Prosopis pygmæa Cresson, 1869:272, ♂. ♂, Illinois (Am. Ent. Soc.). - Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution); Cockerell, 1906Cockerell, T.D.A. 1906. The bees of Florissant, Colorado. Bull. American Mus. Nat. Hist. 22:419-455. (distribution); Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:105 ( listed as synonym of Prosopis cressoni Cockerell, 1907); 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.:1767 ( listed as synonym of Hylaeus mesillae cressoni (Cockerell, 1907)).
Prosopis labiatifrons Cockerell, 1896:437 - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:105 ( listed as synonym of Prosopis cressoni Cockerell, 1907).
Prosopis cressoni Cockerell, 1907:131 - As Hylaeus cressoni: - Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538. (distribution). - As Hylaeus mesillae cressoni: - 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).
Prosopis pasadenae Cockerell, 1910:30 - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:105 ( listed as synonym of Prosopis cressoni Cockerell, 1907); 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.:1767 ( listed as synonym of Hylaeus mesillae cressoni (Cockerell, 1907)).
Prosopis telepora Lovell, 1911:213 - 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.:1767 ( listed as synonym of Hylaeus mesillae cressoni (Cockerell, 1907)).
Hylaeus laciniatus Cockerell & Sumner, 1931:9, ♂. ♂, Colorado, Boulder, May 24, 1913 (leg. F.E. Lutz). - 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.:1767 ( listed as synonym of Hylaeus mesillae cressoni (Cockerell, 1907)).
Hylaeus repolitus Cockerell & Sumner, 1931:13, ♀. ♀, Utah, Ogden, alt. about 4300 ft., July 25, 1920 (leg. F.E. Lutz). - 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.:1767 ( listed as synonym of Hylaeus mesillae cressoni (Cockerell, 1907)).