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Lathrolestes Foerster, 1869: 196. Type species: Tryphon clypeatus Zetterstedt. By subsequent designation of Viereck (1912: 176) (as type species of Lathrolestus).

Laphyroscopus Foerster, 1869: 197. Type species: Tryphon gorskii Ratzeburg [a junior subjective synonym of Lathrolestes luteolator (Gravenhorst)]. By subsequent designation of Viereck (1914: 87) (as type species of Luphyroscopus). Synonymized by Perkins (1962).

Homalomma Foerster, 1869: 198. Type species: Homalomma caliroae Rohwer. By subsequent inclusion and designation of Rohwer (1915: 218). Synonymized by Townes (1945: 502).

Ecclinops Foerster, 1869: 201. Type species: Tryphon orbitalis Gravenhorst. By subsequent designation of Viereck (1914: 49). Synonymized by Townes (1945: 502).

Camporychus Foerster, 1869: 208. Type species: Lathrolestus marginatus Thomson. By subsequent designation of Townes (1970: 99). Synonymized by Townes (1970: 99).

Luphyroscopus Thomson, 1883: 915. Unjustified emendation.

Lathrolestus Thomson, 1883: 916. Unjustified emendation.

Tryphonopsis Brauns, 1898: 62. Type species: Tryphonopsis ensator Brauns. Monobasic. Synonymized by Roman (1910).

Ritzembosia Smits van Burgst, 1912: 260. Type species: Ritzembosia meridionalis Smits van Burgst. Monobasic. Synonymized by Townes (1970: 100).

Culmina Benoit, 1955: 32. Type species: Culmina ruwenzorica Benoit. Original designation. Synonymized by Townes (1970: 100).

There are more than 70 valid species as of 2011 (Yu et al. 2005, Reshchikov et al. 2010, Reshchikov 2010, Reshchikov 2011a, 2011b).

The genus description above is based primarily on Nearctic specimens representing about 20 species.

Foerster described 489 genera with no included species (Perkins 1962). The designation of type species for Foerster’s genera has been complicated by what are now generally accepted (see Perkins 1962) as unjustified emendations of Foerster’s names by Thomson. Viereck, for example, designated different type species for both Lathrolestes Foerster (Viereck 1914) and Lathrolestus Thomson (Viereck 1912), undoubtedly because the species included by Thomson (1883) in Lathrolestus were not the same as the nominal species first included under the name Lathrolestes by Davis (1897). A similar situation applies to of type species for Laphyroscopus Foerster and Luphyroscopus Thomson, because the sole species first included by Davis in Laphyroscopus was not among the three species included by Thomson (1883) in Luphyroscopus. Thus, with the treatment of Luphyroscopus as an unjustified emendation of Laphyroscopus, the type species becomes that designated by Viereck (1914) from among those included by Thomson in Luphyroscopus rather than the species first included under the name Laphyroscopus by Davis. Townes (1945) and Townes and Townes (1951) initially followed the type designations and listings by Viereck (1914), but subsequently Townes (1969) accepted Thomson’s names as unjustified emendations. This confused state of affairs has produced a number of minor nomenclatural oddities: Perkins (1962), for example, appears to be the first to include the name Laphyroscopus as a synonym of Lathrolestes since Townes (1945) and Townes and Townes (1951)) kept the two as valid genera while treating Luphyroscopus Lathrolestus as a synonyms of Lathrolestes. Of more importance, however, is the significance of a correct understanding of the various type species to any subsequent work on the classification of what is currently the largest genus of Perilissini.

A few species of Lathrolestes may be readily distinguished from nearly all other perilissines by the absence of the occipital carina middorsally. Several species of Lathrolestes also have long ovipositors relative to most other perilissines and most Lathrolestes have the subapical notch of the ovipositor weak to virtually absent.

Burks (1952)

differentiated Lathrolestes from Perilissus and two other perilissine genera on the basis of the separation of the occipital and hypostomal carinae ventrally, with the two carinae not joined before reaching the base of the mandible in Lathrolestes. Townes (1970) also used this character for segregating Lathrolestes from most other perilissine genera and Barron (1994) largely followed Burks and Townes, but noted exceptions for a few species. Gauld (1997), however, in his revision of Costa Rican ctenopelmatines, separated Lathrolestes from Perilissus on the basis of the shape and sculpture of the first metasomal tergite (T1), and stated that the arrangement of the hypostomal and occipital carinae was the same in the two genera. Since the shape and sculpture of T1 is rather homoplastic among perilissines, support for the monophyly of Lathrolesthes is thus lacking and will ultimately need to be addressed. In this regard, Barron (1994) provides some characters useful for recognizing species groups and these should facilitate the delimitation of smaller, monophyletic units.

