Abstract
Morphological characters of Simulium konoi (Takahasi) so far assigned to the subgenus Simulium (Nevermannia) are revised based on female, male, pupal and larval specimens collected from Tottori (type locality), Oita and Ibaraki, Japan. There was no difference in most morphological characters among the different populations. Simulium konoi is transferred to a Holarctic subgenus Simulium (Boreosimulium), because it has a combination of the subgeneric key characters including arms of furcasternum without any projection directing ventrally, slender male style tapered to pointed apex, paramere with several hooks, and the larval antenna with 3-5 colorless annular bands. This species is easily distinguished from all the 16 known species of the subgenus Boreosimulium by the female cibarium with several oblique rows of denticles, an autoapomorphic character not found so far in other species of Simuliidae.
