This paper is an addition to the review of mosquitoes (Fauna of the USSR, vol. 3, issue 4) published in 1970. It describes mosquitoes, imagoes and larvae, found in the USSR by the authors and other specialists in 1971-1978. Most of these new species belong to the vast genus Aedes. A new key has been composed for identification of all the 60 species of this genus found in the USSR: a) by external characters, b) by structure of male genitals, c) by IV instar larvae. Number of mosquito species (family Culicidae) in the fauna of the Soviet Union is over one hundred at present, including several doubtful species.