar to male except frons convex on upper three-fourths, median line weakly impressed; asperities on pronotum slightly larger. Distribution.— Saskatchewan and Colo- rado to Quebec. 1982 Hylesinini 115 CANADA: Manitoba: Aweme, 31-VII-15, Ex. No. 8178, N. Griddle. Ontario: Port Colborne, 1-VIII-.34, D. Grav; Ridgewav, \. H. Kilman. Quebec: Cap Rouge, 15- V-7i; Gaspe, 25-VI-.37. C. Gautier; Montreal, 12-VII-33, J. I. Beaulne. Saskatchewan: St. Hubert Mission, 14-IX- 43, Fraxintis, P. A. Mullie. US.\: Colorado: Denver, 3- VI-49, F. americana; Ft. Collins, VII-52, F. americana, T. O. Thatcher; Laport, 6-III-50, T. O. Thatcher. Iowa: Lake Okoboji, 17-VI, L. L. Buchanan. Kansas: Rilev, VI- 17, Popeno. Michigan: Detroit. Minnesota: Laverne. VIII-37, .^sh, H. R. Dodge; Ramsey Co.. 8-V-,36, H. R. Dodge. North Dakota: Emmons Co., McHenry Co., 13- Vl-70, trap, A. D. Tagestad; Pierce Co., lO-VI-71; Ram- sey Co.. 31-VII-70, F. pennsylvanica, A. D. Tagestad. South Dakota: Millbank. 19-IX-99. F. americana, J. M. Aldrich. Host.— Fraxinus americana, F. pennsylvanica. Biology.— Apparently as in aculeatus. Notes.— The above descriptions were based on the holotype and on 146 other specimens. 5. H ylesinus fasciatus heConte Hylesinus fasciatus LeConte, 1868, Trans. Amer. Ent. Soc. 2:170 (Holotype, male; York Co., Pennsylva- nia; Mus. Comp. Zool., 973) Diagnosis.— The black and white scale pattern and the uniseriate rows of scales on at least part of declivital interstriae 2 clearly distinguish this species and mexicanus (Wood) from other American representatives of the genus. From mexicanus it is distin- guished by characters summarized in the above key. Male.— Length 1.8-2.3 mm, 1.8 times as long as wide; color almost black, with black and white scales, black scales predominating. Frons rather broadly, deeply concave from epistoma to slightly above upper level of eyes, median line very feebly elevated; lower third of lateral margins rather broadly rounded; surface minutely reticulate- subgranulate, punctures rather fine, obscure; vestiture of moderately abundant, rather short, subplumose setae. Pronotum 0.70 times as long as wide; widest at base, sides arcuately converging to very broadly rounded anterior margin; sur- face minutely reticulate-granulate, finely, closely obscurely punctured; anterolateral areas each bearing about a dozen coarse as- perities, marginal row on median half obso- lete; median line indicated on most of poste- rior half; scales rather large, broad posteriorly, rather slender anteriorly; white scales largely restricted to posterolateral areas. Elytra 1.3 times as long as wide, 2.2 times as long as pronotum; outline and basal mar- gins essentially as in aculeatus; striae rather narrowly impre.s.sed, punctures rather ob- scure; interstriae slightly less than twice as wide as striae, submarginal crenulations as in aculeatus but smaller, rows of discal crenula- tions or tubercles ab.sent, punctures obscured by vestiture. Declivity convex, rather steep; interstriae 2 impressed but convex, 1 slightly elevated, 3 and 9 not noticeably elevated, tu- bercles not evident. Vestiture consisting of moderately large, strongly keeled (tripartite) scales in three irregular ranks except unise- riate on declivital interstriae 2, each scale slightly longer than wide; median row on each interstriae distinctly longer than ground cover; color black except small white patches on interstriae 1 and 2 just behind scutellum, on 6 at similar level, on 2 to 5 and 7 at base of declivity, and on apex of 9. Female.— Similar to male except frons planoconvex, upper three-fourths bearing a rather strongly elevated median carina; fewer elytral scales keeled in ground cover. Distribution.— Pennsylvania and New Jersey to Missouri. US.\: District of Columbia: \\'a,shington, V-29. Mis- souri: Jefferson City, V-17. New Jersey: Glemton, V-20. Pennsylvania: Harrisburg, 1923, Ash, Champlain. West Virginia: Kanawha Station, Fraxinus. A. D. Hopkins; Wood Co., 14-VII-08, A. D. Hopkins. Host.— Fraxinus americana. Biology.— Evidently similar to aculeatus. Notes.— The above descriptions were based on the holotype and on 187 other specimens. 6. Hylesinus mexicanus (Wood) Leperisinus mexicanus Wood, 1956, Canadian Ent. 88:249 (Holotype, male; Tecamachalco, Puebla, Mexico; Snow Ent. Coll., Univ. Kansas) Diagnosis.— This species is distinguished from fasciatus LeConte by characters sum- marized in the above key. In addition, the fe- male frontal carina is less strongly elevated, and most specimens have the light colored scales in the declivital ground vestiture tinted yellow. 116 Great Basin Naturalist Memoirs No. 6 Male.— Length 2.3-2.9 mm, 1.8 times as long as wide; color almost black, with patch- es of black, white, and yellowish tan scales. Frons as in fasciatiis except setae slightly longer. Pronotiim as in fasciatus except patches of white scales larger, also a patch of white scales just behind anterior margin. Elytra as in fasciatus except uniseriate rows of fine, interstrial tubercles present on basal half of disc; erect, uniseriate, median row of scales longer on disc and on declivity almost twice as long as ground vestiture, pale erect scales white in color, pale ground cover scales at least on declivity usually yellowish tan (in some specimens these also entirely white). Pale scales on basal half of elytra and at base of declivitv forming almost contin- uous, transverse bands of white color, posteri- or one continued in lateral area to apex and sometimes joining anterior band (color pat- tern highly variable); pale scales usually com- prise at least half of total number. Female.— Similar to male except frons planoconvex, with a conspicuous median ca- rina, upper half of carina less strongly ele- vated than in fasciatus; only longer, erect, in- terstrial scales strongly keeled. Distribution.— Durango and SW Texas to Puebla. USA: Texas: Big Bend N. P. in Pulliam Canyon, 17-V- 59, 28()0 ni, H. Howden; Rivers, 27-VI-38, r' I. Sailer; Waco, 2X1-39, P. A. Click. MEXICO: Aguascalientes: Agviascalientes, 12-VI-65, 21(X) m. No. 42, S. L. Wood. Durango: Quencame, 23-IV-77, "palo bianco," M. M. Furni.ss; San Juan del Rio, 25-VII-53, 1800 m, S. L. Wood. Puebla: Tecaniaclialco, 2-VII-53, S. L. Wood. Host.— A small desert tree (Oleaceae). Biology.— The habits apparently are es- sentially as in aculeatus. Notes.— The above treatment was based on the holotype and on 56 other specimens. The specimens from Three Rivers, Texas, and the one from San Juan del Rio, Durango, were previously referred by me (Wood 1956:248) to fasciatus. It is now recognized that they are small representatives of mexi- canus, with a higher percentage of black scales than is normal for this species. 7. Hylesinus aztecus Wood Hylcsinus aztecus Wood, 1980, Great Basin Nat. 40:354 (Holotype, male; Chapingo, Mexico, Mexico; Wood Coll.) Diagnosis.— This species is distinguished from califomicus (Swaine) by the larger size, by the presence of a fine, low, median frontal carina in both sexes, by the less strongly con- cave male frons and less strongly convex fe- male frons, and by differences in the declivi- tal interstrial setae described below. Male.— Length 3.8-4.2 mm, 1.8 times as long as wide; vestiture of dark brown and tan scales in a pattern similar to califomicus. Frons similar to califomicus except very shallowly concave from epistoma to upper level of eyes, a low, median carina on lower half, and granules on upper areas of head conspicuously larger. Pronotum similar to califomicus except as- perities smaller, punctures smaller, less defi- nite, and scales averaging much more slender. Elytra similar to califomicus except inter- strial crenulations more numerous, smaller, confused (a median row not predominating); declivital interstriae 1 less strongly elevated, 2 wider; ground setae on declivital interstriae 2 in two indefinite ranks (never uniseriate); erect setae always absent on 2, present on 1 and 3, each four to eight times as long as wide, spaced within a row by distances great- er (one to four times) than length of a seta. Female.— Similar to male except frons less strongly, more broadly impressed (irregularly flattened); declivital interstriae 1 less strongly elevated (vestiture not clearly sexually dimorphic). Distribution.— Mexico. MEXICO: Mexico: Chapingo, 12-XII-1978, Fraximis itlidei, T. H. Atkinson. Biology.— The habits apparently are as in aculeatus. Notes.— The above treatment was ba.sed on the type series of 14 specimens. 8. Hylesinus califomicus (Swaine) Fig. 47 Lcpehsinus califomicus Swaine, 1916, Canadian Ent. 48:190 (Holotvpe, female; San Diego, California; Canadian Nat'. Coll., 9249) Leperisinus hofcri Blackman, 1943, Proc. U.S. Nat. Mus. 94:394 (Holotype, female; Sabino Canyon, Ari- zona; U.S. Nat. Mus., 56573); Wood, 1971, Great Basin Nat. 31:147. Synomjmy Leperisinus califomicus Essig, 1957, Insects and Mites of Western North .America, p. 519. \omen nudum Diagnosis.— This is the most common and most widely distributed representative of the 1982 Hylesinini 117 genus in western North America. This species margins of the elytra, flattened and im and guaternalensis Wood have long, hairlike, pressed interstriae 2 (at least in the male) erect, bristles on discal interstriae 8 to 10, a and the longer, erect interstrial scales on the larger patch of hairlike setae near the basal declivity that indicate a close relationship to Fig. 47. Hylcsinus califomicus: Adult, dorsal aspect, and tralleries. (After Swainc 1916:pl. 8. 118 Great Basin Naturalist Memoirs No. 6 one another. This species is distinguished from guatemalensis by characters summa- rized in the above key, and by the whitish tan color of the pale scales. Male.- Length 2.0-3.1 mm, 1.95 times as long as wide; color dark brown, with color pattern formed by dark brown and light tan scales. Frons concavely impressed on a triangular area from epistomal margin to upper level of eyes; epistomal margin feebly, narrowly ele- vated, broadly, shallowly emarginate; surface reticulate, finely, rather closely, obscurely punctured except at center of concavity; ves- titure rather fine, moderately long, abundant. Pronotum 0.71 times as long as wide; widest at base, sides arcuately converging to narrow constriction just behind very broadly rounded anterior margin; surface reticulate, punctures large but obscure, on middle third their anterior margins finely asperate, lateral areas each bearing about a dozen and a half coarse asperities, with submarginal row obso- lete on median half of anterior margin; scales large, broad in pale areas, in dark areas sim- ilar scales supplemented by dark, slender bristles. Elytra 1.3 times as long as wide, 2.1 times as long as pronotum; sides slightly wider near base, almost straight, converging slightly pos- teriorly on slightly less than basal two-thirds, rather narrowly rounded behind; anterior margins each armed by about 13 crenula- tions; striae slightly impressed, punctures moderately large, deep; interstriae slightly less than twice as wide as striae, each with a uniseriate row of narrow crenulations, crenu- lations increased in number at base, confused, particularly on 2 and 3. Declivity convex, moderately steep; striae not impressed, punc- tures somewhat reduced; interstriae 1 moder- ately, 3 and 9 feebly elevated, 2 flat, rather strongly impressed. Vestiture largely of rather large, pubescent or subplumose scales in about three ranks on each interstriae, part of median rank longer, erect; erect setae slen- der, almost hairlike toward base, becoming scalelike on 1 one-third from base, at margin of declivity on 3 and 4, below middle of de- clivity on 5; each erect seta at least twice as long as ground scales, much longer on sides; none of scales keeled. Female.— Similar to male except frons convex on upper two-thirds, a large, short, subtuberculate carina on lower half, above epistoma; epistomal margin not emarginate; erect interstrial scales shorter, less than twice as long as ground scales. Distribution.— Oregon and North Dakota to Chihuahua and Texas. USA: Arizona: Chiricahua Mts., Glendale, Hviachuca Mts., Miller Canyon in Huachuca Mts., Oak Creek Can- yon, Patagonia, Phoenix, Sabino Canyon, Tucson, Tubao. California: Grass Valley, Inyo Co., Mare Island, Merced, Mission Valley in San Diego Co., Palo Alto, San Diego. Colorado: Greeley. New Mexico: Meek. North Dakota: Bottineau Co. Oklahoma: Holdenville. Oregon: Eugene, Forest Grove, Junction City, McMinnville, Portland, Salem. Texas: Brownsville, Cameron Co., Ft. Davis, Hidalgo Co. Utah: Moab, Provo, Vernal. MEXI- CO: Chihuahua: Colonia Juarez. Hosts.