CHIRONOMUS OBENSIS SP-N (CHIRONOMIDAE, DI PTERA) FROM THE LOWER OB RIVER REGION

Male, and female image, pupa, larvae and karyotype of the new species Chironomus obensis sp. n. are described. Male image is distinctly iden tifiable by the finger-like hill on the gonocoxite, female one is iden tified by the sclerite form of X tergite and laterosternite, pupa - by the form of aspine in the back corner of VIII tergite, larva - by the menthum structure, 2n = 8, Combination of chromosome arms AB, CD, EF, G (cytocomplex thummi). Centromere area are not morphologically expre ssed. Nucleolar organizer and one Balbiany ring are located in the arm G. Microinversion is found in the arm A in the 85% of the larvae.