The genera Eremohaplomydas Bequaert, 1959, Haplomydas Bezzi, 1924, and Lachnocorynus Hesse, 1969 (Diptera: Mydidae: Syllegomydinae) are revised. Currently, four species are known from southern Africa, i.e., Eremohaplomydas desertorum Bequaert, 1959 from north-estern Namibia, Haplomydas crassipes Bezzi, 1924 widespread in southern Africa, Lachnocorynus chobeensis Hesse, 1969 from northern Botswana, and Lachnocorynus kochi Hesse, 1969 from northern Namibia. Four new species, Eremohaplomydas gobabebensis sp. nov. and Eremohaplomydas whartoni sp. nov. from the central Namib desert of Namibia, Eremohaplomydas stomachoris sp. nov. from the northern Namib desert in Namibia, and Lachnocorynus stenocephalus sp. nov. from north-eastern Zimbabwe are described. Lachnocorynus kochi is synonymized with Lachnocorynus chobeensis. Distribution, biology, occurrence in biodiversity hotspots sensu Conservation International and seasonal imago flight activity are discussed. Descriptions/redescriptions, photographs, specimen occurrence data, and identification keys (both dichotomous and matrix-based) to species are provided and made openly accessible in data repositories to support and accelerate future studies of the included taxa. An updated identification key to the Mydidae genera of the Afrotropical Region is provided. The placement of the three genera in the subfamily taxon Syllegomydinae is discussed and several morphological features, such as an extremely reduced proboscis in some species, a unique wing venation in Eremohaplomydas gobabebensis sp. nov., and the unique metathoracic coxa, are discussed. Keywords: Afrotropical, cybertaxonomy, Karoo, Mydas flies, Namib Desert, open-access.