Apathus intrudens Smith, 1862:154, ♀. ♀, 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.:175, Type, Col. C. T. Bingham failed to locate this specimen in the collection of the 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); Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19.:13 ( listed as synonym of Bombus variabilis (Cresson, 1872)). - As Bombus intrudens: - Vergara & Ayala, 2002Vergara, C.H. & R. Ayala 2002. Diversity, Phenology and Biogeography of the bees (Hymenoptera: Apoidea) of Zapotitlán de las Salinas, Puebla, Mexico. Journal of the Kansas Entomological Society 75 (1):16-30. (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); Dardón et al., 2020Dardón, M.J., C.L. Yurrita, P. Landaverde-González P. & A.R. Vásquez M. 2020. Rediscovering the diversity of Guatemalan bumble bees (Hymenoptera: Apoidea: Bombus Latreille, 1802). International Journal of Scientific Research in Biological Sciences 7 (2):1-14. (distribution). - As Psithyrus intrudens: - Handlirsch, 1888Handlirsch, A. 1888. Die Hummelsammlung des k. k. naturhistorischen Hofmuseums. Annalen des Naturhistorischen Museums in Wien 3:209-250. (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, 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); 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).
Apathus variabilis Cresson, 1872:284, ♂♀. 5 ♂♀, Texas (leg. Belfrage); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Transactions of the American Entomological Society 38 (3/4):177-486.:461, Types (American Entomological Society). - 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). - As Bombus variabilis: - Abrahamovich & Díaz, 2002Abrahamovich, A.H. & N.B. Díaz 2002. Bumble bees of the Neotropical Region (Hymenoptera: Apidae). Biota Colombiana 3 (2):199-214. (distribution); Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19. (distribution); Dardón et al., 2020Dardón, M.J., C.L. Yurrita, P. Landaverde-González P. & A.R. Vásquez M. 2020. Rediscovering the diversity of Guatemalan bumble bees (Hymenoptera: Apoidea: Bombus Latreille, 1802). International Journal of Scientific Research in Biological Sciences 7 (2):1-14. (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). - As Psithyrus variabilis: - 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. Notes on american bees (Concluded from p. 129). The Entomologist 32:154-159. (distribution); Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (distribution); Franklin, 1913Franklin, H.J. 1913. The Bombidae of the New World. Transactions of the American Entomological Society 38 (3/4):177-486. (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); 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); 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); Mayer et al., 2000Mayer, D.F., E.R. Miliczky, B.F. Finnigan & C.A. Johansen 2000. The bee fauna (Hymenoptera: Apoidea) of southeastern Washington. Journal of the Entomological Society of British Columbia 97:25-32. (distribution); Pascarella, 2006Pascarella, J.B. 2006. The bees of Florida. . (distribution).
Psithyrus guatemalensis Cockerell, 1912:21, ♂. Cockerell, 1912Cockerell, T.D.A. 1912. Descriptions and records of bees. - XLV. The Annals and Magazine of Natural History ser. 8: v. 10 (55):21-31.:22, ♂, Guatemala City, Guatemala (leg. W.P. Cockerell). - 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); Cockerell, 1946Cockerell, T.D.A. 1946. New species and subspecies collected in a month in Guatemala. Journal of the New York Entomological Society 54 (3):203-206. (distribution); Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19.:13 ( listed as synonym of Bombus variabilis (Cresson, 1872)).
Psithyrus bicolor Franklin, 1913:460, xw. Holotype xw, Rociada, New Mexico (Prof. T.D.A. Cockerell's private collection, leg. Prof. Cockerell). - 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); 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.:2207 ( listed as synonym of Psithyrus variabilis (Cresson, 1872)); Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19.:14 ( listed as synonym of Bombus variabilis (Cresson, 1872)).
Psithyrus sololensis Franklin, 1913:173, Type ♂ (Massachusetts Agricultural College). - 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); Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19.:14 ( listed as synonym of Bombus variabilis (Cresson, 1872)). - As Bombus sololensis: - Dardón et al., 2020Dardón, M.J., C.L. Yurrita, P. Landaverde-González P. & A.R. Vásquez M. 2020. Rediscovering the diversity of Guatemalan bumble bees (Hymenoptera: Apoidea: Bombus Latreille, 1802). International Journal of Scientific Research in Biological Sciences 7 (2):1-14. (distribution).
Psithyrus mysticus Frison, 1925:138 - Dardón et al., 2016Dardón, M.J., C.L. Yurrita & M. Vásquez 2016. Catalogue of the bees of the genus Bombus Latreille, 1802 (Hymenoptera: Apoidea: Apidae) in Guatemala. Revista Cientifica 26 (1):9-19.:14 ( listed as synonym of Bombus variabilis (Cresson, 1872)).