SUMMARYQuinacrine-bright bands of polytene chromosomes have been localized in the members of the virilis group. Four species: Drosophila virilis, D. lummei, D. flavomontana and D. ovivororum have Q-bands of varying intensities. D. virilis, the most karyotypically primitive member of the group, has a Q-band doublet in the heterochromatin of chromosome four. This doublet is not found in any of the other members of the group. One species, D. flavomontana, is polymorphic for a Q-band in the Yi-j region of chromosome four. With the exception of D. ezoana, chromocentric quinacrine-bright granules are a unifying feature of all the members of the virilis group.