Megachile frugalis Cresson, 1872:266, ♂. Holotype ♂, Texas (G.W. Belfrage); Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VII. Taxonomy of the subgenus Sayapis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (2):175-206.:185, Type ♂ (U.S.N.M., no. 1780); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:77, Type ♂, examined (USNM, 1780); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:93, Type ♂, examined (USNM, 1780). - Cresson, 1879Cresson, E.T. 1879. Catalogue of North American Apidae. Transactions of the American Entomological Society and Proceedings of the Entomological Section of the Academy of Natural Sciences 7:215-232. (distribution); Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution); Cockerell, 1902Cockerell, T.D.A. 1902. Hymenoptera of southern California, II. Bulletin of the Southern California Academy of Science 1 (10):137-140. (distribution); Cockerell, 1903Cockerell, T.D.A. 1903. A catalogue of the bees of California. Psyche 10:74-78. (distribution); Cockerell, 1913Cockerell, T.D.A. 1913. Descriptions and records of bees. - LII. The Annals and Magazine of Natural History ser. 8: v. 11 (66):530-542. (distribution); Cockerell, 1924Cockerell, T.D.A. 1924. Expedition of the California Academy of Sciences to the Gulf of California in 1921. The bees (II). Proceedings of the California Academy of Sciences 12 (27):529-560. (distribution); Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VII. Taxonomy of the subgenus Sayapis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (2):175-206. (distribution); Mitchell, 1962Mitchell, T.B. 1962. Bees of the Eastern United States. Volume II. Technical bulletin (North Carolina Agricultural Experiment Station) 152:1-557. (distribution); Ayala, 1988Ayala, R. 1988. Abejas silvestres (Hymenoptera: Apoidea) de Chamela, Jalisco, México. Folia Entomológica Mexicana 77:395-493. (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); Owens et al., 2018Owens, B.E., L. Allain, E.C. van Gorder, J.L. Bossart & C.E. Carlton 2018. The bees (Hymenoptera: Apoidea) of Louisiana: An updated, annotated checklist. Proceedings of the Entomological Society of Washington 120 (2):272-307. (distribution); Sagot et al., 2018Sagot, P, J. Mérida, R. Ayala & R. Vandame 2018. Situación actual del conocimiento de la fauna de abejas (Apoidea: Anthophila) del estado de Chiapas, México. In: (Ed.). Memorias X Congreso Mesoamericano sobre Abejas Nativas. 191-2011. (distribution); Brindis, 2019Brindis, A.F. 2019. . Dissertation , , 1-143. La Paz, Baja California Sur. (distribution); Esperanza de Pedro, 2021Esperanza de Pedro, D. 2021. . :. (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).