In this paper most of the 12 known species and varieties of Dundubia are described and figured. Keys to both sexes of the species are given. Three new species, D. simalurensis, D. solokensis, and D. cochlearata are added. Characters of diagnostic value are chiefly found in the structure of the uncus in the male genitalia and in the shape of the male operculum. In most cases the female sex could be separated on account of the shape of the operculum and the outline of the abdomen. Furthermore, the value of the structure of the male genitalia for establishing the relationship of some genera of the tribe Dundubiini is discussed. The characteristic rounded pygofer indicates the close relationship of the genera Dundubia and Orientopsaltria Kato. In contrast to the condition in these genera we found spine-like projections on both sides of the pygofer in the genera Cosmopsaltria Stål, Diceropyga Stål, Fatima Distant, and Sawda Distant.