The genus Gynothemis was introduced by Calvert (1909), when describing an aberrant member of the Macrothemini from Brazil. The following characteristics were used for this genus: anal area in hind wing with irregularly arranged cells; one row of cells in Rspl, M2 not undulate; triangle in fore wing free, two rows of cells in discoidal field from triangle to wing margin. Femora in both sexes armed with the usual two rows of spines, those of the male not differentiated. Type species: Gynothemis venipunctata Calvert, from Chapada in Brazil. Ris (1913) added two more species to the genus, viz., heteronycha Calvert, described by the author in Brechmorhoga, and calliste Ris, known from one female only. According to Ris, the three species resemble the smaller species of Macrothemis in general appearance, and also in having a similar wing venation. However, they differ from Macrothemis in the structure of the claws, described as very long and thin, with the tooth at about mid-length of the claw, but shorter than the tip. The modification of the spines on the hind femur of males is variable within the genus. In heteronycha this armature consists of a row of 16-18 short triangular spines, directed proximad. In G. venipunctata there are 5 such spines, in G. calliste 10. In uniseta, here described as a new species from Surinam, there is no row of spines at all, but one long seta. It is surprising that three species of Gynothemis have brown basal spots in the wings. The species from Surinam has hyaline wings, except for one female, which shows an orange brown spot in the tip of the wings. There is also some variation in the wing venation: two cubital crossveins in heteronycha, one in the other species; two additional cells in heel of anal