ABSTRACT: The Afrotropical representatives of the hover fly genus Mesembrius Rondani, 1857 (Diptera) are divided into two subgenera, namely Mesembrius s.s. and Vadonimyia Séguy, 1951 and, in this present work, the subgenus Mesembrius s.s. is revised. A total of 23 Mesembrius s.s. species are recognised for the Afrotropics. Known species are re-described and six species new to science are described: Mesembrius arcuatus sp. nov., M. copelandi sp. nov., M. longipilosus sp. nov., M. sulcus sp. nov., M. tibialis sp. nov. and M. vockerothi sp. nov. Mesembrius africanus (Verrall, 1898) is considered a junior synonym of M. senegalensis (Macquart, 1842), M. ctenifer Hull, 1941 a junior synonym of M. caffer (Loew, 1858), M. lagopus (Loew, 1869) a junior synonym of M. capensis (Macquart, 1842) and M. platytarsis Curran, 1929 a junior synonym of M. simplicipes Curran, 1929. The females of Mesembrius chapini Curran, 1939, M. rex Curran, 1927 and M. regulus (Hull, 1937) are described for the first time. Lectotypes are designated for Mesembrius caffer, M. capensis, M. cyanipennis (Bezzi, 1915), M. minor (Bezzi, 1915), M. senegalensis, M. strigilatus (Bezzi, 1912) and M. tarsatus (Bigot, 1883). Separate identification keys for males and females are presented. We obtained 236 DNA barcodes for 18 species. The relationships amongst the different Mesembrius species are briefly discussed, based on morphological and DNA barcode data.
