抄録
1. Eight wild strains in race A or C of Drosophila auraria were compared with regard to their sternite bristles of males. Generally, the members of the race A show the mean numbers of bristle higher than that of the race C, but the degree of the variation is higher in the latter than in the former. Therefore by this character alone, classification of specimens to a certain race is impossible.
2. Bristle numbers of F1 and F2 hybrids between the races, A and B were compared. The mode of fluctuation of the bristle count in F1 was somewhat intermediate between those of the parents. The distribution of the bristle numbers of F2 was broader than both the parents and the F1. The bristles of the sixth sternite of the males is proved to be polygenic.
