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Subfamilies Ephialtinae Xoridinae Acaenitinae By HENRY and MARJORIE TOWNES and Collaborators: G. Stuart Walley, Luella Walkley, Dale Habeck, and George Townes SMITHSONIAN INSTITUTION ¢ WASHINGTON, D.C. « 1960 Publications of the United States National Museum The scientific publications of the United States National Museum include two series, Proceedings of the United States National Museum and United States National Museum Bulletin. In these series are published original articles and monographs dealing with the collections and work of the Museum and setting forth newly acquired facts in the fields of Anthropology, Biology, Geology, History, and Technology. Copies of each publication are distributed to libraries and scientific organizations and to specialists and others interested in the different subjects. The Proceedings, begun in 1878, are intended for the publication, in separate form, of shorter papers. These are gathered in volumes, octavo in size, with the publication date of each paper recorded in the table of contents of the volume. In the Bulletin series, the first of which was issued in 1875, appear longer, sep- arate publications consisting of monographs (occasionally in several parts) and volumes in which are collected works on related subjects. Bulletins are either octavo or quarto in size, depending on the needs of the presentation. Since 1902 papers relating to the botanical collections of the Museum have been published in the Bulletin series under the heading Contributions from the United States National Herbarium. REMINGTON KELLOGG Director, United States National Museum Unirep STATES GOVERNMENT PRINTING OFFICE, WASHINGTON, 1960 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington 25, D.C. - Price $2.50 (paper) 2 Contents Introduction . “ Definition of eramiles! Subfamily Ephialtinae . Key to the tribes of Ephialtinae 1. Tribe Pimplini . ie 2. 14. Key to the Nearctic pede ‘of Swi Genus Exzeristes . Genus Scambus . : Keys to the subgenera of Seambus. Subgenus Endromopoda. Subgenus Lissoscambus Subgenus Afeleophadnus . Subgenus Scambus Subgenus Erythroscambus Genus Calliephialtes . Genus Apistephialtes . Genus Pimpla. Genus Anastelgis . Genus Dolichomitus . . Genus Acropimpla. . Genus Iseropus . . Genus Tromatobia . . Genus Zaglyptus. Genus Clistopyga . Genus Alophosternum Genus Perithous. 2. Tribe Polysphinctini . Be Soe Negrete big 10. ae Key to the Nearctic genera of Polyaphinetint” Genus Laufeia . Genus Schizopyga . Genus Zabrachypus Genus Acrodactyla . Genus Eruga . Genus Piogaster . Genus Oxyrrhexis . Genus Polysphincta . Genus Acrotaphus . Genus Sinarachna . Genus Zatypota . 3. Tribe Ephialtini . Key to the Nearctic ponere ‘of Ripiialtint 1. Genus [toplectis 1 Bee 2. Genus Ephialtes . 3. Genus Coccygomimus . III IV CONTENTS Subfamily Hone eirape oo rae 4. Tribe Theroniini . Key to the Nearctic peeera es Teron 1. Genus Theronia 2. Genus Delomerista . 3. Genus Pseudorhyssa. 5. Tribe Poemeniini. Key to the Nearctic genera ‘of Boemenin 5 1. Genus Poemenia . 2. Genus Podoschistus . 3. Genus Neoxorides 6. Tribe Rhyssini. Key to the Near ene) genera ee Bienen 1. Genus Rhyssa . oho a etgtnacm ve 2. Genus Rhyssella . 3. Genus Epirhyssa . 4. Genus Megarhyssa . Subfamily Xoridinae . Key to the tribes of Monitinne 3 1. Tribe Xoridini . Key to the genera of Mondina: 1. Genus [schnoceros Genus Aplomerus. Genus Odontocolon . Genus Xorides . sys : Key to the subgenera of Kiondes : ‘ Key to the Nearctic subgenera, species groups, onl poeaice of Xorides . 2 . Subgenus Ganenhonus oe . Subgenus Cyanozorides . Subgenus Hpizorides. . . Subgenus Gonioprymnus . Subgenus Moansa. . Subgenus Moerophora . . Subgenus Hromus. . Subgenus Periceros . . Subgenus Xorides. . Subgenus Pyramirhyssa . 2. Tribe apeain 1. Genus Labena . 3. Tribe Labiini 1. Genus Grotea 4. Tribe Poecilocryptini . 5. Tribe Brachycyrtini 1. Genus Brachycyrtus . Subfamily Acaenitinae. ; ‘ Key to the Nearctic genera ioe Aen nenee Genus Coleocentrus . Genus Mesoclistus Genus Arotes Genus Spilopteron Genus Yezoceryx . Peco at SCOWMNANARWNHE -— Spee Figures Indices Page 350 351 351 362 373 375 376 376 387 389 395 395 396 409 413 415 436 437 437 438 438 439 448 489 491 492 494 494 494 495 495 495 496 501 501 530 530 531 537 538 541 541 542 544 545 546 560 561 568 578 580 635 Ichneumon- Flies of America North of Mexico Henry and Marjorie Townes Introduction Tus 18 PART 2 of a series of monographs on the ichneumon flies of America north of Mexico, prepared under a project supported by the Dow Chemical Company, the University of Michigan, and the National Science Foundation. The first paper, on the subfamily