[Anopheles maculipennis northeastern and Anopheles beklemishevi southwestern distribution areas' borders]

Distribution of An. maculipennis and An. beklemishevi in the Upper Volga area was investigated. Species discrimination was based on the study of polytene chromosomes. The examined material included about 2000 larva and imago from 11 localities, namely: Andropov, Yaroslavl, Rostov (Yaroslavl.), Solnechnogorsk, Protvino (Moscow region), Suzdal, Murom (two localities), Joshkar-Ola, Zelenodolsk, Kujbyshev. It appears to be a 700 X 200 km intergradation zone between the species distribution areas.