Key to adults of Mongolian Astegistidae

1 Genital and anal apertures small, situated far from each other; notogastral setae short.............................. 2

- Genital and anal apertures large, situated close to each other; notogastral setae long .................................. ............................................................................................................. Astegistes pilosus (C.L. Koch, 1840)

2 Genital plates with five pairs of setae; interlamellar setae smooth, not reaching the tip of rostrum; median teeth of lamellar cusps well developed ....................................................................................................... 3

- Genital plates with six pairs of setae; interlamellar setae barbed, reaching the tip of rostrum; median teeth of lamellar cusps mostly absent, rarely poorly developed .......................... Cultroribula taigagica sp. nov.

3 Rostrum with nine teeth, among them three central teeth large, much larger than lateral teeth; interlamellar setae about half as long as lamellar setae ....................................... Cultroribula vtorovi Krivolutsky, 1971

- Rostrum with 17 teeth, among them a central tooth slightly larger than lateral teeth; interlamellar setae nearly as long as lamellar setae ......................................................... Cultroribula dentata Willmann, 1950