Metopiinae, was issued March 6, 1959, as U. S. National Museum Bulletin 216, part 1. The statements in part 1 about bibliography, material studied, and terminology apply also to this paper. References to original descriptions concerning Nearctic material are all given, and references to original descriptions based on exotic material are given where they seem necessary to explain the nomenclature. Papers on biology and morphology are cited, but those which record only hosts or localities, or which are secondary taxonomic references, are omitted. These can be located in a recent catalog, if they are of interest (Townes, 1944, Mem. Amer. Ent. Soc., No. 11, pp. 23-120). Most of the material in the larger North American collections, plus a few smaller lots of specimens, has been studied. The list of collections is the same as for part 1, except that very little of the material in the Corvallis and Edmonton collections was used for this paper. As in part 1, the locality and host records we cite are only from specimens seen by ourselves. Unconfirmed records in literature are omitted. Some of these published records are valuable, but a large percentage are based on incorrect or questionable determinations. In most cases, the specimens on which the determinations were based have been studied again, and we hope they are now being recorded correctly. If a locality or host record in literature is not repeated, it is unconfirmed by our work. For names of the hosts, we have had to accept the statements on the pin labels, which in some cases are Vv; VI INTRODUCTION probably incorrect. We take responsibility for the determination of the parasites, but not of the hosts. The nomenclature of the hosts has been brought into conformity with recent usage, with the assistance of specialists in the U. S. National Museum and the U.S. Department of Agriculture. In discussing the seasonal distribution of a species we have usually disregarded the dates on the pin labels of reared specimens because many of these emerged in an indoors climate, out of their natural season. The morphology of the ovipositor tip is often useful in the taxonomy if these insects, so we have provided a figure (329, 1) explaining its terminology. Other students of ichneumon flies have been helpful in supplying certain bits of information or assistance, comparing specimens with types, or discussing some of the taxonomic problems with us. Miss Luella Walkley of the U. S. Department of Agriculture, Mr. J. F. Perkins of the British Museum (Natural History), Mr. G. Stuart Walley of the Canadian Department of Agriculture, Prof. Toichi Uchida of Hokkaido University, Mr. Gerd Heinrich of Dryden, Maine, and Mr. R. R. Dreisbach of Dow Chemical Company are among these. Mr. Perkins’ special knowledge of the family has made his help valuable. Mr. Walley has placed at our disposal the extensive locality and host information assembled by the Canadian Department of Agriculture. Mr. Dreisbach has been particularly helpful in collecting specimens for this study and being always ready with friendly encouragement. The thorough representation of the State of Michigan in the distributional data is the result of his efforts. In a work that attempts to bring together and use all available information, it is essential to have the cooperation of the scientists and institutions which have been responsible for the gathering of the information and its conservation in accessible form. In the case of this paper the assistance from all sources has been unfailing. Curators of North American collections have lent the specimens under their care, and individuals and institutions the world over have given access to type specimens, or in some cases have sent them through the mails for study. In connection with this paper we have seen or reexamined types in the museums in Philadelphia, Washington, Ottawa, Quebec, Urbana, New Haven, Cambridge, Ithaca, London, Oxford, Brussels, Tervuren, Leiden, Amsterdam, Copenhagen, Lund, Stockhold, Helsinki, Leningrad, Warsaw, Wroclaw, Berlin, Berlin- Friedrichshagen, Halle an der Salle, Munich, Vienna, Budapest, Turin, Genoa, Paris, Sapporo, and Taipeh. To the curators of all of these we wish to express our appreciation. Their cooperation has permitted the use of first-hand information for most of the nomenclatural decisions. INTRODUCTION VII The drawings of generic characters were made by Mr. Kakuzo Yamazaki of Tokyo, through the cooperation of Captain Wallace P. Murdock. The drawings of specific characters are mostly by Miss Y. Morimoto, who worked under the direction of Dr. M. Tokunaga of Kyoto, Japan. Figure 284 is from drawings by Miss M. McKay of the Canadian Department of