The Study of B Chromosomes In Drosophila albomicans Ⅰ. The Number and Frequency of Bs In Kunming Population

In this study,mitotic metaphase of Drososphila albomicans with B-chromosomes 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.