68 XJ. S. NATIONAL MUSEUM BULLETIN 209 



Cryptochilus Rafinesque, 1815, Analyse de la nature . . . , p. 125 (Emendation), 

 ^(ionia Billberg, 1820, Enumeratioinsectorum . . . , p. 10l[(New name for SaZws). 

 Stenoclavelia Arnold, 1932, Ann. Transvaal Mus., vol. 15, p. 44, Type: Steno- 



clavelia mirabilis Arnold; original designation. 

 Chilochares Banks, 1941, Canadian Ent., vol. 73, pp. 119, 120. Type: {Crypto- 



cheilus hirkmanni Banks) = idoneum birkmanni Banks; original designation. 

 Adirostes Banks, 1946, Bull. Mus. Comp. Zool., vol. 96, p. 465. Type: Adirostes 



iolteca Banks; original designation. 



Medium sized species, or sometimes rather large, of average stout- 

 ness, the Nearctic species with forewing 6 to 14 mm. long; clypeus 

 medium or rather large, convex; pronotum moderately long, its hind 

 margin arcuate or somewhat angled at the middle; second inter- 

 cubital vein straight or somewhat curved; second recurrent vein 

 reaching the second cubital cell near or somewhat beyond its middle ; 

 cubital vein reaching wing margin; base of first discoidal cell without 

 a distinct irregularity in the membrane; nervulus beyond basal vein 

 by about 0.25 to 0.5 its length; nervellus ending basad of juncture of 

 cubitella with discoidella; anal lobe about 0.65 as long as submediella 

 (pi. 1, fig. 6); hind tibia with a dorsal serration, weaker in the male; 

 brush on inner side of hind tibia in the Nearctic species rather narrow 

 and with a subapical interruption; under side of hind tarsus of male 

 with a close fringe of hairs extending from its base to beyond the middle 

 (this fringe is absent in all other Nearctic Pepsinae except Priocne- 

 mioides.); last tarsal segment with two regular rows of bristles beneath; 

 tooth on tarsal claws erect, acute. 



The Nearctic species of Cryptocheilus are all closely related. In 

 the Old World the genus is very much larger and with a structural 

 diversity that poses problems in generic distinctions from other 

 complexes of species. The males of certain Old World species have 

 the thorax, especially the pronotum, elongate. The name Stenoclavelia 

 was proposed for such males. 



Keys to the Nearctic species of Cryptocheilus 



MALES 



1. Flagellum entirely orange, or its basal segment partly fuscous; body pubescence 



dark gray; wings largely orange 2 



Flagellum entirely blackish; body pubescence blackish 3 



2. Median apical notch on sixth sternite about 0.5 as deep as wide; apical margin 



of clypeus weakly concave; subgenital plate rather short. 



3. pallidipenne (Banks) 

 Median apical notch on sixth sternite about 1.2 as deep as wide; apical mar- 

 gin of clypeus weakly convex; subgenital plate elongate. 



4. attenuatum Banks 



