Bombus modestus Smith, 1862:153, ♀. ♀, Oajaca (Mexico) (British Museum); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Part II - Species south of the United States. Transactions of the American Entomological Society 39 (2):73-200.:83, xq (probably still extant in the collection of the British Museum, but Col. C. T. Bingham failed to establish its identity for me); Meade-Waldo, 1916Meade-Waldo, G. 1916. Notes on the Apidae (Hymenoptera) in the collecition of the British Museum, with description of new species. The Annals and Magazine of Natural History ser. 8: v. 17:448-470.:469, Type (British Museum). - Cresson, 1863Cresson, E.T. 1863. List of North American species of Bombus and Apathus. Proceedings of the Entomological Society of Philadelphia 2:83-116. (distribution); 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); Cockerell, 1899Cockerell, T.D.A. 1899. Catálogo de las Abejas de Mexico. Biblioteca Agricola de las Secretaria de Fomento, Mexico, 1-20.:19 ( listed as synonym of Bombus trinominatus Dalla Torre, 1890); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Part II - Species south of the United States. Transactions of the American Entomological Society 39 (2):73-200.:83 ( listed as synonym of Bombus trinominatus Dalla Torre, 1890); Meade-Waldo, 1916Meade-Waldo, G. 1916. Notes on the Apidae (Hymenoptera) in the collecition of the British Museum, with description of new species. The Annals and Magazine of Natural History ser. 8: v. 17:448-470.:469 ( listed as synonym of Bombus trinominatus Dalla Torre, 1890); Lutz & Cockerell, 1920Lutz, F.E. & T.D.A. Cockerell 1920. Notes on the distribution and bibliography of North American bees of the families, Apidae, Meliponidae, Bombidae, Euglossidae, and Anthophoridae. Bull. Amer. Mus. Nat. Hist 42 (15):491-641.:537 ( listed as synonym of Bombus trinominatus Dalla Torre, 1890).
Bombus trinominatus Dalla Torre, 1890:139 Replacement name for Bombus modestus Smith, 1862 by Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643.:559 (nec Cresson, nec Eversmann). - Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution); Cockerell, 1899Cockerell, T.D.A. 1899. Catálogo de las Abejas de Mexico. Biblioteca Agricola de las Secretaria de Fomento, Mexico, 1-20. (distribution); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Transactions of the American Entomological Society 38 (3/4):177-486. (distribution); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Part II - Species south of the United States. Transactions of the American Entomological Society 39 (2):73-200. (distribution); Lutz & Cockerell, 1920Lutz, F.E. & T.D.A. Cockerell 1920. Notes on the distribution and bibliography of North American bees of the families, Apidae, Meliponidae, Bombidae, Euglossidae, and Anthophoridae. Bull. Amer. Mus. Nat. Hist 42 (15):491-641. (distribution); Abrahamovich & Díaz, 2002Abrahamovich, A.H. & N.B. Díaz 2002. Bumble bees of the Neotropical Region (Hymenoptera: Apidae). Biota Colombiana 3 (2):199-214. (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).