Keys, descriptions, and illustrations distinguish the known species of the Middle American genus Onypterygia Dejean (type species Onypterygia fulgens Dejean), and each taxon is characterized in terms of structural features of adults, habitat, geographical distribution, and chorological affinities. For allopatric species that are markedly similar in structural features, a hypothesis of phylogenetic relationship is postulated. Fifteen new species are described. The species of Onypterygia are arranged in seven groups, sequenced according to judgment about extent of departure from a generalized platynine body plan (type areas for new species in parentheses): O. famini group, including O. famini Solier and O. cyanea Chaudoir; O. wappesi group, including O. wappesi, n. sp. (Mexico, Guerrero, Sierra de Atoyac); O. amecameca, n. sp. (Mexico, state of Mexico, Amecameca):, O. atoyac, n. sp. (Mexico, Guerrero, Sierra de Atoyac); O. shpeleyi, n. sp. (Mexico, Guerrero, Sierra de Atoyac); and O. pacifica, n. sp. (Mexico, Oaxaca, Sierra de Miahuatlan); O. aeneipennis group, including O. batesi, n. sp. (Mexico, Tamaulipas, Sierra Madre Oriental [Sierra de Guatemala]), O. aeneipennis Chaudoir, O. cupricauda Casey, O. stenapteryx, n. sp. (Mexico, Michoacan, Sierra Transvolcanica West), O. pallidipes Chaudoir, and O. rubida Bates; the O. perissostigma group, including only O. perissostigma, n. sp. (Mexico, Oaxaca, Sierra de Juarez), the O. pusilla group, including O. pusilla Chaudoir and O. rawlinsi, n. sp. (Mexico, Nayarit, Sierra Transvolcanica West); the O. angustata group, including O. longispinis Bates, O. angustata Chevrolat, O. pseudangustata, n. sp. (Mexico, Puebla, Sierra Trans-volcanic East), and O. striblingi, n. sp. (Mexico, Oaxaca, Sierra de Juarez); and O. fulgens group, including O. iris Chaudoir, O. championi Bates, O. donate Ball and Shpeley, O. chrysura Bates, O. kathleenae, n. sp. (Mexico, Oaxaca, Sierra de Juarez), O. exeuros, n. sp. (Mexico, Oaxaca, Sierra de Juarez), O. polytreta, n. sp. (Panama, Chiriqui Province, Talamancan Cordillera, Cerro Pando), O. crabilli, n. sp. (Costa Rica, Puntarenas Province, Talamancan Cordillera, Monteverde), O. quadrispinosa Bates, O. scintillans, n. sp. (probably Costa Rica, Talamancan Cordillera), O. Sulgens Dejean, O. tricolor Dejean, O. hoepfneri Dejean, and O. sallei Chaudoir. New synonymy is as follows: O. cyanea Chaudoir, 1878 = O. valdestriata Bates, 1884; O. fulgens Dejean, 1831 = O. thoreyi Mannerheim, 1844; O. tricolor Dejean, 1831 = O. apicalis Chaudoir, 1837 = O. tricolor var. dimidiata Chevrolat, 1837. Other synonyms are as published by previous authors. Geographical distribution of Onypterygia is analyzed in terms of altitudinal range, and nine areas of precinction, each of which is highland isolated by surrounding lowlands. The areas are, from south to north: Talamancan Cordillera; Chiapan-Guatemalan Highlands; Sierra Madre de Oaxaca; Sierra de Miahuatlan; Sierra de Atoyac; Sierra Transvolcanica East and West; Sierra Madre Oriental and Occidental. Seven areas have representatives of four to six species groups, but the northwestern most (Sierra Madre Occidental) and southernmost (Talamancan Cordillera) have only two groups. At the species level, the northern centers (Sierra Madre Oriental and Occidental) lack precinctive species, but the southern Talamancan Cordillera has nine such species. Speciation, then, has been most frequent in the more southerly centers. Probably the northern centers have been invaded relatively recently, or evidence of older invasions has been lost because of extinctions.
