The generaEremohaplomydasBequaert, 1959,HaplomydasBezzi, 1924, andLachnocorynusHesse, 1969 (Diptera: Mydidae: Syllegomydinae) are revised. Currently, four species are known from southern Africa,i.e.,Eremohaplomydas desertorumBequaert, 1959 from north-western Namibia,Haplomydas crassipesBezzi, 1924 widespread in southern Africa,Lachnocorynus chobeensisHesse, 1969 from northern Botswana, andLachnocorynus kochiHesse, 1969 from northern Namibia. Four new species,Eremohaplomydas gobabebensissp. nov.andEremohaplomydas whartonisp. nov.from the central Namib desert of Namibia,Eremohaplomydas stomachorissp. nov.from the northern Namib desert in Namibia, andLachnocorynus stenocephalussp. nov.from north-eastern Zimbabwe are described.Lachnocorynus kochiis synonymized withLachnocorynus chobeensis. Distribution, biology, occurrence in biodiversity hotspotssensuConservation 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 inEremohaplomydas gobabebensissp. nov., and the unique metathoracic coxa, are discussed.