Epeolus robustus Cresson, 1878:85, ♀. Holotype ♀, New Mexico (leg. Yarrow); Rightmyer, 2008Rightmyer, M.G. 2008. A review of the cleptoparasitic bee genus Triepeolus (Hymenoptera: Apidae).-Part I. Zootaxa 1710:1-170.:111, Lectotype ♀ (Academy of Natural Sciences, No. 2218). - Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution). - As Triepeolus robustus: - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (distribution); Ayala, 1988Ayala, R. 1988. Abejas silvestres (Hymenoptera: Apoidea) de Chamela, Jalisco, México. Folia Entomológica Mexicana 77:395-493. (distribution); Rightmyer, 2008Rightmyer, M.G. 2008. A review of the cleptoparasitic bee genus Triepeolus (Hymenoptera: Apidae).-Part I. Zootaxa 1710:1-170. (distribution).
Epeolus nigriceps Smith, 1879:103, ♀. ♀, California and Texas (British Museum); Cockerell, 1905Cockerell, T.D.A. 1905. Notes on some bees in the British Museum. Transactions of the American Entomological Society 31:309-364.:313, Type ♀ (British Museum); Rightmyer, 2008Rightmyer, M.G. 2008. A review of the cleptoparasitic bee genus Triepeolus (Hymenoptera: Apidae).-Part I. Zootaxa 1710:1-170.:111, Holotype ♀ (The Natural History Museum, London, No. 17B.520). Synonymized with Triepeolus robustus (Cresson, 1878) by Rightmyer, 2008Rightmyer, M.G. 2008. A review of the cleptoparasitic bee genus Triepeolus (Hymenoptera: Apidae).-Part I. Zootaxa 1710:1-170.:111. - Smith, 1879Smith, F. 1879. Descriptions of new species of Hymenoptera in the collection of the British Museum. Taylor and Francis, 1-240. (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, 1903Cockerell, T.D.A. 1903. A catalogue of the bees of California. Psyche 10:74-78. (distribution); Brues, 1903Brues, C.T. 1903. Studies of Texan bees. Part 1. Entomological News 14:79-85. (distribution). - As Triepeolus nigriceps: - 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).