Agriculture, lent for inclusion in this paper. Photomicrographs of genitalia are by Mr. John Alley of the University of Michigan Photographic Services. The Scambus drawings in figures 310-312 were supplied by G. S. Walley and those of Delomerista in figures 313 and 316 by Luella Walkley. Mrs. Rosemary Frey and Miss Sharon Carey assisted with making the maps showing distribution. Typing was mostly by Mrs. Frey and Miss Ellen Linna. When this paper was begun, four other students of the Ichneu- monidae had already started on revisions of the genera Scambus, Delomerista, Poemenia, and Aplomerus; they have all agreed to include their work as parts of the entire revision, for the convenience of future students who would prefer a complete treatment, all under one cover. Although included in this revision and conforming with its style to some extent, these papers are independent contributions. Other parts of this publication are by Henry and Marjorie Townes, as joint authors, but those portions that validate new generic, specific, and subspecific names are the work of the senior author alone. Thus their authorship should be ‘“Townes’”’ rather than ‘‘Townes and Townes.” We make this statement to provide a shorter form for the citation of the author of the names. The same citation, “Townes,” is correct for all names in our previous papers, for the same reason. ae A ah a rie ae a gs | . De alin Te yy vethniae a ra , ; hi ihe i as a ay p hbiag Sythe ogh 2 Hug 43 ae aif: yet en ah 3 amit Het Cilia a ll nati! ¥ 4 ty , Pi was ots ss CEO: i ou Seal) ‘ TaEe welt fe ABD S an Ait " an ro ‘ e “u 4 Hels UE ak i ail 5 » 2 VES iy * Di ; } pi : tk ty bf) Ay, P oY ae etot ta." oily Rey) re a oe iy mien \ vipat ienart i 2. Subfamilies Ephialtinae Xoridinae Acaenitinae A ae ah Bt ae a GS a ay Subfamilies Ephialtinae, Xoridinae, and Acaenitinae Defined THE THREE SUBFAMILIES included in this bulletin were formerly all in one subfamily (Pimplinae) which was defined as having a rather elongate, cylindric body shape; areolet triangular or absent; sternaulus absent or weak and short; tarsal claws not visibly pectinate but often with an accessory tooth (especially in the female); first abdominal segment usually short and broad, with its spiracle at or in front of the midlength, and not strongly curved at the spiracle; and ovipositor almost always more than half as long as abdomen, without a subapical dorsal notch. The above definition will distinguish most of this group of species fiom the majority of other ichneumonids, but is not entirely adequate. No completely workable definition has yet been devised, and the student will need to rely on the habitus figures of the various genera for deciding doubtful cases of whether or not the specimen at hand belongs in the group treated here. Studies in the last 20 years have shown the desirability of sub- dividing the subfamily Pimplinae of authors, to arrive at more natural and more easily defined groups of genera. There has been a progres- sive narrowing of the limits of the ‘‘Pimplinae”’ by taking unrelated groups away from it, and in this paper we divide the remainder to make three subfamilies. Two of the resulting subfamilies (Ephial- tinae and Acaenitinae) are probably natural; the third (Xoridinae) may not stand as defined after further critical studies, but represents a plausible synthesis of present knowledge. It is close to the Gelinae. Conclusions on relationships which have led to the splitting of the Pimplinae are based on all information available, some of which cannot easily be conveyed in terms of definite characters. Some very important data are in larval morphology. Our information on larvae stems mostly from Beirne’s paper on ichneumonid larvae (Trans. Soc. Brit. Ent., vol. 7, pp. 123-190, 1941) and from a larger paper by Dr. J. R. T. Short (Proc. U.S. Nat. Mus., vol. 110, No. 3419, pp. 391-511, 64 figs., October 23, 1959). Dr. Short was kind enough to send us a manuscript copy of his paper, which has been extremely helpful in decisions on generic relationships. Such adult characters as can be stated definitely are given in the keys to the three subfamilies and in their descriptions. 3 4 U. S. NATIONAL MUSEUM BULLETIN 216 The subfamilies (formerly Pimplinae of authors) here included are separated by the following key: 1. Female subgenital plate very large, triangular, folded on the midline, its apex reaching or surpassing the apex of abdomen (figs. 308-310,a); apical third of abdomen of male compressed (deeper than wide) . 