In the course of my researches in Surinam a species of Rhodopygia was often collected, the specimens of which answered fairly closely to Dr. F. RIS’s description of Rhodopygia hollandi in the Libellulinae of the DE SELYS collection. However, after studying PH. P. CALVERT’s original description of the species in the Biologia Centrali-Americana (1911, Odonata, p. 318—319, tab. 9, fig. 54) I found my species to be manifestly different in kind from Rhodopygia hollandi, and hence the determination with the aid of RIS’s Libellulinae was incorrect.