Colletes nigrifrons Titus, 1900:304, Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527.:433, Neotype ♀ (Snow Entomological Collections of the University of Kansas). - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of Florissant, Colorado. Bull. American Mus. Nat. Hist. 22:419-455. (distribution); Cockerell, 1907Cockerell, T.D.A. 1907. The bees of Boulder County, Colorado. University of Colorado Studies 4:239-259. (distribution); Cockerell, 1923Cockerell, T.D.A. 1923. Some Colorado bees. The Canadian Entomologist 55:205-206. (distribution); Timberlake, 1943Timberlake, P.H. 1943. Bees of the genus Colletes chiefly from Colorado. Bulletin of the American Museum of Natural History 81 (5):385-410. (distribution); Timberlake, 1951Timberlake, P.H. 1951. Western bees of the genus Colletes (Hymenoptera: Apoidea). The Wasmann Journal of Biology 9 (2):181-238. (distribution); Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527. (distribution); Wilson et al., 2010Wilson, J.S., L.E. Wilson, L.D. Loftis & T. Griswold 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70 (2):198-207. (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).
Colletes florissantia Cockerell, 1906:425, ♂. Type ♂, Florissant, June 22 (leg. R.); Timberlake, 1943Timberlake, P.H. 1943. Bees of the genus Colletes chiefly from Colorado. Bulletin of the American Museum of Natural History 81 (5):385-410.:387, Type ♂ (Riverside); Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527.:433, Holotype (Citrus Experiment Station, Riverside, California). Synonymized with Colletes nigrifrons Titus, 1900 by Timberlake, 1943Timberlake, P.H. 1943. Bees of the genus Colletes chiefly from Colorado. Bulletin of the American Museum of Natural History 81 (5):385-410.:387. - Cockerell, 1907Cockerell, T.D.A. 1907. The bees of Boulder County, Colorado. University of Colorado Studies 4:239-259. (distribution); Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527.:430 ( listed as synonym of Colletes nigrifrons Titus, 1900).
Colletes polemonii Cockerell, 1906:425, ♂. Type ♂, Florissant, June 27 (leg. R.); Timberlake, 1943Timberlake, P.H. 1943. Bees of the genus Colletes chiefly from Colorado. Bulletin of the American Museum of Natural History 81 (5):385-410.:387, Type ♂ (Riverside); Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527.:433, Holotype (Citrus Experiment Station, Riverside, California). Synonymized with Colletes nigrifrons Titus, 1900 by Timberlake, 1943Timberlake, P.H. 1943. Bees of the genus Colletes chiefly from Colorado. Bulletin of the American Museum of Natural History 81 (5):385-410.:387. - Cockerell, 1907Cockerell, T.D.A. 1907. The bees of Boulder County, Colorado. University of Colorado Studies 4:239-259. (distribution); Stephen, 1954Stephen, W.P. 1954. A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae). University of Kansas Science Bulletin 36:149-527.:430 ( listed as synonym of Colletes nigrifrons Titus, 1900).