Megachile nigromixta Cockerell, 1919:215, ♂. Holotype ♂, Mexico (U.S.N.M., No. 21684, leg. Baker collection); Raw, 2002Raw, A. 2002. New combinations and synonymies of leafcutter and mason bees of the Americas (Megachile, Hymenoptera, Megachilidae). Zootaxa 71:1-43.:25, Type ♂ (USNM, 21684); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:55, Type ♂, examined (USNM, 21684); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:66, Type ♂ (USNM, 21684). - Cockerell, 1919Cockerell, T.D.A. 1919. Bees in the collection of the United States National Museum. Proceedings of the United States National Museum 55 (2264):167-221. (distribution); Cockerell, 1923Cockerell, T.D.A. 1923. Some bees from Victoria, Mexico. Proceedings of the United States National Museum 63 (Art. 8):1-5. (distribution); Raw, 2002Raw, A. 2002. New combinations and synonymies of leafcutter and mason bees of the Americas (Megachile, Hymenoptera, Megachilidae). Zootaxa 71:1-43. (distribution); Ruíz-Cancino & Coronado-Blanco, 2002Ruíz-Cancino, E. & J.M. Coronado-Blanco 2002. Artrópodos terrestres de los estados de Tamaulipas y Nuevo León, México. Serie Publicaciones Cientificas No. 4:1-376. (distribution); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97. (distribution); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127. (distribution); Nava-Bolaños & Osorio-Olvera, 2022Nava-Bolaños, A. & L. Osorio-Olvera 2022. Estado del arte del conocimiento de biodiversidad de los polinizadores de México. Revista Mexicana de Biodiversidad 93:1-77. (distribution).