A New Species of Diopsis L. (Diptera: Diopsidae) from South Africa and Swaziland, and Brief Review of African Species with a Large Apical Wing Spot

Diopsis stuckenbergi Feijen & Feijen, sp. n. is described and illustrated from South Africa and Swaziland. This species belongs to the D. cruciata-group, one of three African Diopsis species-groups with a large apical wing spot. Diopsis stuckenbergi sp. n. is closely related to D. eisentrauti Lindner and this latter species is redescribed. A T-shaped pruinose cross is always evident on the scutum of D. eisentrauti, but in many specimens of D. stuckenbergi sp. n. the central section of the T-cross is absent. The two species form a subgroup within the D. cruciata-group. All species of the African species-groups with apical wing spots are briefly reviewed. Diopsis fumipennis Westwood, 1873 is proposed as a junior synonym of D. atricapilla Guérin-Méneville, 1835. Data are presented on sexual dimorphism with respect to eye span in D. stuckenbergi sp. n. and D. eisentrauti.