THE STUDY OF B CHROMOSOMES IN Drosophila albomicans 1. THE NUMBER AND FREQUENCY OF Bs IN KUNMING POPULATION
银额果蝇的B染色体研究：1.昆明群体的Bs数目和频率

In this study, mitotic metaphase of Drosophila albomicans with B-chro-mosomes were found in Kunming population. Their frequency of presence of B-chromosomes were 69.1%. At present, among D. albomicans has been studied from several localities, the frequency of B-chromosomes of Kunming population were the hightest. The number of B-chromosomes varied from 1 to 6 and differed between each iso-femals line of them as well as that of between individuals and cells. All the B-chromosomes were the smallest, dot-shaped of the karyotype. Both C-band and G-band staining are positive for B-chromosomes.