抄録
Sexual mosaics were found in eight adult Japanese blackflies, i.e., two Simulium arakawae Matsumura, 1921, four S. bidentatum (Shiraki, 1935), all collected from cattle sheds while biting, and two S. aokii (Takahasi, 1941) which emerged from pupae. They were distinguished into three types, i.e., bilateral, antero-posterior and other types of gynandromorph.
