Perdita fallax Cockerell, 1896:90, ♀. 2 ♀♀, Las Cruces, N. M., Sept. 23, 1895 (leg. Cockerell). - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (distribution); Swenk & Cockerell, 1907Swenk, M.H. & Cockerell, T.D.A. 1907. The bees of Nebraska. - I. Entomological News 18:51-58. (distribution); Timberlake, 1960Timberlake, P.H. 1960. A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea). Part IV. University of California Publications In Entomology 17 (1):1-156. (distribution); Timberlake, 1968Timberlake, P.H. 1968. A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea). Part VII. University of California Publications In Entomology 49:1-196. (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).
Perdita erigeronis Cockerell, 1897:398, ♂. 3 ♂♂, Woodlands Orchard, Mesilla, N. M., May 9, 1896. - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (distribution); Timberlake, 1960Timberlake, P.H. 1960. A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea). Part IV. University of California Publications In Entomology 17 (1):1-156.:106 ( listed as synonym of Perdita fallax Cockerell, 1896); 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.:1898 ( listed as synonym of Perdita fallax Cockerell, 1896).
Perdita fallax fontis Cockerell, 1922:9, ♀. Holotype ♀, Colorado: Glenwood Springs, August 5, 1920; Timberlake, 1968Timberlake, P.H. 1968. A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea). Part VII. University of California Publications In Entomology 49:1-196.:75, Type ♀ (American Museum of Natural History). Synonymized with Perdita fallax Cockerell, 1896 by Timberlake, 1968Timberlake, P.H. 1968. A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea). Part VII. University of California Publications In Entomology 49:1-196.:74. - 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.:1898 ( listed as synonym of Perdita fallax Cockerell, 1896).