AbstractThe Platisus Erichson fauna of Australia and New Zealand is revised. Six species are recorded, described and illustrated. A key to species is provided. One new species, Platisus vespertinus sp. nov., is described from New South Wales, South Australia, Victoria and Western Australia. This is the first Platisus species known from Western Australia. Platisus bicolor (Olliff, 1885) is removed from synonomy with Platisus coloniarius (Olliff, 1885), which is reinstated in the genus Cucujus. Platisus integricollis Reitter, 1879 is synonymised with P. angusticollis Reitter, 1879. Cucujus coloniarius is provisionally synonymised with the Himalayan species Cucujus bicolor Smith, 1851. Lectotypes are designated for Platisus angusticollis Reitter, 1879, Platisus integricollis Reitter, 1879, Platisus obscurus Erichson, 1842, Ipsaphes bicolor Olliff, 1885, Ipsaphes moerosus Pascoe, 1863, and Cucujus coloniarius Olliff, 1885.