A new species, Endaphis gracilistylus Gagné & Etienne, is described and illustrated. It is an internal parasitoid of an undescribed species of Mitrapsylla (Psyllidae) found feeding on Machaerium lunatum (L.f.) Ducke in Guadeloupe, F.W.I. The genus Endaphis Kieffer is redescribed and each of the ten previously described species is reviewed for recognition characters. A key is presented to nine species; two species remain too poorly known for recognition. Endopsylla Meijere is considered a junior synonym of Endaphis.