The African genus Acanthiops Waltz and McCafferty (Ephemeroptera : Baetidae) is reviewed, redescribed, and figured. The genus is a monophyletic group, easily identified in the larval stage by its distinctive labium, dorsal abdominal armature, claw armature, and two-tailed condition. A previous synonymy of Afroptilum (subgenus Afroptiloides) Gillies with Acanthiops is corroborated. Nominal species included in Acanthiops are A. marlieri (Demoulin) from Zaire, A. tsitsa n. sp. from South Africa, A. variegatus (Gillies) n. comb, from Tanzania, and A. varius (Crass) from South Africa. There are other undescribed species more widespread in sub-Saharan Africa. Species vary considerably and express relative apotypy in development of dorsal armature. Acanthiops tsitsa is described from larvae taken in the North East Cape; it is related to A. varius, but differs in dorsal armature and mouthpart characterization.
