Genus Condylostylus Bigot, 1859

Condylostylus is the second largest genus in Sciapodinae, with a high diversity in the Neotropical region, where 70% of the species occur (Bickel 1994). Though the genus includes over 250 species, only eight species are recorded in the Himalayas region, of which 2 pairs of species are suggested to be synonyms. Condylostylus conspectus Becker and C. caii Parent were examined by Bickel (1994) who suggested the species to be very similar and probably conspecific. No additional C. caii have been reported since Bickel (1994) and the differences between the two species mentioned by Parent (1934) are actually not sound based on our inspection of C. conspectus . We agree with Bickel’s assessment that they are possibly synonyms; however, we do not make the decision since we have not studied the type specimens.

Condylostylus nebulosus Becker and C. luteicoxa Parent only differ in the mid tarsus and the description by Parent has some discrepancies with the holotype, which led Bickel (1994) and Yang et al. (2011) to suggest that they belong to the same species. But here they are still treated as separate species because the holotypes have not been examined and there are differences in the descriptions. Similar to Chrysosoma, Nyingchi is the only region in Tibet we collected Condylostylus .

Species of this genus can be distinguished by the following features: Head: frons with 1 strong vt arising from strongly raised tubercle on frons in both sexes; face sometimes bulging beneath antenna; male clypeus broad and close to eye margin; arista-like stylus usually dorsal. Thorax usually with 2–3 pairs of long acr, 5 strong dc; strong lateral and median sc. Legs: Fore coxa with 3 strong black distolateral bristles; fore tibia usually without strong bristles; TII with obvious ad and pd; male usually with crocheted hairs on basal half of mid tibia and tarsus; hind tarsus sometimes with flattened pad-like tarsomeres. Wing often with dark brown bands, sometimes with enclosed window on crossvein dm-cu. M 1 characteristically with sharp, almost right angle bend at branch with M 2; crossvein dm-cu usually straight, sometimes slightly sinuate. Abdomen: Tergum VII well developed, sternum VII strongly reduced, membranous; hypopygium often relatively small compared with other Sciapodinae, and basally encapsulated within segment VII; hypandrium often short and broad, lateral arm of hypandrium reduced or absent; cercus usually simple, commonly elongate and filamentous, seldom clavate and expanded (Bickel 1994; Yang et al. 2011).

A key to Condylostylus from the Himalayan region is provided. Condylostylus albifrons Parent is not included because this species record in based only on female specimens.