3. Acaenitinae (p. 544) Female subgenital plate not enlarged, or if rarely enlarged (as in Clistopyga) not triangular and folded on midline (figs. 285-307) ; apical third of abdomen of male cylindric or depressed (wider thandeep). . . . are aye te 22 2. First abdominal sternite more or less free from its tergite (and Poe first tergite with a glymma), and/or the propodeum not areolated; epipleura often narrow or vestigial, but sometimes wide... .1. Ephialtinae (p. 4) First abdominal sternite completely fused with its tergite (and the first tergite without a glymma); propodeum areolated; epipleura moderately wide to very owide! .:). 90 slsesiey nhs hlag- Tepe fan ayedcXhonidinae; (p..436) Subfamily Ephialtinae Ficures 284-304,a Front wing 2.5 to 30 mm. long; apical margin of clypeus typically thin and with a median notch that makes it bilobed, but often (as in Polysphinctini, Poemeniini, and Rhyssini) of other shapes; labrum hidden beneath clypeus and mandibles; propodeum with few or no areas bounded by carinae except in Xanthopimpla, some Polysphinc- tini, and the Theroniini; costula present only in some Xanthopimpla and Theronia; tarsal claws often with an accessory tooth or basal lobe, especially in female; first sternite usually free from its tergite, the tergite with a glymma when its sternite is free; epipleura moder- ately wide to very narrow or vestigial; apical third of abdomen usually depressed or cylindric but in some females (especially Rlhyssini) somewhat compressed; female subgenital plate usually transversely rectangular and weakly sclerotized, often with a median mem- branous area, never with a long median point. The larva of the Ephialtinae differs from that of all other ichneu- monids in having the sclerotic spur of the hypostoma and the stipital sclerome both well developed and reaching each other at their apices rather than the sclerotic spur reaching the stipital sclerome before its apex. The antenna is usually well developed and the mandible with teeth, but in the Ephialtini the antenna is vestigial and the mandible without teeth. This is the largest group of the subfamily ‘‘Pimplinae” of recent authors and contains many common, well known species. Though it appears to be a very primitive group the species and genera are still rapidly subdividing, which results in some taxonomically dif- ficult situations. The subfamily contains the genus Pimpla and might be called ICHNEUMON-FLIES, PART 2: EPHIALTINAE 5 “Pimplinae” rather than ‘Ephialtinae.’”? We have chosen the latter name because it is based on the oldest genus of the subfamily. With the adoption of the name Ephialtinae all the supergeneric group names in the Ichneumonidae will be based uniformly on the oldest included genus, or when there is more than one of the same age, on the one selected by the first revisor. Although the subfamily name Pimplinae is well known, which would make it desirable to continue using the name, in previous applications it has included a different group of insects than our subfamily Ephialtinae. The six tribes of the Ephialtinae are keyed out below. They are difficult to define and the beginner will have to use the key with care. The habitus figures of the Nearctic genera (figs. 284—304,a) should help in making correct tribal identifications. Key to the tribes of Ephialtinae 1. Mesoscutum covered with sharp transverse wrinkles (figs. 300,b, and 302,b— SOSA) fis: : BY Rsiqde Vat tod cigs) Veto eee mn Nesosouburt Without teauaveise euneies or sometimes with transverse wrinkles on only a small portion of its surface. . . . cre at Ta 2. First tergite with a sharp lateral longitudinal carina on its. spiracle to its apex (fig. 300,b); last tergite of female elongate but without a horny rim or truncate horn at apex (fig. 300,b) (Genus Pseudorhyssa) 4. Theroniini (in part, p. 350) First tergite without a distinct lateral longitudinal carina from its spiracle to the apex (figs. 302,b—304,a); last tergite of female elongate and ending in a heavy polished rim or a truncate horn (figs. 302,a—304,a) 6. Rhyssini (p. 395) 3. Prepectal carina absent (figs. 301 and 302,a); first tergite without a lateral longitudinal carina (at level of spiracle) except sometimes in Deuterozorides; upper part of temple with a scabrous area except in Poemenia (figs. 301,b and71S02!a)' hes). . . . . 5. Poemeniini (p. 375) Prepectal carina eeend exvebtli in Alp ahstonuns in Dolichomitus cuspidatus, and in a few extra-limital genera; first tergite usually with a lateral longi- tudinal carina; upper part of temple without ascabrous area. . .... 4 4. Mesopleural suture without a distinct angulation near the middle (figs. 298 and 299,a), or if there is an angulation (in the exotic genus Xanthopimpla) the tarsal claws each with an enlarged hair with a flattened tip and the apex of mandible twisted so that its lower tooth is toward the mouth; when hind tibia is banded there are apical and basal dark bands and a median pale band, the extreme base thus being dark . . 