A new species and new records of black flies (diptera: simuliidae) from Thailand.

Simulium (Byssodon) siripoomense sp. nov. is described based on two mature larval specimens collected from Thailand. This species is distinguished from the other known species of this subgenus by the pupal gill histoblast with six slender filaments. Four other simuliid species are newly recorded from this country : i.e., S. (Gomphostilbia) decuplum Takaoka and Davies, S. (G.) parahiyangum Takaoka and Sigit, S. (Simulium) brevipar Takaoka and Davies, and S. (S.) quinquestriatum (Shiraki). Two known species, which had been tentatively identified as S. (S.) sakishimaense Takaoka and S. (S.) nitidithorax Puri, are treated to be conspecific to S. (S.) fenestratum Edwards and S. (S.) tani Takaoka and Davies, respectively. Simulium (G.) sp. C, one of the five unnamed species previously reported, is found to conform to S. (G.) asakoae Takaoka and Davies.