Megachile newberryae Cockerell, 1900:244, ♂. Holotype ♂, Mesilla Park, New Mexico, May 20th, 1900 (leg. Nora Newberry). - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (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.:180 ( listed as synonym of Megachile fidelis Cresson, 1878); 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); 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); 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).
Megachile howardi Cockerell, 1919:216, ♂♀. Holotype ♂, San José de Guaymas, Mexico, April 10 (U.S.N.M., No. 21686, leg. L. O. Howard); 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.:189, Type ♂ (U.S.N.M., no. 21686). - 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); 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.:2071 ( listed as synonym of Megachile newberryae Cockerell, 1900).