Three new species of Rhizomyces Thaxt., parasitic on African stalk-eyed flies, are described. These are R. forcipatus W.Rossi & Feijen sp. nov., parasitic on various species of Centrioncus Speiser from Ivory Coast, Kenya and Malawi and Teloglabrus Feijen from South Africa; R. ramosus W.Rossi & Feijen sp. nov., parasitic on Diopsina nitida (Adams, 1903) from Uganda; R. tschirnhausii W.Rossi & Feijen sp. nov., parasitic on Diopsina africana (Shillito, 1940) from Uganda. All previous records of species of Rhizomyces are presented in tabulated form with updated host names. A key is presented to all species of Rhizomyces. The occurrence of Rhizomyces and other taxa of the Laboulbeniales Lindau in the genera of the Diopsidae Billberg is discussed.