3. Ephialtini (p. 280) Mesopleural suture with a weak angulation near the middle (figs. 285-297; 299,b, and 300); never with both an enlarged hair on the tarsal claws and the apex of the mandible twisted; when hind tibia is banded there are usually apical and subbasal dark bands and median and basal pale bands, the extreme base thus being pale. . . . a 5 5. Tarsal claws of female without a basal tooth (ca: 299 4 and 300,a) | fercites 2 through 4 with fine indistinct punctures, Folened or strongly mat; areolet present; male subgenital plate often longer than wide. 4. Theroniini (in part, p. 350) 6 U. S. NATIONAL MUSEUM BULLETIN 216 Tarsal claws of female, or at least the front claws of female, with a basal tooth except in Perithous and in the European genus Hremochila (figs. 285,a— 297,b); tergites 2 through 4 usually with rather coarse, distinct punctures; areolet present or absent; male subgenital plate usually wider than long. . 6 6. Last segment of tarsus not enlarged, a little narrower than the basal segment of the tarsus (figs. 285,a-292,a); areolet present except in Zaglyptus, Clis- topyga, and some Tromatobia and Acropimpla; ovipositor of approximately uniform size between its middle and its apical point (figs. 285,a—-292,a), except in Clistopyga (fig. 291,a) ....... .- 1. Pimplini (p. 6) Last segment of tarsus enlarged, a little wider than the basal segment of the tarsus (figs. 292,b—297,b) ; areolet absent except in Laufeza; ovipositor tapered from near middle to its apical point (figs. 292,b—297,b). 2. Polysphinctini (p. 216) 1. Troe PiIMe ini FicurEs 285-—292,a Front wing 2.5 to 22 mm. long; clypeus usually a little convex basally and a little impressed or concave apically, with a median notch in its apical margin which gives it a bilobed apex, sometimes the clypeus more uniformly convex, truncate apically, or with a median apical tubercle; mesoscutum without transverse wrinkles, its notauli moderately strong, weak, or vestigial; prepectal carina present except in Alophosternum, in Dolichomitus cuspidatus, and in an un- named Neotropic genus; mesopleural suture with an angulation just above the middle; propodeum usually with its pleural carina complete, sometimes with apical part of lateral longitudinal carina preserved, and often with basal 0.4+ of median longitudinal carinae present, otherwise without carinae except that in Perithous the petiolar area may appear to be completely bounded by a carina; last segment of tarsus not enlarged, a little narrower than basitarsal segment; tarsal claws of male simple; tarsal claws of female with a large, basal, lobelike tooth (except in Perithous, on the hind claws of a Japanese species of Alophosternum, on the middle and hind claws of an un- named Oriental genus, and in the European Eremochila ruficollis) ; tarsal claws without an enlarged hair with a flattened tip; areolet present except in Zaglyptus, Clistopyga, and in some species of Tromatobia and Acropimpla; nervellus broken above, near, or below the middle, or sometimes not broken; first tergite free from its sternite except in an unnamed genus from the Orient, its lateral carina usually strong; subgenital plate of male transverse, its apex usually truncate or retuse, but in Perithous longer than wide and tapered to a blunt point; last tergite of female without an apical horn or boss; ovipositor usually moderately long to very long, rather slender, and of uniform diameter, but in Clistopyga short, upcurved, and tapered. The Pimplini are parasitic on hosts hidden within plant tissues or cocoons. ‘Their long ovipositors are used in reaching such _ hosts. ICHNEUMON-FLIES, PART 2: EPHIALTINAE 7 The larvae feed externally on the hosts and in correlation with this habit have rather large mandibles with serrate edges. The tribe is difficult to divide into satisfactory genera. It is one of those situations in which the careful taxonomist would prefer to withhold judgment until much more information is available. The position of indecision, however, should not be maintained too long and we have written down our best judgment for the present. We hope that it proves to be useful and to have resulted in progress in the right direction. The keys were devised for maximum ease of use and accuracy, but are not foolproof. Interpretation of some of the characters needs experience, and the question of where the nervellus is broken (couplet 7) will, in borderline or questionable cases, require a trial run through both halves of the couplet. Some exotic species will not conform to all key characters. The genera