Aegimia Stål, 1874, a Neotropical katydid genus of the Phaneropterinae (Orthoptera: Tettigoniidae), is revised based on the examination of 106 specimens from Mexico, Costa Rica, Panama, Colombia and Brazil. The genus is recognized by a long sword-shaped fastigium, mid- and hindtibiae strongly flattened, and leaf-shaped tegmina. The following species are redescribed: A. catharinensis Piza, 1950, A. cultrifera Stål, 1874 and A. elongata Rehn, 1903. Two new species are described: Aegimia maculifolia sp. nov. (from Costa Rica, Panama and Colombia) and Aegimia venarecta sp. nov. (from Costa Rica). Geographic distribution of A. cultrifera is expanded to Costa Rica. The female of A. catharinensis remains unknown. A pictorial key to all species is presented and details of the male genitalic characters described and illustrated.