Kevan 1956. Flightless African genera of Pyrgomorphine grasshoppers allied, or superficially similar, to Parasphena I. Bolvar, 1884, and Pyrgomorphella I. Bolvar, 1904, with descriptions of certain new forms (Orthoptera: Acrididae). Publicacoes Culturais da Companhia de Diamantes de Angola, no. 29 1956: 109-133