Abstract
1. The emerging behavior as a daily rhythmic activity somewhat differ between Drosophila virilis and D. melanogaster. While the number of emerging individuals during 5-8 hours exceeds 50% of the total in the former, it remains always between 20 and 30% in the latter (Tables 1, 2).
2. In D. virilis, no fundamental differences in emerging activity exist between the wild race and the w-race. However, the st-race acts somewhat differently, showing large percentage of emerging individuals during 11-14 hours (Table 1). Cross-experiments, wild×st and st×w, show that this character of st-race behaves as recessive to that of wild race, in accordance with the morphological expression of eye colors in these two races (Tables 3, 4 and 5).
3. In D. melanogaster, no remarkable differences can be found out in the emergense activity between the wild race on the one hand and the w-, st-, vg-and dp-race on the other. However, the se-race behaves somewhat characteristically, i. e., the number of individuals emerging during 2-5 hours is far smaller and that emerging during 11-14 hours is fairly larger than in other races. Cross-experiment, wild×se, shows that this character of the se-mutant behaves rather as dominant to that of the wild race, in spite of recessive nature of se-gene as a determinant of the external morphological expression of eye color (Tables 6, 7 and 8). Flies (wild race) that emerging during 5-8 hours (A series) and 14-23 hours (B series) were successively selected covering 12 generations, but no remarkable differences in the modes of emergence were observed in both series.
