A new species in the Simulium vernum group from the Northern Limestone Alps of Austria: Simulium hasekei (Diptera: Simuliidae).

Simulium hasekei new species is described from the Alps of Austria. It is characterized by a broad trapezoidal ventral plate in the male, long straight arms of the genital fork in the female, a well-developed anterodorsal projection on the weakly woven cocoon, and a deep rounded postgenal cleft and strong paralateral hypostomal teeth in the larva. The species is chromosomally most similar to the Holarctic S. bicorne Dorogostaisky, Rubtsov Vlasenko and S. fontinale Radzivilovskaya and the Nearctic S. craigi Adler Currie. It is known from one small ponor brook, in association with S. aureum (Fries) s. s., S. beltukovae (Rubtsov), and Simulium vernum Macquart s. s.