may be grouped into assemblages which to a large degree seem to correspond to their real relationships. These are discussed below. Pimpla group: Occipital carina complete, or rarely obsolete medi- ally; tarsal claws of female with a lobelike tooth (except in Eremo- chila) ; male subgenital plate not elongate. There are two subgroups: A. The Pimpla subgroup tends to have a prominent dip on the midline above the occipital carina, temples tend to be broad, clypeus flatter, subgenital plate of female usually with a large, median mem- branous area, upper valve of ovipositor usually not attenuate at apex, and ridges of basal teeth of lower valve of ovipositor moderately oblique to vertical. The genera are Exeristes, Eremochila, Scambus, Flavopimpla, Calliephialtes, Holcopimpla, Delaulax, Xanthephialtes, Xanthophenaxz, Pumpla, Apistephialtes, Anastelgis, Dolichomitus, Afre- phialtes, Mesoephialtes, Pimplaetus, and two undescribed genera. These genera are parasitic on larvae in plant tissues (buds, leaf rolls, stems, wood, etc.) and oviposition is through plant tissue to reach the host. B. The Tromatobia subgroup tends to lack the median dip in the occipital carina or to have only a weak dip, the temples usually narrower, clypeus more convex, subgenital plate of female usually completely sclerotized, upper valve of ovipositor usually with an attenuate point, and ridges of basal teeth of lower valve of ovipositor very oblique. The genera are Acropimpla, Sericopimpla, Cnemo- pympla, Iseropus, Tromatobia, Zaglyptus, and Clistopyga. These genera are parasitic on cocoons of various kinds, including spider egg cocoons, and oviposition is through silk to reach the host. Alophosternum group: Occipital carina absent medially above; mesoscutum covered with moderately dense hairs; tarsal claws of female with a basal tooth on the front claws, with or without a basal tooth on the middle and hind claws; male subgenital plate not elongate; basal half of ovipositor weakly decurved. Alophosternum 8 U. S. NATIONAL MUSEUM BULLETIN 216 and an undescribed genus from the Orient belong to this group. Alophosternum has been reared from leaf-mining larvae. Brachycentropsis group: Occipital carina absent above; meso- scutum covered with dense hairs; tarsal claws of female each with a basal tooth; propodeum behind with a large smooth area bordered by a carina; first tergite with strong, complete lateral longitudinal carina, its dorsal longitudinal carinae very short and weak; female subgenital plate heavily sclerotized; ovipositor relatively short, compressed, the apex of its lower valve with a dorsal lobe that encloses apex of upper valve. Brachycentropsis of the Mediterranean region is the only genus. Camptotypus group: Occipital carina absent above, often entirely absent; mesoscutum with few hairs or none, polished; tarsal claws of female with a large basal tooth; male subgenital plate not elongate; ovipositor straight. The genera of this group are tropical, Campto- typus in the Old World tropics and Zonopimpla, Odontopimpla, and four unnamed genera in the New World tropics. The host relations are not well known. Perithous group: Occipital carina complete, without a median dip; tarsal claws of female without a basal tooth; propodeum with its petiolar area bounded by a more or less distinct carina (bounded in a similar way in the Brachycentropsis group but in none of the others) ; male subgenital plate elongate, ending in a median point. Perithous is the only genus. It parasitizes the nests of aculeate Hymenoptera living in stems. Key to the Nearctic genera of Pimplini 1. Tarsal claws of female without a basal lobe (fig. 292,a); subgenital plate of male longer than wide, prolonged medially into a rounded point; abdomen of the Nearctic species black with a narrow white apical band on each GETDIte min, eerie wee piste io cee cu ih ene ieee: gee 14. Perithous (p. 209) Tarsal claws of female with a large basal lobe (at least in the Nearctic species) ; subgenital plate of male wider than long, usually without a median point; abdomen usually entirely black, rarely colored as above. ......... 2 2. Prepectal carina absent (fig. 291,b); occipital carina absent above; basal half of ovipositor down-curved (fig. 291,b)..... 13. Alophosternum (p. 206) Prepectal carina present except in Dolichomitus cuspidatus (figs. 285-291,a) ; occipital carina nearly always present above; basal half of ovipositor stralgay (figs 250-20 T Ayres Mt. sales UVa ce lokee aa aoe 5 ems 3 3. Occipital carina not dipped downward at the midline, always strong medially; areolet often absent; frontal orbits often marked with white. (Parasites OL SINACH CPCS Nias cctan =: x eres s bretgactecl bas