— Fraxinus americana, F. latifolia, F. pennsylvanica, F. velutina, and Olea enropeae. Biology.— Evidently indistinguishable from aculeatus. Notes.- The above descriptions were based on the holotypes of calif ornicus and Jwferi and on 242 other specimens. Blackman evidently was unfamiliar with the full distribution of this species and based his hoferi on minor characters that vary with- in series. Examination of his type series leaves no doubt that this is a synonym of Swaine's species. Through an error in citing calif ornicus the author name was changed from Swaine to a new species designation in the 1957 revision of Essig's book, resulting in a name for which a description was not given or a type specimen designated. 9. Hylesinus guatemalensis (Wood) Lcpcrisinus guatemalensis Wood, 1967, Great Basin Nat. 27:89 (Holotype, female; Volcan Pacaya, Es- quintla, Guatemala; Wood Coll.) Diagnosis.- This species is very closely al- lied to californicus (Swaine), but it may be distinguished by characters summarized in the above key, by the yellow-orange tint of the pale scales, by the more broadly convex upper half of the male frons, and by the nearly complete submarginal row of aspe- rities on the anterior margin of the pronotum. Male.- Length 2.4-3.1 mm, 1.8 times as long as wide; color dark brown, with color 1982 Hylesinini 119 pattern formed by dark brown and light yel- lowish tan scales. Frons broadly concave from epistoma to upper level of eyes; epistomal margin feebly elevated and broadly, very shallowly emargi- nate; surface reticulate, punctures fine, ob- scure; vestiture fine, rather short, rather sparse. Pronotum as in californicus except sub- marginal row of asperities almost complete to median line, and slender setae in median, dark area obsolete; dark scales arranged in a large median and two smaller lateral dia- mond patterns, median one reaching both an- terior and posterior margins. Elytra as in californicus except scales smaller, each about one-fourth as wide as an interstriae, and slender, erect bristles re- placed on interstriae 1 to 4 by erect scales, slender bristles on bases of 5 and 6 and more extensively on 7 to 10; pale scales with a dis- tinct yellow-orange tint. Female.— Similar to male except frons convex above, flattened on lower half, entire- ly devoid of a carina or tubercle, epistoma not at all emarginate; erect interstrial setae shorter, but at least twice as long as ground scales. Distribution.— Guatemala. GUATEMALA: Volcan Pacaya, l-VI-64, 1300 m. No. 661, S. L. Wood. From three host tree species, none of which resembled Fraxititis. Biology.— Evidently very similar to aculeatus. Notes.- The above treatment was based on the type series of 92 specimens. Genus ALNIPHAGUS Swaine Alniphagus Swaine. 1918, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(2):73 (Type-species: Hyle- sinus aspericollis LeConte, monobasic) Hijlmtinoides Spessivetsev, 1919. Ent. Mon. Mag. 55:249 {Type-species: Hylastes alni Niisima); Swaine, 1919, Kept. Canadian Arc. Exp. 3E:279. Synonymii Diagnosis.- From American Hylesinini this genus is distinguished by the elongate an- tennal scape, by the 7-segmented funicle, by moderately flattened, very slightly asymmet- rical antennal club with three sutures, the first of which is partly septate, by the armed anterolateral areas of the pronotum, by the shallowly emarginate eye, by the widely sep- arated anterior coxae, and by the broad, emarginate third tarsal segments. Description.- Length 2.1-3.4 mm, 2.0-2.1 times as long as wide. Frons very slightly dimorphic, male frons weakly im- pressed, female more strongly convex. Eye elongate, shallowly emarginate; finely granu- late. Antennal scape elongate, attaining pos- terior margin of eye; funicle 7-segmented; club moderately flattened, very slightly asymmetrical, marked by three sutures, first partly septate. Pronotum wider than long, anterolateral angles armed by several aspe- rities. Scutellum small, depressed. Elytral bases armed by a long row of overlapping crenulations; declivity convex, rather steep, conservatively sculptured, costal margins not ascending behind. Vestiture hairlike. Distribution.— Western North America and Japan; three species are known; two are from western North America and one is from Japan. Two species recently added to this genus by Schedl (1963:259) appear to be in- correctly placed. Biology.— These monogamous species at- tack the lower bole of alder trees, where they construct unbranched, uniramous, more or less longitudinal egg galleries in the phloem tissues. The larval mines wander in the gener- al direction away from the parental tunnel and may cross one another repeatedly. Ac- cording to Chamberlin (1958:100) the female constructs the entrance tunnel and is later joined by a male. Two generations per year evidently are normal. Special hibernation tunnels are constructed in the outer bark to pass the winter. 1. Key to the Species oi Alniphagus Declivital ground vestiture very short, scalelike, much shorter than on disc; serrations of interstriae 9 and 10, as seen from dorsal aspect, form an almost continuous sawlike lateral profile from base to apex of elytra; larger, darker, with shorter, less abundant pubescence and larger, more numerous interstrial crenulations and tubercles; Alaska to California and Utah; 2.6-3.4 mm 1. aspericollis (LeConte) 120 Great Basin Naturalist Memoirs No. 6 Crenulations on discal interstriae much smaller, less abundant; ground vesti- ture on declivity stout, elongate, as on disc; serrations of interstriae 9 and 10 usually visible from dorsal aspect only at base and in declivital area; smaller, lighter in color, with slightly longer, more abundant pubescence and much smaller, less numerous discal crenulations and declivital tubercles; British Columbia to California; 2.1-2.8 mm 2. hirsutus Schedl 1. Alniphagus aspericollis (LeConte) Figs. 48, 96 Hylesintts aspericollis LeConte, 1876, Proc. Amer. Philos. Soc. 15:380 (Lectotype, male; California, evidently Santa Barbara; Mus. Comp. Zool., 975, present designation) Alniphagus aspericollis: Swaine, 1918, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(2):7,3. Diagnosis.— In addition to the characters siunmarized in the above key, this species is more slender and has very slightly shorter elytral setae than hirsutus Schedl. Male.— Length 2.6-3.4 mm, 2.1 times as long as wide; color dark brown, elytra usually slightly lighter. Frons convex, median area on lower two- thirds weakly impressed, a narrow, transverse impression just above epistoma; surface most- ly reticulate, shining, punctures moderately coarse, very shallow, close; vestiture of sparse, fine, rather short, inconspicuous hair. Pronotum 0.79 times as long as wide; widest a fourth of length from base, sides moderately arcuate from base, converging slightly, very broadly rounded, almost sub- emarginate in front; surface smooth and shin- ing with very close, moderately deep punc- tures of irregular, small to moderately large size, somewhat reticulate anteriorly; ante- rolateral angles armed by one to three coarse asperities, several smaller asperities scattered in anterolateral areas, including median area near anterior margin; vestiture of stout, hair- like setae, each about equal in length to di- ameter of largest punctures. Elytra 1.55 times as long as wide, 2.2 times as long as pronotum; sides almost straight and parallel on basal two-thirds, rather broadly rounded behind; basal margins each armed by 13 low crenulations; striae weakly im- pressed, punctures rather coarse, deep; inter- striae wider than striae, each armed by a somewhat uniseriate row of coarse crenula- tions, most at least half as wide as interstriae, supplemental fine punctures rather obscure. Declivity convex, steep; interstriae 1, 3, 5, 7, and 9 moderately elevated, 1 and 3 each armed on upper two-thirds by six to eight pointed tubercles. Vestiture of stout, recum- bent, interstrial hair on disc equal in length to diameter of a strial puncture, shorter, scalelike on declivity, and erect rows of sparse, interstrial, hairlike setae, each one- third as long as distance between rows. Female.— Similar to male except frons more nearly convex; lateral asperities on pro- notum evidently very slightly larger; declivi- tal tubercles extend to apex. Distribution.— Alaska to California and Utah. ALASKA: Hollis. CANADA: British Columbia: Agas- siz, Barkerville, Bowser, Boyston, Cowichan, Gold- stream, Haspencolls on Goat River, Massett on Queen Charlotte Islands, Metlakatla, Pender Harbor, Terrace, Vaseaux, Victoria. USA: California: Bass Lake, Eureka, Fieldbrook, Hat Creek, Haviah, Marin Co., Mt. Ta- malpais. Placer R. S. in Madera Co., Placerville, Scotia, Taylorville, Ventura, Yosemite N. P. Idaho: Deary, Kas- sel' Oregon: Astoria. Colestein, Corvallis, Dever, Forest Grove, Gardner, Gold Lake in Willamette N. F., Hood River, Newport, Neil Creek, Otis, Portland, Santiam N. F. Utah: .\merican Fork Canyon. Washington: De Moines, Hoquiam, Miller Lake, Puyallup, Quinault, Seattle. Hosts.— A/nw5 rhombifolia, A. rubra, and A. tenui folia. Biology.— As described for the genus. Notes.— The above descriptions were based on LeConte's syntypes and on 310 other specimens. Inasmuch as a type has not been desig- nated from the five syntypes in the LeConte collection, I here designate the first speci- men, a male, as the lectotype for the species as cited above. 2. Alniphagus hirsutus Schedl Figs. 49-50 Alniphagus hirsutus Schedl, 1949, Canadian Ent. 81:2,36 (Holotype, male; Copper Mountain, British Co- hmibia; Schedl Coll.) Diagnosis.- This species is very closely related to aspericollis (LeConte) but can be distinguished, with difficulty, by the charac- ters summarized in the above key, by the 1982 Hylesinini 121 stouter body, and by the slightly longer ely- tra! setae. Male.- Length 2.1-2.8 mm, 2.0 times as long as wide; color of pronotum reddish brown, elytra usually somewhat yellowish brown. Frons as in aspericollis. Pronotum 0.75 times as long as wide; as in aspericollis except sides more strongly ar- cuate; pimctm-es less definite but more imi- form in size, vestiture longer, each seta more than twice as long as diameter of a large puncture. Elytra 1.40 times as long as wide, 2.1 times as long as pronotum; outline as in aspericollis, but stouter; basal margins each armed by 11 crenulations; striae feebly impressed, punc- tures large, rather indistinctly impressed; in- terstriae wider than striae, each armed by fine, low crenulations, each usually less than Fig. 48. Alniphagus aspericollis: Dorsal aspect. (After Bright 1976:207.) one-third as wide as interstriae, supple- mented by moderately large punctures. De- clivity as in aspericollis except alternate in- terstriae less strongly elevated, tubercles much smaller, less than four on each inter- striae. Vestiture with ground vestiture slightly longer, not scalelike on lower declivi- ty, erect setae longer, at least half as long as di.stance between rows. Female.— Similar to male except frons more nearly convex; pronotal asperities larger. Distribution.- British Columbia to California. CANADA: British Columbia: Copper Mountain, 22- V-29, Alniis sitchensis. G. S. Smith; Lorna, 21-VI-25, 17202 lot 35.56, Pinus contorta (error, beating record only); 7 miles N Oliver, 18-V-58. H. Hovvden. USA: Cali- fornia: Cliff Lake, Siskiyou Co., 28-VII-39, Alnus tenui- folia, W. D. Bedard. Oregon: Corvallis, l-VIII-39, Alnus, J. Schuh; Gold Lake, Willamette N. F., 16-VI-6L Alnus tenuifolia and A. sinuata. S. L. Wood. Hosts.— Alnus sinuata and A. tenuifolia. Biology.— Essentially as in aspericollis as mentioned for the genus. Notes.— The above descriptions were based on the holotype and on 45 other specimens. Genus PHLOEOBORUS Erichson Phloeoborus Erichson, 1836, Archiv Naturgesch. 2(1):54 (Type-species: Phloeoborus rudis Erichson, sub- sequent designation bv Hopkins, 1914, Proc. U.S. Nat. Mus. 48:126) Phloeotrupes Erichson, 1836, Archiv Naturgesch. 2(1):53 (Type-species: Phloeotrupes grandis Erichson, subsequent designation by Hopkins 1914, Proc. U.S. Nat. Mus. 48:127); Wood, 1978, Great Basin Nat. .38:383. Synonymy Diagnosis.— This genus is not closely al- lied to any other in the American fauna. It is distinguished by the very large size, by the stout body form, by the entire eye, by the 7- segmented antennal funicle and distinctive club, by the near absence of crenulations on the basal margins of the elytra, by the widely separated front coxae, and by the presence of a large propleural fovea in the female. Description.