The cassidine genus Acromis Chevrolat is revised. A key for identification of adults, illustrated descriptions and extensive distribution data for the three species are provided. Eggs and mature larvae of A. spinifex (Linnaeus) are redescribed. A cladistic analysis of species based on 19 morphological characters is done using the stolaine genera Omaspides Chevrolat and Echoma Chevrolat, as well as Delocrania cossyphoides Guerin (Delocraniini) and Himatidium capense Herbst (Imatidiini) as outgroups. The resulting single most parsimonious tree (steps = 20; CI = 87; RI = 90) provides strong support for resolution within Acromis. Biological implications are discussed in light of the cladogram.