Abstract
Of the six species of Australian Rhysida recognized by Chamberlin (1920), three are synonymized and one is excluded from Australia. Three Australian species of Rhysida are recognized: R. carinulata (Haase) and R. nuda (Newport) are redescribed, and a new species, R. polyacantha, is described. These three species are keyed, their distributions in Australia mapped, and some of their important characters tabulated together with those of two related extralimital Rhysida species, immarginata and longipes. R. nuda is confined to Australia. Hence all the extralimital forms of Rhysida to which previous workers have applied the specific or subspecific name nuda should not bear that name. The name R. immarginata may be applicable to some or most of those forms.