Dolichopodidae (Diptera) from Papua New Guinea XV. Scepastopyga gen. nov. and the establishment of a new subfamily,the Achalcinae

The new genus Scepastopyga is described with S. semiflava sp. nov. as type species. Mouthparts and genitalia of Scepastopyga and Achalcus have been studied. General body structure and the anatomy of the mouthparts and genitalia showed that Scepastopyga is closely related to Achalcus and Xanthina. The 3 genera are grouped into the new subfamily Achalcinae, an ancestral group close to Medeterinae and Sciapodinae, having most affinities with ancestral Medeterinae.