Key to adult males of Asian Conochironomus

1. Wing vein R4+5 with, at most, 1 subapical seta................................... C. tobaterdecimus (Kikuchi & Sasa)

- Wing vein R4+5 with>10 setae........................................................................... 2

2 Humeral area with 1–2 isolated setae (anterior dorsocentrals). Hypopygium as in Fig. 2 B, 3C,D........ C. sawngthai sp. n.

- Humeral area bare. Hyopygium differs (e.g. Fig. 2 A, 3A,B).................................................... 3

3 Superior volsella base more-or-less rectangular, with digitiform projection crossing median margin and directed postero- mesally............................................................................... ‘E.’ effusus Dutta

- Superior volsella base ovo-cuneate with gently convex inner and posterior margins, with digitiform projection crossing poste- rior margin, curved mesally............................................................... C. nuengthai sp. n.