The female sex of Cacus mungo, Gomphoides undulatus, Planiplax phoenicura, Planiplax arachne and Dythemis williamsoni

Single female specimens of dragon flies are often difficult to identify owing to the fact that, when they are known at all, the descriptions are incomplete and mostly lack the essential figure of the genitalia. The following are descriptions of the unknown females of five species, the males of which have been known for the last eighteen to fifty years. They are all complete with figures of the genitalia. The material from which the descriptions have been made has been accumulated during many years of collecting. I am indebted to Mr. J. BELLE, Paramaribo, who was kind enough to place at my disposal, for description, some of the unknown females collected by himself.