— Length 4.6-13.0 mm, 1.6-1.9 times as long as wide; color dark brown to black. Frons at least partly concave in male, convex in female, usually with a me- dian carina below; eyes large, entire, varying from widely separated to contiguous^ above. Antennal scape elongate, funicle 7- 122 Great Basin Naturalist Memoirs No. 6 Figs. 49-50. AlniphaSP|^ 4^ ' yh M'*^'"' •' V.,:^^' . .-'.'^- ■ ^ '^■., '-r < '•/:" ^^'■r r . ,'>-,v - ,'>! . . ,' , , >; ..' . 'i'-'.---i- ; -' J'.-- iU'-' '' . " ^ - i;-j-.i, :t •: ■ f .;■■•• *,','\J~' ■i-.j'-- -^ V • f/-v /<■*'■,-; .' ■ ■' " ' V'^**^-**;- i; £ *;'!/'■;.■ [ . ; •". ;_ > ■ j;j» ' I' ]^ < ,.; ;.. ri'.^'. .'V ,,v ,■ ■*>'■'. 'v- '■ '■'■- '■-' ' '^- ''"'■''■ ^",i-.-'--.^ '■' 1" mi- ;"■•-::-■ :>.^r=-v4: f-'--'^'^' •i\i' t' . 5 A.f 4 '-.■*■.' >. i -. .i • - ^"'">■ 1' '"'V-^ V ■S\. .. '»Y .Z-^^"; *• V - u' . ' •:' - ' ' \M-^^r%-'\ . '• i ; '■■. " '■ ■' ;",.■ ■ ■'-"*.■" •%-/.C-r- >: ■'■;--.'' .'. " ' i^' ' ■'""-': --. -'.^^ ' '■■ '~ .. "^ '. .- ■' '■ ' %. ''■'■»' '/'■ • './ ,~-:]j\ ' '^'''^■\' ■■ i ^j'^.-^j'jl • -..-A -■'/;/ ^..■■" .",- ".,-■' ' ■-; ■ •■?.?*- ~-'.i: N^ ■"/^■' "r V , ■ ■ '. 'fe;.'^ '-:i. 'Wy. "^'^^y.^^ tz^ Fig. .51. Phloeoborus punctatorugosus: Male, dorsal aspect. 1982 Hylesinini 125 crenulate interstrial asperities, and the sex- ually dimorphic pronotum distinguishes this species from other Central American repre- sentatives of the genus. Male.— Length 4.6-8.1 mm, 1.6 times as long as wide; color very dark brown, almost black. Frons convex above, a rather shallow, triangular, concave impression extending from epistomal margin about three-fourths of distance to upper level of eyes; a weak me- dian carina in impressed area; surface min- utely reticulate, dull; area below upper level of eyes except in concavity bearing low, iso- lated, transverse tubercles; vestiture restrict- ed to concavity, of minute hair, longer to- ward epistoma. Pronotum 0.68 times as long as wide; widest at base, sides feebly arcuate, con- verging on posterior four-fifths, then abruptly narrowed to very broadly rounded anterior margin; surface minutely reticulate, dull, an- terior two-fifths rather finely asperate, ante- rolateral angles unarmed; posterior two-fifths with sparse, shallow, somewhat reniform punctures. Glabrous. Elytra 1.1 times as long as wide; sides al- most straight and parallel on basal half, rather broadly rounded behind; scutellar notch not wider or deeper than scutellum; basal margins abrupt, feebly elevated, crenu- lations not distinguishable; striae very nar- rowly, moderately impressed, punctures very small distinct; interstriae at least four times as wide as striae, minutely reticulate, dull, with minute, sparse, indistinct punctures and sparse, low, rounded crenulations, fewer than a dozen crenulations on each interstriae. De- clivity steep, convex, confined to slightly more than posterior third; strial punctures very slightly larger and deeper than on disc; interstriae 1 weakly elevated, 1 and 3 with two or three fine, low crenulations near up- per margin, minute punctures uniseriate ex- cept moderately confused on 1 and 3; inter- striae 9 narrowly, strongly elevated from junction with 10 to middle of declivity, weakly convex behind. Glabrous. Female.— Similar to male except frons convex, subshining, rather coarselv, shallow- ly, closely punctured, tubercles entirely ab- sent; pronotal reticulaion almost obsolete, shining, entire surface sparsely, finely, rather deeply punctured, asperities entirely absent; small, subacute interstrial crenulations on elytral disc much more abundant, often ex- ceeding three dozen. Distribution.— Southern Mexico to Brazil. MEXICO: Presumably Veracruz. COSTA RICA: San Jose, San Jose, 22-X-63, 130() m, Psidiurn guava, S. L. Wood; Turrialba, 9-III-64, 700 m, at light, S. L. Wood, 20-X-53, Coffea amhica. Hosts.— Coffea arbica, Lecythis costari- censis, Psidiurn guajava; also from Inga in Colombia. Biology.— Adult beetles entered on the under side of large guava logs in shady places in a coffee plantation. They bored through the bark into sound wood on the underside of the log, where they introduced fungal growth that caused a very rapid white rot. The adult tunnels formed no definite pattern, but wan- dered and branched at random. Egg niches were formed along growth rings, either in rings around the tunnel if it cut across the grain, or in rows along the sides if the tunnel paralleled the grain. The old egg timnels were all stained black. The larvae made very long, winding tunnels through the decaying wood. Both larvae and young adults in their pupal cells were inactive during the climax of the Costa Rican rainy season in November. The age of the tunnels and inactivity of the brood suggested only one generation per year. Some decayed logs that could be crum- bled by hand still contained a few living young adults. Notes.— The above descriptions were based on the holotypes of punctatorugosus and breviusculus and on 62 other specimens. Three female syntypes of nitidicollis were ex- amined and the first of these in the Brussels Museum is here designated as the lectotype of nitidicollis Chapuis as cited above; how- ever, I am not entirely convinced that Chap- uis' Brazilian species is the same as punc- tatorugosus that occurs from Veracruz to Colombia. 3. Phloeoborus belti Blandford Phloeoborus belti Blandford, 1897, Biol. Centr. Amer., Coleopt. 4(6): 151 (Holotype, female; Chontales, Nicaragua; British Mus. .\at. Hist.) Diagnosis.— This species is distinguished from rudis Erichson by the reticulate vertex region of the head, bv the more deeply 126 Great Basin Naturalist Memoirs No. 6 subcrenulately punctured pronotum, by the smaller strial punctvires, by the higher inter- strial crenulations, and by the impressed, imarmed declivital interstriae 2. Female.— Length 7.6 mm, 1.7 times as long as wide; color dark reddish brown. Frons as in scaher Erichson. Pronotum as in rudis except punctures deeper, surface in lateral and basal areas ir- regular, subcrenulate, with a few irregular short, confluent grooves near base; surface al- most smooth, a very obscure reticulation in- dicated on both interspaces and punctures. Elytra 1.2 times as long as wide; interstriae rather deeply impressed, punctures small, mostly distinct; interstriae obscurely reti- culate, rather strongly convex, about three to four times as wide as striae, crenulations high, not more than half as wide as an inter- striae, uniseriate on posterior half of 1, 2, and 4, staggered to confused on all of 3 and on basal half of 2 and 4. Declivity broadly con- vex, rather steep, more strongly reticulate; interstriae 2 flat, unarmed, rather narrow, 1 convex, with a row of narrow tubercles de- creasing slightly in size toward apex, 3 sim- ilar to 1 except tubercles slightly larger, apex of 5 joins 3; lateral areas as in rudis. Distribution.— Nicaragua. NICARAGUA: Chontales, T. Belt. Notes.— The above treatment was based on the holotype. 4. Phloeoborus scaher Erichson rhheohoms scaher Erichson, 1836, Archiv Natiirgesch. 2(1);55 (Lectotype, female; Bahia, Brazil; Berlin Mus., present designation) Phloeotrupes ccudatus Blanchard, 1846, In Briille, In- sectes de I'Ameriqiie Meridiconale recneillis par Alcide d'Orbignv 2:204 (Syntvpes; Bolivia; Paris Mus.); Eggers,' 1933, Ent. Nachrbl. 7:17. Synonymy Phloeoborus sericeus Chapuis, 1869, Synopsis des Scoly- tides, p. 13 (Lectotype, male; Cayenne; Brussels Mus., present designation); Eggers, 1942, Arb. Morph. Taxon. Ent. Berlin-Dahlem 9:267. Siimmymy Phloeoborus opacithorax Schedl, 1940, Arb. Morph. Tax- on. Ent. Berlin-Dahlem 7:20 (Syntypes, female; Panzos, Guatemala; Instit. Pflanzenschutzfors- chung Kleinmachnow); Wood, 1974, Great Basin Nat. 34:285. Synonymy Diagnosis.— The rather narrowly sepa- rated eyes, the finely asperate pronotum, the coarsely crenulate elytra with the entire surface reticulate-granulate, the declivital sculpture, and the sculpture of the male frons distinguish this species from other Central American representatives of the genus. Male.— Length 6.4-7.5 mm, 1.7 times as long as wide; color dark reddish brown. Frons broadly, deeply impressed on lower two-thirds of area below eyes, this area with an acute median carina to epistomal margin; a very slight median impression continuing to upper level of eyes, convex above eyes; sur- face reticulate, rather coarsely punctured ex- cept impressed area obscurely punctured; vestiture of sparse, short, stout, yellow bristles in impressed area. Eyes elongate, sep- arated above and below by about one-half to three fourths width of an eye. Scape reaching middle of eye. Pronotum 0.68 times as long as wide; widest about middle, sides moderately ar- cuate, basal and anterior margins about equally, very broadly rounded; anterolateral angles rather coarsely asperate, asperities gradually decreasing in size posteriorly on anterior two-thirds, then coarsely, closely, subasperately punctured to base; surface reti- culate except apices of asperities; vestiture consisting of sparse, very short, stout bristles. Elytra 1.2 times as long as wide, 2.1 times as long as pronotum; sides almost straight and parallel on basal two-thirds, rather broadly rounded behind; basal margins abmptly pre- cipitous, marginal crenulations indefinite, scutellar notch very shallow, indistinct; striae rather strongly impressed, punctures small, distinct; interstriae convex, at least five times as wide as striae, crenulations coarse, close, usually confused, each about one-fourth to two-thirds as wide as interstriae. Declivity convex, steep; strial punctures deeper than on disc; crenulations less than one-fifth as wide as interstriae, becoming uniseriate and decreasing in size imtil often obsolete on lower third. Vestiture consisting of minute, stout bristles, their length usually not exceed- ing diameter of a .strial puncture. Female.— Similar to male except larger, 7.5-9.5 mm, 1.8 times as long as wide; frons convex, with a slight, transverse impression above epistoma, carina present; pronotal as- perities higher and more acute; anterior half of propleura bearing a large, hemispherical 1982 Hylesinini 127 cavity with a marginal fringe of long, yellow hair. Distribution — Veracruz to Brazil. MEXICO: Veracruz: Orizaba, Salle; Cordoba, Salle and Hoge; Santeconiapan, lO-VI-69, H. Howdeii. GUATEMALA: Pantaleon, Champion. BRITISH HON- DURAS: Stan Creek District in Middlesex, 7-V-63, E. C. Welling. NICARAGUA: Chontales, Janson. COSTA RIC.\: Tilaran, Guanacaste, VII-66, leguminous log, J. B. Karren. PANAMA: Barro Colorado Island, Canal Zone, 15-11-64, L. J. Bottomer; Bugaba and Volcan de Chi- riqui. Champion. OTHER COUNTRIES: Brazil, Colom- bia, Jamaica, Trinidad, Venezuela. Biology.— The only biological data relat- ing to this species was supplied by J. B. Kar- ren, who took two males and three females that were walking on or just beginning tun- nels in a fallen leguminous tree. Most speci- mens in collections were attracted to light. Notes.— The above descriptions were based on the syntypes of scaber, sericeus, and opacithorax and on 40 other specimens from Central America. Of the four females speci- mens in the Zoologisches Museum at Berlin only the first two appear to be syntypes; the first of these is here designated as the lecto- type of scaber Erichson, as cited above. Of seven male syntypes now in the Chapius col- lection at Brussels, the third is here desig- nated as the lectotype of sericeus Chapuis, as cited above, because it was listed first in the original description. Central American specimens have the ely- tral crenulations smaller and more numerous than those from South America. Many South American specimens, particularly the males, have the crenulations almost uniseriate on the disc and often as wide as the interstriae. Except for this character, specimens from the two areas do not appear to differ significant- ly. In general, but by no means consistently, the Central American representatives have been treated under scaber and the South American specimens under cristatus Chapuis { = radulosus Blandford and aspericollis Stro- meyer), although the types of these names may be different species. Until the types are available for study, lunulatus Eggers and opacithorax Schedl are also tentatively treated here as variants of scaber. The syn- types of opacithorax fall well within the range or variability of this species. 