Megachile albitarsis Cresson, 1872:263, ♂. 2 ♂♂, Texas (leg. Belfrage); Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (1):45-83.:77, Type ♂ (A.N.S.P., no. 2461); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:15, Type ♂, examined (ANSP, 2461); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11, Type ♂, examined (ANSP, 2461). - Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution); Cockerell, 1911Cockerell, T.D.A. 1911. Bees in the collection of the United States National Museum. 2. Proceedings of the United States National Museum 40 (1818):241-264. (distribution); 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); Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (1):45-83. (distribution); Michener, 1947Michener, C.D. 1947. Bees of a limited area in southern Mississippi (Hymenoptera; Apoidea). The American Midland Naturalist 38 (2):443-455. (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); Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington D.C. 1199-2209. (distribution); Ayala, 1988Ayala, R. 1988. Abejas silvestres (Hymenoptera: Apoidea) de Chamela, Jalisco, México. Folia Entomológica Mexicana 77:395-493. (distribution); Estrada de Léon & Ayala Barajas, 1995Estrada de Léon, M. & R. Ayala Barajas 1995. Abejas silvestres (Hymenoptera: Apoidea) de la Sierra del Tigre, Jalisco. Apicultura Moderna 7:12-24. (distribution); Pascarella et al., 1999Pascarella, J.B., Waddington, K.D. & Neal, P.R. 1999. The Bee Fauna (Hymenoptera: Apoidea) of Everglades National Park, Florida and adjacent areas: Distribution, Phenology, and Biogeography. Journal of the Kansas Entomological Society 72 (1):32-45. (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); Yáñez-Ordóñez & Hinojosa-Díaz, 2004Yáñez-Ordóñez, O. & I. Hinojosa-Díaz 2004. La colección himenopterológica (Insecta) del Museo de Zoología Alfonso L. Herrera de la Facultad de Ciencias, UNAM, México. Acta Zoológica Mexicana (nueva serie) 20 (1):167-197. (distribution); Pascarella, 2006Pascarella, J.B. 2006. The bees of Florida. . (distribution); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127. (distribution); Hall & Ascher, 2010Hall, H.G., & J.S. Ascher 2010. Surveys of bees (Hymenoptera: Apoidea: Anthophila) in natural areas of Alachua County in North-Central Florida. The Florida Entomologist 93 (4):609-629. (distribution); Hall & Ascher, 2011Hall, H.G., & J.S. Ascher 2011. Surveys of wild bees (Hymenoptera: Apoidea: Anthophila) in organic farms of Alachua County in north-central Florida. The Florida Entomologist 94 (3):539-552. (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); 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).
Megachile optiva Cresson, 1872:268, ♀. 2 ♀♀, Texas (leg. Belfrage); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:15, Type ♀, examined (ANSP, 2445); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11, Type ♀, examined (ANSP, 2445). - 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); Robertson, 1897Robertson, C. 1897. North American bees - Descriptions and synonyms. Transactions of the Academy of Science of St. Louis 7 (14):315-356. (distribution); Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (1):45-83.:75 ( listed as synonym of Megachile albitarsis Cresson, 1872); Mitchell, 1962Mitchell, T.B. 1962. Bees of the Eastern United States. Volume II. Technical bulletin (North Carolina Agricultural Experiment Station) 152:1-557.:165 ( listed as synonym of Megachile albitarsis Cresson, 1872); Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington D.C. 1199-2209.:2069 ( listed as synonym of Megachile albitarsis Cresson, 1872); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11 ( listed as synonym of Megachile albitarsis Cresson, 1872).
Megachile newelli Cockerell, 1908:262, ♀. 2 ♀♀, Keatchie, Louisiana, July 8, 1905 (leg. Wilmon Newell); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:15, Type ♀. - Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (1):45-83.:75 ( listed as synonym of Megachile albitarsis Cresson, 1872); Mitchell, 1962Mitchell, T.B. 1962. Bees of the Eastern United States. Volume II. Technical bulletin (North Carolina Agricultural Experiment Station) 152:1-557.:165 ( listed as synonym of Megachile albitarsis Cresson, 1872); Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington D.C. 1199-2209.:2069 ( listed as synonym of Megachile albitarsis Cresson, 1872); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11 ( listed as synonym of Megachile albitarsis Cresson, 1872).
Megachile kallstræmiæ Cockerell, 1908:264, ♀. ♀, Mesilla Park, New Mexico, July 15-27 (leg. Cockerell); ♀, Las Cruces, New Mexico, Sept. 9 (leg. C.H.T. Townsend); Raw, 2004Raw, A. 2004. Leafcutter and Mason Bees: a biological catalogue of the genus Megachile of the Neotropics. :1-97.:15, Type ♀. - Mitchell, 1937Mitchell, T.B. 1937. A revision of the genus Megachile in the Nearctic Region. Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63 (1):45-83.:75 ( listed as synonym of Megachile albitarsis Cresson, 1872); Mitchell, 1962Mitchell, T.B. 1962. Bees of the Eastern United States. Volume II. Technical bulletin (North Carolina Agricultural Experiment Station) 152:1-557.:165 ( listed as synonym of Megachile albitarsis Cresson, 1872). - As Megachile kallstroemiae: [lapsus] - Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington D.C. 1199-2209.:2069 ( listed as synonym of Megachile albitarsis Cresson, 1872); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11 ( listed as synonym of Megachile albitarsis Cresson, 1872). - As Megachile kallstroemiae: [lapsus] - Krombein et al., 1979Krombein, K.V., P.D. Hurd, D.R. Smith & B.D. Burks 1979. Catalog of Hymenoptera in America North of Mexico. Volume 2. Apocrita (Aculeata). Smithsonian Institution Press, Washington D.C. 1199-2209.:2069 ( listed as synonym of Megachile albitarsis Cresson, 1872); Raw, 2007Raw, A. 2007. An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa 1601:1-127.:11 ( listed as synonym of Megachile albitarsis Cresson, 1872).