A New Black Fly Species of Simulium (Gomphostilbia) (Diptera: Simuliidae) From Laos

Simulium (Gomphostilbia) laosense sp. nov. is described based on adults, pupae, and mature larvae from Laos. This new species is placed in the Simulium batoense species-group of the subgenus Gomphostilbia Enderlein. It is characterized by the pupal gill with eight filaments arranged as 3 + 3 + 2 from dorsal to ventral, of which an inner filament of the ventral pair is slightly longer than its counter filament, and is 1.7-1.8 times as long as filaments of the middle triplet. Taxonomic notes are provided to distinguish this new species from Simulium (G.) johorense Takaoka, Sofian-Azirun & Ya'cob from Peninsular Malaysia and four other related species. The phylogenetic position of this new species in the S. batoense species-group is also presented based on the mitochondrial COI gene. This new species represents the second species known from Laos.