Abstract
A new blackfly species, Simulium (Gomphostilbia) hiroshii sp. nov. is described based on female, male, pupal and larval specimens collected from the Solomon Islands, South Pacific. This species possesses several characters which are unusual for the subgenus Gomphostilbia as follows : in adults, basal part of the radius fully haired in the female but bare in the male, female frons almost bare and shiny, female tergites 5-8 shiny, male genitalia lacking parameral hooks; in the pupal stage, 4 respiratory filaments per side, sterna 6 and 7 devoid of outer hook on each side; larval hypostomium with serrate lateral margins, and larval body with a large conical protuberance dorsomedially on abdominal segment 7, as well as paired dorsolateral small protuberances on abdominal segments 1-4 and metathoracic segment. This is a first record of the subgenus Gomphostilbia from the Solomon Islands and represents the most easterly geographical distribution of the subgenus.
