Subaeschna Martin, 1908, is synonymized with Gynacantha Rambur, 1842, and its only sp., S. francesca Martin, 1909, becomes Gynacantha francesca (Martin). G. bartai sp. n. is described from 5 specimens (holotype 6 and allotype 9; Peru, Madre de Dios, Explorer’s Inn; deposited in the NMNH, Washington, DC, USA) from southern Peru. It is characterized by very small size, unmarked thorax, straight cerci, and abdomen constricted in 6 and unconstricted in 9.