Immatures of Rheocricotopus (Psilocricotopus) valgus Chaudhuri and Sinharay of Darjeeling Himalaya with notes on ecology (Diptera: Chironomidae)

Abstract

The immatures (larva and pupa) of Rheocricotopus (Psilocricotopus) valgus Chaudhuri and Sinharay are described for the first time. The species belongs to chalybeatus group. The larva is oppurtunistic, present in the fast-flowing streams to slow-flowing organically enriched sewage drains. It lives in tunnels made of various particles glued together by silky secretions. There are two generations a year with peak emergence in April-May and September-November. The sex ratio of females to males is 2:1.