5. Phloeoborus rudis Erichson Phlocohoma rudis Erichson, 1836, Arcliiv Naturgesch. 2(1):55 (Lectotype, female; Brazil; Zoo!. Mus. Berlin, present designation) Phloeoborus elongatus Chapuis, 1869, Synopsis des Scolytides, p. 13 (Holotype, male; Brazil; Brussels Mus.); Wood, 1973, Great Basin Nat. 33:180. ^ijnonijmij Phloeoborus rugipennis Eggers, 1942, Arb. Morph. Tax- on. Ent. Berlin-Daliem 9:271 (Holotype, female; San Salvador; U.S. Nat. Mus.); Wood, 1973, Great Basin Nat. .33:180. Synonymy Diagnosis.- This very large species has the enlarged tibiae and other features used to characterize Phloeotrupes. In addition to those features this species has the pronotum almost smooth and shining, except for the punctures, and other characters summarized in the above key that distinguish it from other Central American species. Female.- Length 10.2-11.7 mm, 1.8 times as long as wide; color very dark reddish brown to black. Frons shallowly impressed on lower half of area below eyes, convex above; impres.sed area with a median carina to epistomal mar- gin; surface smooth, shining, punctures rather sparse, moderately large, deep; vestiture of fine, short hair confined to impressed area. Eyes subcontiguous above, separated by a distance about equal to one-third width of eye. Scape not reaching middle of eye. Pronotum 0.68 times as long as wide; widest one-third length from base, sides rather weakly arcuate, feebly converging an- teriorly, very broadly rounded in front; ante- rolateral angles with a few subasperate eleva- tions indicated, remainder of surface smooth, shining except feeble reticulation indicated anteriorly, punctures moderately large, rather deep, irregular but close in most areas; a few minute bristles in anterior and lateral areas. Propleura with a large cavity on ante- rior half as in other Phloeoborus. Elytra 1.3 times as long as wide, 2.1 times as long as pronotum; scutellar notch well de- veloped, about five times as wide as scutel- lum; basal margins abrupt, crenulations ob- scurely indicated; striae impressed, punctures coarse, shallow; interstriae less than three times as wide as striae, convex, rather feebly reticulate, crenulations rather low, staggered, each about one-fourth to two-thirds as wide as interstriae. Declivity convex, steep; striae 128 Great Basin Naturalist Memoirs No. 6 deeper but not narrower than on disc, only slightly narrower than interstriae; interstriae reticulate, uniseriate crenulations extended to apex. Vestiture consisting of minute, inter- strial bristles, each distinctly shorter than di- ameter of a strial puncture. Male.- Smaller, about 7.5-8.8 mm, lower frons more strongly, more broadly impressed. Distribution.— Guatemala to Brazil. GUATEMALA: Trece Aguas, Alta Verpaz, O. F. Cook; Cayuga, IV-15, W. Schaus. EL SALVADOR: San Salvador, l-V-57, P. A. Berry. COSTA RICA: Turrialba, Cartago, 13-V-51, O. L. Cartwright; Las Mercedes, F. Nevermann; Eggers adds Hamburgfarm on Rio Reventa- zon, Limon, at light F. Nevermann, and Hacienda Pehlke, Colombia, by Fehlke. PANAMA: Barro Colo- rado Island, Canal Zone, 10-17-V-64, W. D. and S. S. Duckworth; La Chorrera, 18-V-12, A. Busck. Biology.— As described for the genus. Notes.— The above description was based on the Erichson series of rudis, on the holo- types of rugipennis and elongatus, and on 18 other specimens. Of the series of three fe- males and two males now in the Zoologisches Museum in Berlin, it appears that only the first two, both females, were in the original series. The first specimen has been regarded as the type and is here designated as the lec- totype of rudis Erichson, as cited above. The third specimen, a male, bears Eggers' identi- fication label saying "Phloeoborus rudis Er. S = elongatus Chap." The Erichson and Chapuis specimens were compared directly to one another and to my female topotypic homotype of rugipennis. Tribe TOMICINI ToMiciDAE Thomson, 1859, Skandinaviens Coleoptera Synoptiskt Bearbetade 1.145 (Type-genus: Tomicus Latreille, 1802/3) Hylurcini LeConte, 1876, Proc. Amer. Philos. Soc. 15:373 (Type-genus: Hylurgus Latreille, 1807) Dendroctonides Niisslin, 1912, Naturwiss. Zeitschr. Forst- und Landwirtschaft 1912:273 (Tvpe-cenus- Dendwc toni/s Erichson, 1836) ^ ^f h Xylechinides Niisslin, 1912, Naturwiss. Zeitschr. Forst- und Landwirtschaft 1912:273 (Type-genus: Xulechinus Chapuis, 1869) Anatomical features.— The frons is weakly sexually dimorphic, the eye is entire, the antennal funicle is 5- to 7-segmented, the club is symmetrical and feebly to moderately flattened, with sutures indicated, the pro- coxae are contiguous to narrowly separated, the precoxal costa on the prosternum is ab- sent, the pronotum is unarmed (obscurely as- perate in a few South American forms), the metascutellar area is separated from the post- notum by a distinct suture, and the sutural groove on the mesal surface at the base of the elytra continues to the base without a series of interlocking nodules and cavities. Biological features.— All species are monogamous and phloeophagous. The paren- tal tunnels are either biramous or, if mon- oramous, there is a conspicuous turning niche near the entrance tunnel. Eggs are placed in niches, except some Dendroctonus form grooves in which numerous eggs are placed. Larval mines usually follow a definite inde- pendent course without crossing, except some Dendroctonus feed in congress, thereby form- ing extensive, tabular chambers in the cam- bium region. Symbiotic relationships with fungi occur, but are not of a mycetophagous type. Taxonomy.— This tribe apparently shares the same ancestry with the Hylesinini, but exhibits several more advanced characters. All the genera appear to have an American origin; all are more closely allied to the South American fauna than to that from other areas (except that the Eurasian Xyle- chinus pilosus (Ratzeburg) apparently was derived from North America rather recently). The tribe was not fully separable from the Phloeosinini until the fusion of the postnotum to the scutellar area of the metanotum was discovered. The American genera of Tomi- cini are easily distinguished from one anoth- er; those from other parts of the world may be distinguished with difficulty. Genus PSEUDOHYLESINUS Swaine Pseudohylesinus Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1): 11 (Type-species: Pseudohylesinus grandis Swaine -Hylurgus se- riceus Mannerheim, original designation) Diagnosis.— This genus is very closely re- lated to Xylechinosomus Schedl, but it is dis- tinguished by the less strongly impressed male frons, and by the simple sculpture of the elytral declivity. It is also allied to Xyle- chinus Chapuis, but Pseudohylesinus has sev- en segments in the antennal fianicle. Description.— Length 2.2-5.8 mm, 2.1-2.5 times as long as wide; color dark brown to almost black, with abundant light and dark hairlike and scalelike setae. Frons convex, with an arcuate, transverse impression at or just below middle, a median carina on lower half. Antennal scape elon- gate, shorter than 7-segmented funicle; club conical to slightly flattened. Eye entire, elon- gate; rather finely granulate. Pronotum 0.7- L3 times as long as wide; sides strongly constricted just behind anterior margin; sur- face punctate, variously clothed by hair and scales. Scutellum small, depressed. Elytra L2-L9 times as long as wide; sides almost straight and parallel on basal two-thirds, rather narrowly rounded behind; basal mar- gins each armed by about 10-15 overlapping 129 130 Great Basin Naturalist Memoirs No. 6 crenulations; striate, interstriae tuberculate; parental tunnels. The flight period begins as declivity convex, rather steep, alternate in- early as March and continues at a relatively terstriae often weakly elevated. Vestiture of high level until September. One generation ground cover of abundant scales and rows of apparently is the rule in Canada, with up to longer, erect, interstrial bristles. Tibiae essen- two and a partial third generation in the tially as in Xijlechinus. southwestern United States. Individual par- Distribution.— Western North America; ents may reemerge to produce a second or 1 1 species are known. even a third brood. There are three larval Biology.— These monogamous beetles at- instars. tack limbs, bole, and roots of weakened or Notes.— Schedl (1966) indicated that felled coniferous hosts, where they construct Pseudohylesinus Swaine, 1917, and Xijle- biramous parental galleries in the cambium chinosomus Schedl, 1963, are both junior sub- region. According to Bright (1969), the fe- jective synonyms of Pteleobius Bedel, 1888. male initiates the attack before the male ar- Although the first two genera are very close- rives at the new host. Eggs are deposited in ly related and, perhaps, doubtfully distinct individual niches in the phloem. Larval mines from one another, they are fundamentally are moderately long, more or less straight, distinct from and quite unrelated to Pte- and almost entirely in the phloem. They radi- leobius. The relationship to Xylechinus is ate approximately at right angles from the much closer. Key to the Species of Pseudohylesinus (Modified from Bright 1969:15) 1. Frontal rectangle (Blackman 1942:29) 0.9-1.0 times as long as wide; body 2.1-2.4 times as long as wide; segment 1 of antennal club little if any longer than 2 2 - Frontal rectangle 1.0-1.3 times as long as wide; body 2.0-2.2 (2.2-2.4 in gran- ulatus) times as long as wide; segment 1 of antennal club conspicuously longer than 2 8 2(1). Crenulations on elytral bases from striae 5 to humeral angle high, acutely pointed; declivital interstriae 9 usually moderately elevated, commonly more strongly serrate; interstrial hairlike setae finer, short; parental galleries longitudinal 3 — Crenulations on elytral bases usually not higher or more acutely pointed in lat- eral areas; declivital interstriae 9 usually less strongly elevated, less coarsely serrate; interstrial hairlike setae rather short, coarse; parental galleries transverse '^ 3(2). Declivital interstriae 1 and 3 weakly or not at all elevated, 2 as wide as 1 or 3, 1-3 equally armed by fine granules; British Columbia and Alberta to California and Chihuahua; Pseudotsuga menziesii, Tsuga; 2.3-2.9 mm 1. nebulosus nebulosus (LeConte) - Declivital interstriae 1 and 3 moderately elevated, finely serrate, 2 impressed, devoid of granules, narrower than 1 or 3; S California; Pseudotsuga macrocarpa; 3.0-3.5 mm 2. nebulosus serratus Brack 4(2). Declivital interstriae 2 devoid of granules and hairlike setae; interstrial bristles about half as long as distance between rows 5 — Declivital interstriae 2 armed by a few small granules and by a row of hairlike bristles; interstrial bristles almo.st as long as distance between rows 6 5(4). Color pattern of pale and light brown scales, less commonly (northern areas) with some dark brown patches, pale scales often predominate, in patches or not; S Oregon to California; Abies; 2.8-3.7 mm 3. dispar dispar Blackman 1982 ToMiciNi 131 — Color pattern predominantly of dark brown scales, with small patches of pale scales; Washington to central Oregon; Abies procera; 2.6-3.7 mm 4. dispar pullatus Blackman 6(4). Inner surface of large strial punctures reticulate; interstrial scales very small, predominantly dark; pronotum densely punctured; Michoacan; Abies religiosa; 4.4-5.8 mm 5. magnus Wood — Strial punctures small, inner surface smooth; interstrial scales moderately large, predominantly pale or light brown; pronotal punctures close, deeper; smaller y 7(6). Smaller; submarginal crenulations near bases of interstriae 5 and 6 almost al- ways uniseriate, less crowded; lower frons more coarsely, more deeply punc- tured; interstrial tubercles on declivity averaging higher, more acutely point- ed; Utah to Arizona and New Mexico; Abies concolor; 2.7-3.8 mm 6. maculosus Blackman — Larger; submarginal crenulations at bases of interstriae 5 and 6 crowded, usual- ly confused; lower frons finely, more shallowly punctured; interstrial granules on declivity not as high, more broadly rounded; Michoacan to Tlaxcala and Oaxaca; Abies religiosa; 3.4-4.5 mm 7. variegatus (Blandford) 8(1). Female pronotal setae hairlike, male also with slender scales; interstrial bristles very fine (except granulatus), shorter, submarginal interstrial crenulations more numerous, confused in both sexes; mostly slightly larger 9 — Female