Clypeus (Figs 4-6) with ventral margin blunt, thick to very thick; without small lateral tooth or projection; ventral margin mostly convex to truncate, more rarely concave medially; epistomal sulcus often sharply distinct throughout, with clypeus in profile angled outwardly from face (Fig. 6), epistomal sulcus more rarely weakly indicated, with clypeus nearly in same plane as face. Malar space nearly always short but distinct, often less than half basal width of mandible. Mandible (Fig. 4) with ventral tooth much longer than dorsal tooth. Ocelli small, lateral ocellus distinctly shorter than distance between ocellus and eye. Maxillary palp not exceptionally long, usually about equal to height of head, shorter than height of head in a few species; female antennae shorter than or about as long as body, rarely distinctly longer; first flagellomere with small tyloid (Fig. 5) containing 15 or fewer sensilla. Hypostomal carina (Figs 7, 8) either widely separated from occipital carina ventrally or joining occipital carina at base of mandible; occipital carina either complete (Fig. 7) or, more rarely absent (Fig. 8) middorsally. Dorsal end of epicnemial carina distant from anterior margin of mesopleuron in most species, though approaching margin in some species. Notaulus varying from absent to very weakly impressed anteriorly in many species, but short and sharply impressed in a few species. Clearly-defined u-shaped notch absent between propodeum and metanotum in lateral view; pleural carina complete, well-developed; propodeal carinae varying from well-developed and complete (Fig. 10), with hexagonal to pentagonal areola in a few species to strongly reduced to just a petiolar area posteriorly in a few species; most species with complete posterior transverse carina and traces of longitudinal carinae and areola. Apex of mid tibia with small tooth similar to that of fore tibia in at least some species, apical rim more evenly rounded in others; apex of hind tibia with well-developed comb in some species, but comb more often poorly developed; posterior hind tibial spur usually at least 7x longer than maximum width at base but in a few species (< 10%) relatively short, somewhat triangular, at most 4X longer than maximum width near base; tarsal claws completely pectinate in most species, but with pectination confined to basal 0.5 in some species. Fore wing areolet (Fig. 9) nearly always present; stigma short and broad in many species, Rs+2r arising near middle of stigma. Hind wing with first abscissa of CU1 usually about equal in length to 1cu-a, sometimes distinctly longer, more rarely distinctly shorter. T1 sometimes long and slender , but often distinctly broadening posteriorly; sometimes with rounded or more rarely sharply carinate dorsal carinae; without distinct basal depression at dorsal tendon attachment in most species; dorsal-lateral carina extending from spiracle to apex of T1 in nearly all species, weak or absent in some males; glymmae (Fig. 11) on each side meeting on the midline posterior to dorsal tendon attachment, large, deep, separated at midline by translucent partition. T2 thyridium absent; laterotergites of T2 and T3 completely separated by creases. Ovipositor (variation illustrated in Figs 13-17) straight (except in aquilus), relatively broad at base in some species, relatively narrow throughout in others, rarely with distinct subapical notch (e. g. a small but sharply delineated notch present in aquilus), usually with the ovipositor valves deep and accompanied by a broad and very shallow notch, or with the valves tapered to a point and the notch indistinct; ovipositor usually fairly long, as in most Perilissus and Trematopygodes, but sometimes even longer; ovipositor sheath usually long and slender, broadly rounded at apex, but curved in aquilus. Male parameres mostly broadly rounded or rectangular in dorsal view, not strongly attentuate distally; aedeagus rounded and clubbed distally.

This is a large genus with most of the described species from the Holarctic Region. There are fewer species thus far described from the Neotropical, Oriental, and Ethiopian regions.

Barron (1994) provides host information for Nearctic species. Additional information can be found in Yu et al. (2005). In addition to tenthredinid hosts, there are a few confirmed records from leaf-mining Lepidoptera. Some of the species attack tenthredinid forest pests and a few of these have been used in biological control (Quednau and Guevremont (1975), Barron 1994, Reshchikov et al. 2010).

This page was assembled by Bob Wharton as part of a larger collaborative effort on the genera of Ctenopelmatinae. This work would not have been possible without the groundwork provided by Ian Gauld’s study of the Australian and Costa Rican faunas, and we are particularly grateful for his assistance in many aspects of this study. We also thank David Wahl for useful feedback throughout our study, to Gavin Broad for exchange of information on Perilissini, and to Alexey Reschikov for exchange of information on Lathrolestes. Matt Yoder provided considerable assistance with databasing issues, and our use of PURLs (http://purl.oclc.org) in this regard follows the example of their use in publications by Norm Johnson. Andrea Walker, Amanda Ladigo, Heather Cummins, Caitlin Nessner, and Cheryl Hyde graciously assisted with image capture, processing, formatting and literature retrieval. This study was supported by the National Science Foundation’s PEET program under Grant No. DEB 0328922 and associated REU supplement nos DEB 0723663, 0923134, and 1026618. Page last updated February, 2011.

This material is based upon work supported by the National Science Foundation under Grant Number DEB 0328922 with REU supplements DEB 0723663, 0923134, and 1026618.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.