Microstylum vespertilio Engel, 1932 is redescribed from the Northern Cape Province of South Africa and transferred to Daspletis Loew, 1858, a genus closely related to Microstylum Macquart, 1838, that now incorporates eight southern African species. Knowledge of the species is updated and a new identification key is provided.

In revising the taxonomy of Acnephalum Macquart, 1838 it was discovered that the Afrotropical species are not congeneric when compared with the Palaearctic type species (A. olivierii Macquart, 1838 from Greece), which is congeneric with species of Pycnopogon Loew, 1847. As a consequence all Palaearctic Pycnopogon species are transferred to Acnephalum which takes precedence over Pycnopogon. In addition it was found that Sporadothrix Hermann, 1907, a genus previously synonymised with Acnephalum, is worthy of full generic reinstatement. The new genus Acnephalomyia is provided for Afrotropical species previously assigned to Acnephalum. The following taxonomic adjustments, innovations and decisions are introduced in this paper: New combinations: Species transferred from Pycnopogon - Acnephalum apicalis (Matsumura, 1916), Acnephalum apiformis (Macquart, 1849), Acnephalum denudatus (Séguy, 1949), Acnephalum fasciculatus (Loew, 1847), Acnephalum hirsutus (Becker, 1913), Acnephalum laniger (Dufour, 1833), Acnephalum leucostomus (Engel, 1939), Acnephalum melanostomus (Loew, 1874), Acnephalum mixtus (Loew, 1847), Acnephalum nikkoensis (Matsumura, 1916), Acnephalum pallidipennis (Brullé, 1936). Species transferred from Acnephalum - Acnephalomyia andrenoides (Wiedemann, 1828); Acnephalomyia dorsalis (Macquart, 1838); Acnephalomyia platygaster (Loew, 1858); Afroholopogon futilis (Wulp, 1899). New synonyms: Dasypogon quadratus Wiedemann, 1828, Acnephalum punctipennis Macquart, 1855, Acnephalum cockerelli Curran, 1934 and Sisyrnodytes sericeus Oldroyd, 1974 = Acnephalomyia andrenoides (Wiedemann, 1828); Acnephalum cylindricum Oldroyd, 1974 = Sporadothrix gracilis Hermann, 1907. New genera: Acnephalomyia (Type species: Dasypogon andrenoides Wiedemann, 1828), Astiptomyia (Type species: Astiptomyia bikos sp. n.). New species: Acnephalomyia eremia (Namibia), Acnephalomyia iota (Namibia, South Africa), Acnephalomyia leukoros (South Africa), Acnephalomyia probolos (South Africa), Ammodaimon platythrix (Namibia), Astiptomyia bikos (Namibia). Lectotype designations: Dasypogon andrenoides Wiedemann, 1828; Acnephalum dorsale Macquart, 1838; Acnephalum futile Wulp, 1899. Keys, tables and illustrations are provided for Afrotropical taxa as identification aids while distribution maps are included where appropriate.