pronotal setae hair- and scalelike, male scales rather broad; interstrial bristles slightly longer, stout; subcrenulate interstrial granules uniseriate (ex- cept sericeus), occasionally slightly confused at base in female; mostly somewhat smaller 10 9(8). Larger; pronotal punctures averaging slightly larger, deeper, most specimens with lateral margins of lateral punctures granulate to subasperate; strial punc- tures usually larger, deeper, striae often as wide as interstriae; interstrial bristles rather coarse; body 2.2-2.4 times as long as wide; Alaska to California; Abies; 4.0-5.4 mm 8. granulatus (LeConte) — Smaller; pronotal punctures averaging smaller, less strongly impressed, rarely with their lateral margins granulate; strial punctures usually smaller; striae nar- rower than interstriae; interstrial bristles more slender; body stouter, 2.0-2.1 times as long as wide; Alaska to California; Tsuga, Abies; 2.6-4.0 mm 9. tsugae Swaine 10(8). Interstrial subcrenulate granules more abundant and confused at bases; female discal interstrial scales each one to two times as long as wide; arcuate tran.s- verse frontal impression poorly developed in both sexes, frontal rectangle 0.95 (female) - L06 (male) times as long as wide 11 — Interstrial granules usually not more abundant or confused toward bases (con- fused in some female sitchensis); female discal interstrial scales more than twice as long as wide; transverse frontal impression well developed in both sexes, frontal rectangle 1.03 (female) - 1.20 (male) times as long as wide 12 11(10). Female pronotal scales (except near scutellum), slender, varying from almost hairlike to about eight times as long as wide, their apices subacute not divided except near scutellum; male pronotal scales two to six times as long as wide; Washington, Oregon; 2.7-3.8 mm 10. nohilis Swaine — Female pronotal scales stouter, varying from two to six times as long as wide; if appearing more slender, apices palmately divided; male pronotal scales one to about four times as long as wide; Alaska to California and Idaho; 2.5-3.5 n^Ti 11. sericeus (Mannerheim) 132 Great Basin Naturalist Memoirs No. 6 12(10). Pronotal scales more slender, 4-8 times as long as wide in female, 2-3 in male; interstrial granules averaging larger; frontal rectangle 1.0 times as long as wide in female, male 1.2 times as long as wide; Alaska to California; Picea sitchensis; 2.5-3.1 mm 12. sitchensis Swsiine — Pronotal scales stouter, 2-5 times as long as wide in female, subcircular in male; interstrial granules averaging smaller; frontal rectangle 1.06 times as long as wide in female, male 1.4 times as long as wide; British Columbia to California; Pinus; 2.2-2.8 mm 13. pini Wood 1. Pseudohylesinus nebulosus nebulosus (LeConte) Figs. 22, 52, 53 Hylesinus nebulosus LeConte, 1859, Proc. Acad. Nat. Sci. Philadelphia 5:285 (Holotype, male; Table Mountain, California; Mus. Comp. Zool., 1019) Pseudohylesinus nebulosus: Swaine, 1918, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(2):75 Pseudohylesinus nebulosus nebulosus: Bright, 1969, Univ. California Pub. Ent. 54:16. Diagnosis.— This is the smallest (except pini), most slender, and most widely dis- tributed species in the genus; additional dis- tinguishing characters are included in the above key. Male.- Length 2.3-2.9 mm, 2.3-2.4 times as long as wide; color very dark brown, with a variegated surface pattern formed by dark and light scales and hair. Frons broadly convex, a weak transverse impression just above epistoma, a second weak, transversely arcuate impression near middle; lower half with a low, acutely ele- vated, median carina; .surface shining, punc- tures close, rather deep, moderately fine on lower half, coarse above, devoid of granules; frontal rectangle 1.1 times as long as wide; vestiture of fine, short, moderately abundant hair. Pronotum 0.83 times as long as wide; widest near middle, sides on basal half weak- ly arcuate, almost parallel, abruptly nar- rowed anteriorly to .strong constriction on an- terior fourth, rather broadly rounded in front; surface shining, with dense, moderately deep punctures; interspaces about one-third as wide as diameter of a puncture. Vestiture of erect, sparse hair and recumbent scales; .scales on disc mo.stly as long as wide. Elytra 1.7 times as long as wide; sides al- most straight and parallel on less than basal two-thirds, gradually converging on posterior two-thirds, median third at apex very broadly rounded; anterior margin armed by about 11 rather coarse crenulations, extreme lateral one or two larger and pointed, a few sub- marginal crenulations on interstriae 2-6; striae weakly impressed, punctures moder- ately coarse, deep; interstriae almost twice as wide as striae, each with a central row of uniseriate granules of moderate size, remain- ing surface with numerous, fine, confused, very slightly crenulate punctures. Declivity convex, moderately steep; interstriae 1 and 3 feebly, 9 more strongly, convex, 2 narrower than 1 and 3, feebly depressed, tubercles on 1 and 3 as on disc, evidently smaller on 2 or 4-8, a row of rather coarse, pointed denticles on 9. Densely clothed by a ground cover of scales, each slightly longer than wide, nar- rowly rounded at their apices; interstriae each with a uniseriate row of erect, short, slender, bristles, each bristle shorter than dis- tance between rows. Female.— Similar to male except frontal rectangle 0.80 times as long as wide; pronotal scales more elongate, subpalmately sub- plumose; apices of elytral scales usually acu- minately angulate; color pattern less well defined. Distribution.— S British Columbia and Alberta to Chihuahua, except S California. CANADA: Alberta: Banff, Jasper, Maycroff, Waterton Lakes. British Columbia: Aspen Grove, Cherry Ck., Chilcotin, Columbia Lake, Cowishan Lake, Duncan's, Genoa Bay, Hotel Lake at Pender Harbor, Indian Mead- ows and Merritt at Midday Valley, Kaslo, Massett, Momich Ck., Nelson, Peachland, Vancouver, Vangard, Vernon, Wellington, West Lake on Nelson Isl., Williams Lake. USA: Arizona: Chiricahua Mts., Flagstaff, Hanna- gan Camp in Greenlee Co., Jacob's Lake, Miller Canyon ki Huachuca Mts., Pinaleno Mts., Prescott N. F., San Francisco Mts., Santa Catalina Mts., Walker, Williams. California: Big Spring in Plumas Co., Calistoga, Car- ville. Cascade House, Costella, Crescent City, Cypress Ridge in Marin Co., Del Norte, Dutch Flat in Placer Co., Ft. Seward, Georgetown in El Dorado Co., Gas- quet, Happy Camp, Mill Valley, Mt. Tamalpais, Mon- terey, Orick, Oreleans, Plantation, San Francisco, Shingleton, Trinity. Colorado: Colorado Springs, Do- lores^ Durango, Estes Park, Foxton, Rist Canyon in Lari- mer Co. Idaho: Cedar Mt., Centerville, Coeur d'Alene, Franklin Basin Road in Cache N. F., Grimes Pass, 1982 TOMICINI 133 Hailey, Moscow Mt., Placerville, Sand Point. Montana. Bear Paw Mts., Columbia Falls, Helena, Rocky Boy In- dian Res. in Hill Co. New Mexico: Capitan, cioudcroft. Las Vegas Hot Springs, Sandia Mts. Oregon: Numerous localities from every county in the state. Utah: Alta, Beaver Canyon in Beaver Co., Bryce Canyon N. P., Henry Mts., Logan Canyon, Mt. Timpanogos. Washing- ton: Numerous localities from every countv in the state. MEXICO: Chihuahua: La Magdalena, San Juanito. Host.— Psetidotsuga menziesii, less com- monly in Tsuga heterophylla. Biology.— The bole and limbs of recently cut, injured, or unthrifty trees are selected for attack. The longitudinal parental galleries are mostly in the phloem. Larval mines wander erratically and may be imusually long. The winter may be passed either as larvae or adults in Utah. Notes.— The above treatment was based in the male holotype and on 712 other specimens. 2. Pseudohylesinus nebulosus serratus Bruck Pseudohylesinus serratus Bnick, 19.36, Bull. So. Califor- nia Acad. Sci. 35:37 (Holotype, male; West Fork of San Gabriel Canyon, Los Angeles Co., Califor- nia: Ohio State Univ. Coll.) Pseudohylesinus nebulosus serratus: Bright, 1969, Univ. California Pub. Ent. .54:18 Diagnosis.— This subspecies is distin- guished as indicated in the above key. Male.- Length 3.0-3.5 mm, 2.4 times as long as wide. Essentially as in n. nebulosus except de- clivital interstriae 1 and 3 rather strongly ele- vated, 2 depressed and distinctly narrower than 1 or 3, tubercles on 1, 3, 5, 7, and 9 av- eraging larger. Female.— Similar to male but differing much as in female n. nebulosus except that elytral scales appear subpalmately subplumose. Distribution.- Coastal California from Santa Barbara County southward. USA: California: Big Pines, 14-11-57, D. E, Bright; "S. Madre" in Santa Barbara Co.; Henniger Flats, 22-VI-40, Pseudotsuga macrocarpa, C. R. Bruck; Lytic Ck. in San Bernardino Co.; Switzers Camp, San Gabriel Mts., Santa Barbara Co., 18-IV-62, P. macrocarpa, D. E. Bright; San- ta Monica; West Fork, San Ciabriel Canyon, Los Angeles Co., 29-XII-34, P. macrocarpa. R. Kessinger. Host.— Pseudotsuga macrocarpa. Biology.— Evidently as in n. nebulosus. Notes.- The above treatment was based on the holotype, allotype, seven paratypes, and 11 other specimens. The anatomical differences between n. nebulosus and n. serratus are greater than be- tween most species of the genus. In all proba- bility they are specifically distinct. However, when all factors are considered, particularly the hosts and distribution, it appears best to follow Bright and treat them as subspecies until additional information is available. 3. Pseudohylesinus dispar dispar Blackman Pseudohylesinus dispar Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:11 (Holotype, female; Ve- ronia, Oregon; U.S. Nat. Mus., 54026) Pseudohylesinus dispar dispar: Bright, 1969, Univ. Cali- fornia Publ. Ent. 54:20 Diagnosis.- This species is distinguished from n. nebulosus (LeConte) by the larger average size, by the less strongly developed, less pointed lateral crenulations at the bases of the elytra, by the less strongly elevated, Fig. 52. Psetidohylcsinus n. nebulosus: Dorsal aspect. (After Bright and Stark 1973:149.) 134 Great Basin Naturalist Memoirs No. 6 less strongly serrate declivital interstriae 9, by the shorter interstrial bristles, by the hosts,, and by the transverse parental galleries. Male.- Length 2.8-3.7 mm, 2.2 times as long as wide; color very dark brown, with a variegated surface pattern formed by light and dark scales, light colored scales predominating. Frons essentially as in n. nebulosus except transverse impression just above epistoma slightly deeper; frontal rectangle 1.0 times as long as wide. Pronotum essentially as in n. nebulosus except pale scales more evident. Elytra 1.6 times as long as wide; outline as in n. nebulosus except more broadly rounded behind; basal crenulations not higher later- ally or pointed; sculpture essentially as in n. nebulosus except interstrial tubercles more nearly transversely crenulate, declivity some- what more broadly convex, with interstriae 1, 3, and 9 more feebly elevated; declivital tu- bercles on interstriae 3, 5, and 7 evidently av- eraging slightly larger; interstriae 2 as wide as 1 or 3, usually not impressed. Erect inter- strial bristles short, their length equal to about half distance between rows of bristles. Pale scales predominate over tan and occa- sional darker scales. Female.— Similar to male except frons more strongly convex; frontal rectangle 0.90 times as long as wide; pronotal scales up to twice as long as wide, their margins tending to be fringed; elytral scales more elongate, distinctly less than twice as long as wide, their margins fringed. Distribution.— S Oregon to California. USA: California: Numerous records from the couuties of Amador, Eldorado, Fresno, Lassen, Madera, Mari- posa, Modoc, Placer, Plumas, Shasta, Siskiyou, Tuo- lumne. Nevada: Washoe Co. Intermediate specimens were from coun- ties in Oregon: Harney, Jackson, Klamath. Hosts.— Afoies amabilis, A. concolor, A. grandis, A. maganifica, and Tsuga mertensiana. Biology.- Transverse parental galleries are constructed in the bole and larger limbs. One sample was taken from large roots. Notes.