Abstract
The fauna and distribution of blackflies in Osaka Prefecture were investigated from various streams by sampling immatures at 24 sites in March 1987. A total of 835 larvae and 105 pupae belonging to 2 genera and 18 species were collected at 16 sites. Seven species, Simulium (Eusimulium) aureum, S. (E.) konoi, S. (E.) mie, S. (E.) subcostatum, S. (Simulium) kawamurae, S. (S.) quinquestriatum and S. (S.) rufibasis, were newly recorded from Osaka Prefecture, of which S. (E.) aureum was the new record from Japan. The predominant species was S. (E.) uchidai (29.9%), followed by S. (E.) subcostatum (16.2%) and S. (E.) mie (13.2%). The most widely distributed species was S. (E.) uchidai, followed by S. (E.) subcostatum and S. (S.) japonicum.
