Species makeup and ecological characteristics of the black flies (Simuliidae) in the region of the Baikal-Amur mainline construction

18 species of black flies were registered from the north of the Amur district. It was found that the eternal frost affects considerably the species composition, abundance and phenology of black flies in this region. Prosimulium isio, Gnus cholodkovskii, G. rostratum and Sch?nbaueria subpusilla are bloodsucking species; of them G. cholodkovskii is most abundant. Data are given on the breeding places of bloodsuckers and seasonal dynamics of their flight.