— The above treatment was based on 339 specimens. There appears to be a clinal gradient in the color of this species beginning at the south end of the distribution where scales are a mixture of pale (almost white) and light tan. Toward northern California the patches of white scales become smaller in size as the tan scales increase in number and intensity of color, some of them being rather dark brown. In material from southern Oregon, the tan scales have entirely been replaced by dark brown scales. Specimens from central Oregon to Washington have the white scales reduced to smaller patches, with dark scales covering the remaining areas. Bright (1969:21), appar- ently arbitrarily, placed all specimens from Abies procera in a northern subspecies, d. pullatus, and all other material in a southern subspecies, d. dispar. His distribution map (p. 19), however, shows such extensive overlap, with almost no exclusive range for the north- ern race, that his argument for their contin- ued recognition is virtually eliminated. How- ever, as stated by Bright (p. 21), the northern and southern extremes are so strikingly differ- ent some recognition should be given to them. In view of the material before me, I follow Bright's division of the species and recognize all California specimens as d. dis- par. Specimens from the southern third of Oregon exhibit a transition in pattern and color in which many individuals are not clearly assignable to either race. Specimens from central Oregon northward I assign to d. pullatus, although occasional specimens in a series are not as dark as one making an iden- tification might wish. 4. Pseudohylesinus dispar pullatus Blackman Pseudohylcsinus pullatus Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:9 (Holotype, female; Mount Rainier Nat. Pk., Washington; U.S. Nat. Mus., 54025) Pseudohylesinus dispar pullatus: Bright, 1969, Univ. California Puhl. Ent. 54:21. Diagnosis.— For distinguishing characters refer to the above key and to the taxonomic notes under d. dispar Blackman. Male.- Length 2.6-3.7 mm, 2.2 times as long as wide; color very dark brown, with surface color pattern of predominantly dark brown scales with small scattered patches of white scales. As in d. dispar except for the scale color pattern. Female.- Similar to male except differing as female d. dispar differs from male. Distribution.- Central Oregon to British Columbia. 1982 TOMICINI 135 CANADA: British Columbia: Vancouver. USA: Ore- gon counties: Baker, Benton, Clackamas, Columbia, Douglas, Hood River, Lane, Linn, Umatilla. Washington counties: Pierce, Skamania. Hosts — Afofes amabilis, A. grandis, and A. procera. Notes.— The above treatment was based on the holotype, on several paratypes, and on 54 other specimens. The status of this sub- species is discussed under d. dispar. 5. Pseudohylesinus magnus Wood Pseudohtjlesinus magnus Wood, 1956, Canadian Ent. 88:247 (Holotype, female; 25 miles or 40 km W Ciudad Hidalgo, Michoacan, Mexico; Snow Ent. Mus., Univ. Kansas) Diagnosis.— The large size, the black col- or, and the rugose,- reticulate inner surface of the strial punctures distinguish this species from other representatives of the genus. Male.- Length 4.4-5.8 mm, 2.3 times as long as wide; color black, with surface pat- tern of predominantly black scales and small patches of white scales. Frons broadly, evenly convex above, lower half more nearly flattened below weak, ar- cuately, transversely impressed line, rather strongly, transversely impressed just above epistoma; a fine, subacutely elevated median carina on lower half; vestiture of rather short, coarse, moderately abundant hair, on upper half intermixed with scales; frontal rectangle 1.0 times as long as wide. Segment 1 of an- tennal club only slightly longer than 2 or 3. Pronotum 0.82 times as long as wide; widest at base, sides weakly arcuate, con- verging only slightly before rather strong constriction just behind broadly rounded an- terior margin; surface with dense, small, moderately deep punctures, except sub- granulate on anterior fifth, partly obscured by scales. Vestiture of moderately abundant black scales, with small patches of white scales toward base; each scale about twice as long as wide. Elytra 1.6 times as long as wide, 2.4 times as long as pronotum; sides almost straight and parallel on basal three-fourths, rather broadly rounded behind; anterior margins each armed by about 12 low crenulations; striae rather weakly impressed, punctures moderately large, deep, their interiors conspicuously ru- gose-reticulate; interstriae about one and one-half times as wide as striae, crenulations much as in other species but small, narrow, punctures small, deep, rather abundant. De- clivity convex, steep; interstriae 1, 3, and 9 weakly convex toward apex, otherwise essen- tially as on disc. Interstriae covered by abun- dant scales, each scale about twice as long as wide; erect interstrial bristles rather stout, half as long as distance between rows. Female.— Similar to male except frons less strongly convex, scales absent from upper frons but present on vertex; scales evidently always absent from pronotal disc; elytral scales slightly smaller, evidently more abundant. Distribution.— Michoacan. MEXICO: Michoacan: 25 miles or 40 km W Ciudad Hidalgo, 15-Vn-5,3, 2900 m, Abies religiosa, S. L. Wood; 33 miles or 53 km E Morelia, 14-VI-65, .3000 m, No. 48^ A. religiosa, S. L. Wood. Host.— Abies religiosa. Biology.— The lower bole of very large trees is selected for attack. This species is ag- gressive and probably is capable of killing overmature trees. The transverse parental galleries are straight and longer than in other species. After this species was well estab- lished it was joined by the less aggressive var- iegatus (Blandford). Larval mines evidently wander as in other species; only first instar larvae were observed. Notes.— The above treatment was based on two female paratypes and on 34 other specimens. 6. Pseudohylesinus maculosus Blackman Pseudohylesinus maculosus Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:12 (Holotype, female; Chiricahua Mts., Arizona; U.S. Nat. Mus., 54027) Diagnosis.— This species superficially re- sembles sericeus (Mannerheim), to which it is not closely related; it is distinguished by characters presented in the above key. Male.- Length 2.7-3.8 mm, 2.2 times as long as wide; color dark brown, with a varie- gated surface pattern of pale, tan, and brown scales. Frons with general contours as in magnus Wood except lower half slightly more con- vex; surface shining, punctures rather coarse, close, deep, only slightly smaller on lower half; vestiture of short, moderately abundant hair; frontal rectangle 1.0 times as long as 136 Great Basin Naturalist Memoirs No. 6 wide. Antennal club similar to but more elon- gate than in dispar Blackman. Pronotum 0.82 times as long as wide; out- line and surface about as in inagnus except disc more convex, median line evident; scales large, moderately abundant, each about twice as long as wide. Elytra 1.6 times as long as wide, 2.4 times as long as pronotum; outline as in magnus; basal margins each armed by 12 crenulations, lateral ones slightly higher; striae slightly im- pressed, pvmctures rather large, deep; inter- striae about one and one-half times as wide as striae, crenulations coarse, high, those at bases of 2-4 larger, confused, uniseriate on bases of 5 and 6, pimctures fine, deep, rather abundant. Declivity rather steep, convex; in- terstriae about equally, weakly convex except 9 slightly higher, 2 slightly depressed; crenu- lations modified to slender, rather widely spaced denticles, denticles slightly larger on odd-numbered interstriae. Vestiture of ground cover of abundant scales, each only slightly longer than wide, pale and brown about equal in numbers, arranged in irregular patches, a few tan scales on some specimens; bristles short, rather stout, each about half as long as distance between rows, bristles pres- ent on declivital interstriae 2. Female.- Similar to male except frons more strongly convex; pronotal scales less abundant, each about four times as long as wide, many of them subpalmately subplumose. Distribution.— Utah to Arizona and New Mexico. USA; Arizona: Grand Canyon N. P., 30-V-69, A. lasiu- carpa, W. G. Harwood; Jacob's Lake, 31-V-69, A. con- color, A. kisiocarpci, W. G. Harwood; Graham Mts., 28- VII-33, lot 64, Parker; Grand Canyon; Mt. Lemon, Pima Co., 5-VIII-68, A. lasiocarpa, D. E. Bright; Rustler's Pk, Chiricahiia Mts., 7-VI-69, A. concolor, S. L. Wood; Mill- er Canyon, Hviachuca Mts., 7-VI-69, A. concolor, S. L. Wood. Pinaleno Mts., 15-VII-68, A. concolor, D. E. Bright; Santa Catalina Mts., 5-VIII-68, A. concolor, D. E. Bright. New Mexico: Cloudcroft, 2-VI-69, 29(K) m. No. 58, A. concolor, S. L. Wood. Utah: Payson Canyon, 25-VII-62, Abies concolor, S. L. Wood; Beaver, 22-IV-50, A. concolor, S. L. Wood. Hosts.— Afoies concolor, rare in A. lasiocarpa. Biology.- The bole of fallen, cut, or un- thrifty trees is selected for attack. Parental tunnels are transverse. They are found most commonly at the butt of dying standing trees. They can reproduce in Alpine fir, but prob- ably cannot sustain a breeding population in it. Notes.— The above treatment was based on the holotype and on 124 other specimens. Bright (1969:22) treated maculosus as a synonym of variegatus (Blandford), but in- cluded (p. 37) a note from my observations suggesting a need for further study of these forms. In view of the very slight anatomical differences presented above, including the distinctly smaller average size, and the differ- ence in larval habits, I prefer to recognize them as specifically distinct. The larval mines in maculosus are always exposed at the cam- bium on the surface of peeled bark; they are comparatively short and wander rather indiscriminantly. 7. Pseudohylesinus variegatus (Blandford) Hijlastes variegatus Blandford, 1897, Biol. Centr. Amer., Coleopt. 4(6): 145 (Holotype, female, erroneously said to have come from Volcan de Chiriqui, Pan- ama; British Mus. Nat. Hist.) Pseudohylesinus mexicanus Blackman, 1942, U.S. Dept. Agric. Misc. Pub. 461:13 (Holotype, female; Dis- trko Federal, Mexico: U.S. Nat. Mus., 54028); Bright and Stark, 1973, Univ. California Pub. Ent. 54:22. Synonymy Diagnosis.— This species is very similar to maculosus Blackman, but it is distinguished by the larger average size, by the more abun- dant, confused, submarginal crenulations at the bases of interstriae 5 and 6, by the more finely, more shallowly punctured lower half of the frons, by the' slightly smaller, more rounded interstrial tubercles on the declivity, and by the xylophagous mining habit of the larger larvae. M.\LE.- Length 3.4-4.5 mm, 2.2 times as long as wide; color dark brown, with a varie- gated surface pattern of pale to tan and dark brown scales. In addition to characters mentioned in the above diagnosis, this species differs from maculosus in having some scalelike setae on upper half of frons; and more dark brown scales present on elytra. Female.- Similar to male except frons more strongly convex; scalelike setae absent from upper half of frons; pronotal scales mostly abraded, each about four times as long as wide, mostly subpalmately 1982 TOMICINI 137 subplumose; interstrial scales largely abra- ded,more slender, mostly subplumose. Distribution.— Michoacan to Tlaxcala and Oaxaca. MEXICO: Hidalgo: E! Chico, Pachuca. Mexico: 6 km W Rio Frio, 14-VII-53, Abies religiosa, S. L. Wood. Michoacan: 33 miles or 53 km E Morelia, 14-VI-65, 3000 m. No. 48, A. religiosa, S. L. Wood. Nuevo Leon: Cerro Potosi, 3-V-71, .3300 m, Abies, D. E. Bright. Oaxaca: 53 miles or 85 km S Valle Nacional, 24-V-71, Abies reli- giosa, D. E. Bright. Tlaxcala: 18 km N Tlaxco, 2900 m. No. 21, A. religiosa, S. L. Wood. Host.— Abies religiosa. Biology.— This species was common in the bole of large fallen, cut, and unthrifty trees. The parental galleries are transverse and rather long. Larval mines are almost straight, very long and parallel to the grain of wood; for about half their length they are vis- ible in the phloem on the surface of peeled bark, then they turn abruptly into the wood. The remaining half of their length is about 1 cm below the wood surface and parallel to the fibers; pupation occurs in the wood. Notes.— The above treatment was based on 123 specimens. The holotype is labeled Volcan de Chi- riqui, Panama, but Abies does not grow south of Honduras. This specimen probably came from southern Mexico or Guatemala. 8. Pseudohylesinus granulatus (LeConte) Hylastes granulatus LeConte, 1868, Trans. Amer. Ent. Soc. 2:175 (Holotype, male; blue disk signifying Oregon; Mus. Comp. Zool., 956) Pseudohylesinus granulatus: Swaine, 1918, Dom. Can- ada Dept. Agric. Ent. Br. Tech. Bull. 14 (2):74 Diagnosis.— This species is distinguished from tsugae Swaine by the larger size, by the larger, deeper, subasperate, pronotal punc- tures, and by the more slender body form. Male.