[B-chromosomes in the spermatogenesis of blood-sucking black flies].

The karyofund of Odagmia ornata taken from natural population was investigated with the light microscope, the existence of a definite number of specimens with B-chromosomes being discovered. The behaviour of B-chromosomes in the spermatogenesis was analyzed. The dynamics of the number of specimens with B-chromosomes is presumably associated with the peculiarities of their behaviour in meiosis, i.e. with the unequal distribution of these chromosomes in the number of sex cells.