[Comparative karyological study of 2 close species of blackflies of the genus Eusimulium].

The structure of polytene chromosomes in the salivary gland of two hard for distinguishing species Eusimulium montium Rubz. and E. gviletense alizadei Djaf. was studied. The comparative-karyologic analysis of the taxons showed many common features in their karyotypes: complete conjugation of the homologous chromosomes in the connection between the length and the arms of chromosomes. At the same time these species are well distinguished karyologically according to the two inversions of the homozigotic type in the chromosomes I and III, to the duplication in IIL, and to the deficiency of the telometric region in IIIL of E. montium. These readjustments are considered to be secondary which suggests E. gviletense alizadei to be phylogenetically older than E. montium.