- Length 4.0-5.4 mm, 2.2-2.4 times as long as wide; color dark brown, with a sparse covering of light and dark scales. Frons about as in maculosus Blackman ex- cept more elongate, punctures somewhat coarser, impressed area above epistoma slightly stronger and more extensive; frontal rectangle 1.1 times as long as wide. Segment 1 of antennal club as long as 2 and 3 combined. Pronotum 0.88 times as long as wide; widest just behind middle, sides on basal two- thirds rather strongly arcuate, rather strongly constricted on anterior third, broadly rounded in front; surface shining, rather coarsely, closely, deeply punctured, lateral margins of most punctures at least weakly subasperate. Vestiture of sparse, short, rather stout hair; a few scales at base, each about four times as long as wide. Elytra 1.6 times as long as wide, 2.2 times as long as pronotum; outline about as in maculosus; striae weakly impressed, punc- tures rather coarse, very deep, smaller to- ward base; interstriae about as wide as striae, weakly convex, each armed by a row of coarse, tuberculate crenulations, crenulations confused toward base on 2-5, punctures fine, subgranulate, confused, moderately abun- dant. Declivity steep, convex; interstriae 1, 3, and 9 rather weakly convex, 2 depressed, fine tubercles on odd-numbered interstriae. Vesti- ture of sparse, slender scales, each about four times as long as wide, more abundant on de- clivity; erect bristles rather short, stout, each about half as long as distance between rows, absent on 2 on declivity. Female.— Similar to male except frons more strongly convex; pronotum devoid of scales; scales on elytral disc largely abraded. Distribution.— Alaska to California. ALASKA: "Nauacin." CANADA: British Columbia: Bowser, Nonausco, Steelhead, 12 miles or 19 km S To- fino. USA: California: .Alpine Lake, Badger Pass, Car- mel, Chester, Cisco, Eldorado Co., Eureka, Facht, Fall- en Leaf Lake, Fieldbrook, Giant Forest in Tulare Co., Humboldt Co., Kaweah, King's River in Fresno Co., Meadow Valley in Plumas Co., Mendocino Co., Philips, Placer Co., Sequoia N. P., Shingletown, Trinidad, Tuo- lumne Co., Yosemite Valley. Idaho: Couer d'Alene, Mos- cow. Oregon: Blue Mts., Bly. Branden, Cannon Beach, Corvallis, Hood River, Mary's Peak, Odell Lake, Prine- ville, Santiam Junction, Stayton, Sweet Home in Linn Co. Washington: Carlyon Beach, Clear Lake, Kanaskut, La Grande, Lyman, Mineral, Moclips, .Mt. Rainier, Seattle, Satsop. Hosts.— Abies amabilis, A. grandis, A. lasiocarpa, A. magnifica, A. procer, and Tsuga Heterophylla. Biology.— This species constructs trans- verse parental galleries at the base of un- thrifty standing trees or near the ground in large cut or fallen trees. Notes.— The above treatment was based on the male holotype and on 94 other specimens. 138 Great Basin Naturalist Memoirs No. 6 9. Pseudohylesinus tsugae Swaine Pseudohylesinns tsugae Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1): 11 (Holo- type, female; Vancouver, British Columbia; Ca- nadian Nat. Coll., 93.38) Pseudohylesinus obesus Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1); 15 (Holo- type, female; Inverness, British Columbia; Cana- dian Nat. Coll., 9.341); Bright, 1969, Univ. Cali- fornia Publ. Ent. 54:25. Si/nont/mi/ Pseudohylesinus keeni Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:17 (Holotype, female; Cannon Beach, Oregon; U.S. Nat. Mus., 20569); Bright, 1969, Univ. California Publ. Ent. 54:25. Synonymy Pseudohylesinus similis Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:18 (Holotype, female; Par- adise Vallev, Washington; U.S. Nat. Mus., 54030); Bright, 1969, Univ. California Publ. Ent. 54:25. Synonymy Diagnosis- This species is allied to gran- uJatus (LeConte), but it is distinguished by the smaller size, by the stouter body, by the smoother, more finely punctured pronotum, by the narrower striae, and by the slender in- terstrial bristles. Male.- Length 2.6-4.0 mm, 2.0-2.1 times as long as wide; color dark reddish brown, with an obscure surface pattern of pale and dark cinereus scales. Frons more broadly convex than in granu- latus, with transverse, arcuate impression near middle stronger, carina higher; frontal rectangle 1.1 times as long as wide. Segment 1 of antennal club much longer than either 2 or 3. Pronotum 0.76 times as long as wide; widest near base, sides moderately arcuate on posterior two-thirds, strongly constricted on anterior fourth, broadly rounded in front; sur- face shining, pimctures moderately small, dense, rather deep, their lateral margins usu- ally not at all granulate. Vestiture of very slender, pale scales, each at least eight times as long as wide, and slightly longer, suberect hair of about equal abundance. Elytra 1.5 times as long as wide, 2.2 times as long as pronotum; outline about as in maculosus Blackman; striae distinctly im- pressed, punctures rather small, very deep; interstriae twice as wide as striae, distinctly convex, crenulations rather fine, confused to- ward base on 2-7, punctures minute, con- fused, subgranulate, rather abundant. Decliv- ity steep, convex; essentially as in granulattis. Vestiture of abundant ground cover of small scales, each about twice as long as wide, mostly pale, with darker areas; interstrial bristles fine, length very slighdy more than half as great as distance between rows. Female.— Similar to male except frons slightly more strongly convex; pronotum de- void of scales except for a few palmately pul- mose scales at base; elytral scales much less abundant (usually abraded), each about four to six times as long as wide. Distribution.- S Alaska to N California. ALASKA: Juneau. CANADA: British Columbia; Bow- ser, Duncan, Emerald Mine, Grouse Mt., Inverness, Mt. Mahleach, Nanaimo, Stanley Park, Steelhead, Van- couver, Victoria, Whonnock Lake. USA: California: Crescent City, Fieldbrook. Oregon: Astoria, Batterson, Boyer, Cannon Beach, Clatsop, Corvallis, Crater Lake, Gold Lake, Marchfield, Marion Forks, Mary's Peak, Mohler, Reedsport, Waldport. Washington: Concrete, Glacier, Hoquiam, Mountlake Terrace, Naselle, Paradise Valley, Sappho, White River. Host.- Tsuga heterophylla, T. merten- siana, and less commonly in Abies procera. Biology.- The parental galleries are basi- cally transverse. These beetles attack the bole and limbs as small as 5 cm in diameter. They normally attack cut, broken, or fallen trees. Notes.— The above treatment was based on the holotypes of tsugae, obesus, similis, and keeni, and on 126 other specimens. 10. Pseudohylesinus nobilis Swaine Pseudohylesinus nobilis Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1):12 (Lecto- type, female; Santiam N. P., Oregon; Canadian Nat. Coll., 9340, designated by Bright, 1967, Ca- nadian Ent. 99:679) Pseudohylesinus furnissi Blackman, 1942, U.S. Dept. Agric. Misc. Publ. 461:21 (Holotype, female; Mount Rainier N. P., Washington; U.S. Nat. Mus., 54031); Bright, 1969, Univ. California Publ. Ent. 54:27. Synonymy Diagnosis.- This species is distinguished from sericeus (Mannerheim) by the more slender scales on the pronotum. Female.- Length 2.7-3.8 mm, 2.1 times as long as wide; as in sericeus except pronotal scales slender, varying from almost hairlike to about eight times as long as wide, except stouter near scutellum; strial punctures ten- ding to be larger (not consistent). Male.- Similar to male sericeus except pronotal scales two to six times as long as wide, their apices usually not palmately divided. 1982 TOMICINI 139 Distribution.— Oregon and Washington. USA: Oregon: Bandon, Abies amabilis- Crater Lake N. P., A. a7nabilis. Gold Lake, Willamette N. F., 16-VI- 61, A. amabilis, S. L. Wood; Lost Lake, Hood River Co., 25-VII-64, A. amabilis, D. E. Bright; Mary's Peak, Sius- law N. F., 19-VI-6L A. procera, S. L. Wood; Mt. Hood; Santiam Pass, Linn Co., 19-VI-6L A. amabilis, S. L. Wood. Washington; Easton; Longmire, 23-V-35, Hopk. U.S. 20579-A, A. amabilis, F. P. Keen; Mt. Rainier N. P., A. procera; Spirit Lake, A. amabilis; White Pass, Yakima Co., 20-VIII-62, A. grandis, D. E. Bright; White River; Yakima Park. Hosts.— Abies amabilis, and A. procera. Biology.— Basically as in sericeus, but the parental galleries vary from transverse to subvertical. Notes.— This species is exceedingly diffi- cult to distinguish from sericeus. Both species vary considerably and often cannot be recog- nized unless series- are available for study. The above treatment was based on the holo- type of nobilis, on my homotype, on two specimens from Blackman's series, on four from Bright's series, and on 209 other speci- mens. At the time the holotype of furnissi was examined I did not regard nobilis as a distinct species; consequently, I rely on Bright's (1969:28) synonymy for treatment of this name. 11. Pseudohylesinus sericeus (Mannerheim) Hylurgus sericeus Mannerheim, 184.3, Moskov. Obshch. Isp. Prirody, Otd. Biol. Biul. (Bull Soc. Imp. Nat. Moscou) 16(2):296 (reprint p. 124) (Holotype, fe- male; Sitka, Alaska; Univ. Zool. Mus., Helsinki) Pseudohylesinus sericeus: Wood, 1969, Great Basin Nat 29:116,31:69 Pseudohylesinus grandis Swaine, 1917, Dom. Canada Dept. Agric. Ent. Br. Tech. Bull. 14(1): 13 (Lecto- type, female; Saanichton, British Columbia; Ca- nadian Nat. Coll., 9339, designated by Bright, 1967, Canadian Ent. 99:679); Wood, 1969, Great Basin Nat. 29:116. Synonymy Pseudohylesinus yasumatsui Nobuchi, 1971, Bull. Gov. For. Expt. Sta., Tokyo 238:160 (Holotype, male; Takanishi, Nagano, japan; Gov. For. Expt. Sta., Tokyo); Wood, 1977, Great Basin Nat. 37:387. Synonymy Diagnosis.- This species is distinguished from sitchensis Swaine by the broader frontal rectangle in both sexes, with the arcuate, transverse impression poorly developed, by the much stouter, discal, interstrial scales on the female, and by the more numerous, con- fused, interstrial crenulations at the base of the elytra. It is distinguished from nobilis Swaine by the stouter pronotal scales. Male.- Length 2.4-3.3 mm, 2.1 times as long as wide; color dark brown, with a varie- gated surface pattern of pale and of dark brown scales. Frons broadly convex above, somewhat flattened below, but not impressed on ar- cuate line; surface very slightly more rugose than granulatus (LeConte) or tsugae Swaine; vestiture of moderately coarse, rather short hair. Segment 1 of antennal club as long as 2 and 3 combined. Pronotum 0.77 times as long as wide; es- sentially as in maculosus Blackman; scales on disc about one and one-half times as long as wide; much more slender near anterior margin. Elytra 1.5 times as long as wide, 2.2 times as long as pronotum; outline essentially as in maculosus; striae rather narrowly impressed; punctures moderately coarse, deep; inter- striae about twice as wide as striae, moder- ately convex, crenulations rather small, sub- tuberculate, at bases of 2-4 rather crowded, confused. Declivity as in maculosus except interstriae 1, 3, and 9 usually more strongly convex, 2 somewhat depressed and devoid of tubercles and bristles. Scales ovate to sub- circular, each slightly longer than wide, abundant; bristles stout, half as long as dis- tance between rows. Female.— Similar to male except frons more strongly convex, frontal rectangle 0.95 times as long as wide; pronotal scales about two to six times as long as wide, mostly sub- palmately subplumose; elytral scales one and one-half to two times as long as wide (up to four times as long as wide near suture on bas- al half of disc), widest at or beyond their middle, their apices broadly rounded. Distribution.— Alaska to central California. ALASKA: "Sitka." CANADA: British Columbia: Bear Lake near Pender Harbor, Dog Lake near Penticton, Garibaldy Park near Haney, Grouse Mt. near Van- couver, Lake Cowichan, Massett, Matacatla, Mission City, Pender Harbor, Queen Charlotte Islands, Saanich- ton, Sidney, Stanley Park, Steelhead, Vancouver, Wel- lington. USA: California: Carson Ck. in Marin Co., Cres- cent City, Duncan Mills, Facht, Ferndale, Ft. Bragg, Gasquet, Grassy Lake Humboldt Co., Inverness, Kla- math, Lagunitas, Lake Pilarcitas in San Mateo Co., Mt. Tamalpais, Noyo River in Mendocino Co., Orick, Pa- raiso Hot Springs, San Francisco, Santa Cruz Mts., Warner Mts., in Modoc Co. Oregon: Alsea, Ashland, As- toria, Bear Springs, Bly, Boyer, Cannon Beach, Cor- vallis. Crater Lake N. P., Diamond Lake, Florence, 140 Great Basin Naturalist Memoirs No. 6 Glenada, Junction City, Lake of the Woods, Lost Lake, Marshfield, Mary's Peak, McMinnville, Myrtle's Point, Otis, Pinchurst, Pistol River in Curry Co., Santiam Junc- tion, Santiam N. F., Santiam Pa.ss, Scio, Taft, Waldport, Willamette Pass. Washington: American Lake, Bruce Port, Chase Lake, Clear Lake, Forks, Lake Crescent, Longimire, Loveland, Mt. Rainier N. P., Nancotta, Na- selle, Puget, Puyallup, Quinault, .Seattle. Hosts.