A taxonomic analysis is presented of the closely related general Culmacris and Stiletta, in the morabine grasshopper tribe Warramungini. Culmacris is treated as comprising four species, orientalis, curvicercus, archaica, and diversa (the last two new) and 13 races within diversa. These taxa occupy a mosaic of 16 non-sympatric, almost certainly parapatric, ranges covering between them a large part of the northern half of Australia. The 13 races of diversa are diagnosed primarily on karyotypic characters following White's findings in a companion paper; they are grouped into 'race groups' and one ungrouped race, on characters of the male genitalia. Stiletta, with two probably parapatric species nitida and mesai, the latter new and the former with two component races, occupies a small area straddling the border of Western Australia and the Northern Territory in the region of the Ord and Victoria Rivers. It is sympatric with Culmacris in the Victoria River area. Keys to the genera of Warramungini and the species of Culmacris and Stiletta are provided.