In larvae of Gnus corbis and Archesimulium vulgare, the number of rays of premandibles is 1.5–2 times less than in Metac-nephia kiryanovae, but greater than in Helodon alpes-tris and Prosimulium pecticrassum. Imago of Gnus cor-bis and Archesimulium vulgare belong to bloodsuckers and often attack humans in search of blood.