— Abies amabilis, A. grandis, A. procera, Pseudotsug,a menziesii, and Tsuga heterophylla. Biology.— The somewhat variable trans- verse parental tunnels are cut in the limbs and bole of imthrifty, cut, or fallen trees. Notes.— The above treatment was based on the holotypes, on my homotypes or se- riceus, grandis, fumissi, and yasumatsui, and on 319 other specimens. Confusion concerning the identitv of this species resulted when the specimen, not a type, imder this name in the LeConte collec- tion was thought to be correctly determined. The LeConte specimen and the species treated as sericeiis bv Swaine (1917, 1918), Blackman (1942), and Bright (1969) were transferred to pint Wood (1969, 1971). 12. Pseudohylesinus sitchensis Swaine Fig. .54 Pseudohylesinus sitchensis Swaine, 1917, Dom. Canada Dept. .\gric. Ent. Br. Tech. Bull. 14(1): 12 (Holo- type, male; Menzies Bay, Vancouver Island, Brit ish Columbia; Canadian Nat. Coll., 9342) Diagnosis.— This species is distinguished from sericeus (Mannerheim) by the less crowded basal crenulations that are almost always imiseriate to the base on interstriae 2, 4, and 5, by the much more slender, non- plumose (except on extreme basal margin) setae on the female pronotum, by the more slender interstrial scales in the female, by the stronger, transverse, frontal impression, and by the narrower frontal rectangle. Male.— Length 2.5-3.1 mm, 2.2 times as long as wide; color as in sericeus. Frons as in sericeus except transverse im- pres.sion near middle of frons much stronger; frontal rectangle 1.20 times as long as wide. Pronotum 0.86 times as long as wide; as in sericeus except scales about two to three times as long as wide on disc, more slender near anterior margin. Elytra as in sericeus except crenulations at bases of interstriae 2, 4, and 5 almost always uniseriate; scales on disc two to three times as long as wide; interstrial bristles almost as long as distance between rows. Female.— Similar to male except frontal rectangle 1.03 times as long as wide; pronotal .scales very slender, about eight or more times as long as wide, not .subplumo.se except near basal margin; interstrial scales on di.sc each about four times as long as wide, widest near its base and tapered toward its apex. Distribution.— Alaska to N California. Fig. 53. Pseudohylesinus n. nehulosus: .\ntenna of female. Fig. 54. Pseudohylesinus sitchensis. .\ntenna of male. 1982 TOMICINI 141 ALASKA: Afognak Isl., Juneau, Prince of Wales Isl. CANADA: British Columbia: Menzies Bay, Port Ren- frew. USA: California: Oescent CAiy, Delnorte, Eureka, Klamath, Trinidad. Oregon: Cannon Beach, Mt. Hood, Marshfield, Otis, Seaside. Washington: Hoquiam. Host.— Picea sitchensis. Biology.— The parental galleries are lon- gitudinal and lack a nuptial chamber. The bole of cut and fallen trees is selected for attack. Notes.— The above treatment was based on the holotype and on 79 other specimens. 13. Psetulohylesinus pini Wood Psetidoht/lesinus pini Wood, 1969, Great Basin Nat. 29:122 (Holotype, female; Pacific Grove, Califor- nia, Wood Coll'.) Diagnosis.— This species is very similar to sitchensis Swaine, but it is distinguished by scale characters presented in the following description. Male.— Length 2.2-2.8 mm, 2.2 times as long as wide; color dark brown with a varie- gated surface pattern of pale and or dark brown scales. Frons as in sitchensis except transverse im- pression stronger; frontal, rectangle 1.4 times as long as wide. Pronotum as in sitchensis ex- cept scales broadly oval, each very slightly longer than wide. Elytra as in sitchensis ex- cept interstrial crenulations slightly smaller, discal scales subcircular, each about one to one and one-half times as long as wide. Female.— Similar to male except frontal impression less well developed; frontal rec- tangle 1.06 times as long as wide; discal in- terstrial scales each one and one-half to two times as long as wide, widest at their middle, apical end rather broadly rounded. Distribution.— British Columbia to cen- tral California. CANADA: British Columbia: Massett; Metlaktla. USA: California: Albion, 9-\T-62, Pinus miiricata, Car- mel, 5-IV-25, P. radiata, F. O. Ballon; Carson Ck. in Ma- rin Co.; Cypress Ridge in Marin Co.; Mendocino; Mon- terey, 2-IX-30, P. radiata; Pacific Grove, 12-XII-2.3, P. radiata; San Francisco; San Mateo; 14 miles N and 18 miles N Santa Cniz, P. radiata. Oregon: Florence, 20- VI- 64, P. contorta, D. E. Bright; Glenada; Lane Co., P. con- torta; Newport; Sand Lake; Seaside. Washington: West port. Hosts.— Pinus contorta, P. muricata, and P. radiata. Biology.— The longitudinal parental gal- leries normally have a nuptial chamber. Pre- sumably they attack the same types of host material as sitchensis. Notes.— The above treatment was based on the type series of 4 specimens and on 46 other specimens. Prior to 1969 it was treated under the name sericeus. Genus HYLURGOPINUS Swaine Hylurgopinus Swaine, 1918, Dom. Canada Dept. .\gric. Ent. Br. Tech. Bull. 14(2):74 (Type-species: Hy- lastes rufipes Eichhoff, monobasic) Diagnosis.— This genus is allied to Pseudo- hylesinus and Dendroctonus, from which it is easily distinguished by septate sutures 1 and 2 in the antennal club, by the long, straight, transversely elevated epistomal process above the premandibular lobe, by the small size, and by many other characters. Description.— Length 2.2-2.5 mm, 2.3 times as long as wide; color dark brown. Frons convex; epistomal process broad, over- riding epistomal margin. Eye elongate-oval, entire. Antennal scape rather short, not reaching posterior margin of eye; funicle 7- segmented; club conate, slightly flattened, su- tures 1 and 2 septate, sutures 1, 2, and 3 marked by rows of setae. Scutellum small, transversely oval. Elytral bases armed by a row of moderately high, overlapping crenula- tions; elytra striae conservatively sculptured. Vestiture of stout, almost scalelike ground setae and a row of erect bristles on each in- terstriae. Fore coxae rather widely separated; precoxal lateral ridge of prothoracic sternum obsolete. Third tarsal .segments broad, some- what bilobed. Declivital armature poorly developed. Distribution.— One .species occurs east of the Rocky Mountains in temperate North America. Biology.— Cut or dying boles and limbs of various elms are selected for attack. The bi- ramous parental galleries usually are trans- verse or primarily so; they are primarily in the phloem tissues but may engrave the wood slightly. The larval mines are also in the phloem and are exposed on peeled bark; they tend to follow the grain of the wood. 142 Great Basin Naturalist Memoirs No. 6 Hylurgopinus rufipes Eichhoff Fig. 55 Hylastes rufipes Eichhoff, 1868 (May), Berliner Ent. Zeitschr. 12:147 (Lectotype, sex?; Carolina; U.S. Nat. Mas., 53824, present designation) Hylesinus opaculus LeConte, 1868 (September), Trans. Amer. Ent. Soc. 2:170 (Two syntypes; Pennsylva- nia; Mus. Comp. Zool.); Schwarz, 1896, Proc. U.S. Nat. Mus. 18:606. Synonymy Hylurgops rufipes: LeConte, 1876, Proc. Amer. Philos. Soc. 15:.390. Hylurgopinus rufipes: Swaine, 1918, Dom. Canada Dept. Agr. Ent. Br. Tech. Bull. 14(2):74 Diagnosis.— Although not closely related, this species frequently is confused with Hy- lastinus obscurus (Marsham). This species is easily distinguished from it by the long, straight, elevated epistomal process that part- ly overlays the epistomal margin and by the absence of an elevated ridge between each prothoracic coxa and the anterior margin of the pronotum. Female.— Length 2.2-2.5 mm, 2.3 times as long as wide; color dark brown. Frons convex from vertex to weak trans- verse impression immediately above epistom- al process; epistomal process smooth, slightly elevated, straight; premandibular median epistomal lobe large, depressed below level of epistomal process, its lateral extremities overridden by or merged with epistomal pro- cess; surface smooth, shining between punc- tures, coarsely, very closely, rather shallowly punctured, flattened inner surface of punc- tures with obscure indications of reticulation; vestiture fine, short, inconspicuous, hairlike, except a conspicuous tuft along lower margin of epistomal process. Pronotum 0.84 times as long as wide; widest toward base, sides almost parallel on basal half but weakly arcuate, narrowed, and moderately constricted just behind rather broadly rounded anterior margin; surface unarmed, smooth, shining, punctures coarse, very close, deep, interspaces not wider than half diameter of a puncture; vestiture con- sisting of short, semirecumbent, stout, almost scalelike setae, and slightly longer, erect bristles. Elytra 1.5 times as long as wide, 2.0 times as long as pronotum; sides almost straight and parallel on basal two-thirds to declivital base, rather broadly rounded behind; striae slightly impressed, punctures coarse, deep; interstriae slightly narrower than striae, convex, punc- tures coarse, deep; interstriae slightly nar- rower than striae, convex, punctures tubercu- late (narrow crenulations), uniseriate except somewhat confused on basal half of 3; two or three tubercles at base of each interstriae (ex- cept 1) enlarged to form small submarginal crenulations. Declivity convex, steep; striae wider than on disc, interstriae more strongly convex, with tubercles larger, pointed. Vesti- ture consisting of short, stout, almost scale- like setae each about five or six times as long as wide, and rows of stout erect bristles each about twice as long as ground vestiture; both types of setae extend to base. Male.— Apparently identical to female ex- cept for differences in posterior abdominal terga. Distribution.— SE Manitoba, S Quebec, and Maine to Kansas, Mississippi, and Alabama. CANADA: SE Manitoba, S Ontario, S Quebec. USA: Alabama, Connecticut, Delaware, District of Columbia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Mary- land, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, North Dakota, Ohio, Pennsylva- nia, Rhode Island, Tennessee, Vermont, Virginia, West Virginia. Hosts.— Ulmus spp.; records also exist from Fraxinus, Prunus, and Tilia, although these attacks undoubtedly resulted from ab- normal conditions. Biology.— Cut or dying limbs or bole of the host are selected for attack. They over- winter either as larvae or adults that com- plete development and emerge in the spring. They emerge in May and fly to living trees, where they feed briefly before seeking a Fig. 55. Hylurgopinus opaculus: Lateral aspect of adult; A, anterior face of left protibia; B, posterior face of left antenna. (After Kaston 1936:614.) 1982 TOMICINI 143 dying tree. The monogamous beetles con- struct transverse or somewhat obhque, bi- ramous tunnels in the cambium region, scor- ing the wood lightly. The eggs are deposited in niches along margins of the egg galleries and the larvae radiate out from them in the general direction away from the parental tunnels and parallel to the grain of the wood. There appear to be up to two generations each year in the south, but only one in the north. This species is not aggressive in its at- tacks and had limited economic importance prior to the introduction of Dutch Elm dis- ease. Since then it has been studied rather intensively. Notes.— Because the loss of the Hamburg Museum evidently destroyed all other syn- types, the syntype labeled with a small blue paper triangle, with "nifipes, Carolina, Ger- mar," with "no. 4," with a red "cotype" label no. "53824," and with "Hylastes rufipes Eichhoff, type, = Hylastes opaculus" in the U.S. National Museum, is here designated as the lectotype of this species. In addition to the lectotype of rufipes, the two syntypes of opaculus and 321 other specimens were used to prepare the above treatment. The priority of the name opaculus over ru- fipes was pointed out by Blandford (1898:5) and Wood (1979). Rabaglia and Lanier (1981), in an attempt to correct the error in priority, contributed additional confusion. The name rufipes was validated in May 1868, opaculus in September 1868. Genus XYLECHINUS Chapuis Xi/lechinits Chapuis, 1869, Synopsis des Scolytides, p. 36 (Type-species: Hylesinus pilostis Ratzeburg, monob