Drosophila melanogaster, D. simulans, and D. sechellia are closely related species which belong to the D. melanogaster complex; the first two cosmopolita and the last one restricted to th Seychelles archipelago. The phenogenetical relationship between this complex and their hybrids were investigated by the comparison of sex-comb tooth number an genital arch of male. In interspecific hybrids of all crosses between three species four hybrid males were produced and completely sterile. Males of D. simulans (${O}_{9}$) have significantly less sex-comb teeth (mean 8.35) than either D. melanogaster (OR, mean 10.73) and D. sechellia (Ja, mean 10.60). From the analysis by the number of sex-comb tooth in interspecific hybrids we could not represent the direction of heredity nature. each species of D. melanogaster complex were characteristic in the shape of the genital arch, which readily allows these species to be distinguished. The common structure of the genital arch in the interspecific hybrids were mosaic-like structure between parental species.