|New data on biology of the flies of the family Mydaidae (Diptera, Brachycera)|
|biology, Eremomidas, Leptomydinae, Mydidae, Palaearctic, Perissocerus, Rhopaliinae|
Data are given on the ecology and morphology of the larvae of Erenomydas bek Sem. and Perissocerus transcaspicus Portsch., which are morphologically strongly distinct from all described larvae of the genus Mydas Fabr. Larvae of E. bek Sem. develop in anchored and hemianchored hilly sands with Haloxylon. Larvae of P. transcaspicus Portsch. inhabit sand-hills practically uncovered by vegetation.