- As Hylaeus modestus modestus: - Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538. (distribution); Hall & Ascher, 2010Hall, H.G., & J.S. Ascher 2010. Surveys of bees (Hymenoptera: Apoidea: Anthophila) in natural areas of Alachua County in North-Central Florida. The Florida Entomologist 93 (4):609-629. (distribution); Hall & Ascher, 2011Hall, H.G., & J.S. Ascher 2011. Surveys of wild bees (Hymenoptera: Apoidea: Anthophila) in organic farms of Alachua County in north-central Florida. The Florida Entomologist 94 (3):539-552. (distribution).
Prosopis affinis Cresson, 1869:270, ♂♀.Ct., N. Y., Pa., Va., Ill., Col. Ter. (Am. Ent. Soc.). - Cresson, 1869Cresson, E.T. 1869. Description of North American bees. No. 2. Proceedings of the Boston Society of Natural History 12:269-274. (distribution); Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:65 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosapis pennsylvanica Cockerell, 1896:439, ♂. ♂, Montgomery Co., Pa., May 28, 1890 (U. S. Natl. Museum); ♂, Virginia, June 27, 1880 (leg. C.V. Riley). - Cockerell, 1898Cockerell, T.D.A. 1898. The North American bees of the genus Prosapis. The Entomologist 31:185-192. (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.:1762 ( listed as synonym of Hylaeus modestus modestus Say, 1837). - As Prosopis pennsylvanica: - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:121 ( listed as synonym of Prosopis modestus (Say, 1837)); Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:65 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosapis citrinifrons Cockerell, 1896:27, ♂. ♂, Colorado; Forrester's Ranch on Laramie River, Larimer Co., 8500 feet, July 19, 1895 (leg. C.F. Baker). - As Hylaeus modestus citrinifrons: - Snelling, 1966Snelling, R.R. 1966. Studies on North American bees of the genus Hylaeus. 1. Distribution of the western species of the subgenus Prosopis with descriptions of new forms (Hymenoptera: Colletidae). Contributions in Science, Natural History Museum Los Angeles County 98:1-18. (distribution). - As Prosopis citrinifrons: - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:121 ( listed as synonym of Prosopis modestus (Say, 1837)).
Hylaeus rugosulus Cockerell, 1896 Synonymized with Hylaeus modestus citrinifrons (Cockerell, 1896) by Snelling, 1975Snelling, R.R. 1975. Taxonomic notes on some colletid bees of western North America with descriptions of new species (Hymenoptera: Colletidae). Contributions in Science, Natural History Museum Los Angeles County 267:1-8.:7. - Snelling, 1975Snelling, R.R. 1975. Taxonomic notes on some colletid bees of western North America with descriptions of new species (Hymenoptera: Colletidae). Contributions in Science, Natural History Museum Los Angeles County 267:1-8. (distribution).
Hylaeus rugosulus fallax Cockerell, 1896 Synonymized with Hylaeus modestus citrinifrons (Cockerell, 1896) by Snelling, 1975Snelling, R.R. 1975. Taxonomic notes on some colletid bees of western North America with descriptions of new species (Hymenoptera: Colletidae). Contributions in Science, Natural History Museum Los Angeles County 267:1-8.:7. - Snelling, 1975Snelling, R.R. 1975. Taxonomic notes on some colletid bees of western North America with descriptions of new species (Hymenoptera: Colletidae). Contributions in Science, Natural History Museum Los Angeles County 267:1-8. (distribution).
Prosopis nucleolus Viereck, 1903:64 - Cockerell, 1906Cockerell, T.D.A. 1906. The bees of New Mexico. Transactions of the American Entomological Society 32:289-314. (distribution); Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:65 ( listed as synonym of Hylaeus modestus modestus Say, 1837); 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.:1763 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosopis sayi Robertson, 1904:274 - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:122 ( listed as synonym of Prosopis modestus (Say, 1837)); Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:65 ( listed as synonym of Hylaeus modestus modestus Say, 1837); 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.:1763 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosopis minyra Lovell, 1909:413, ♂. Holotype ♂, Church Bridge, Va., June 9 (leg. N. Banks). - Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:66 ( listed as synonym of Hylaeus modestus modestus Say, 1837); 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.:1763 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosopis binghami Lovell, 1910:180 Synonymized with Hylaeus modestus modestus Say, 1837 by Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:66. - 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.:1763 ( listed as synonym of Hylaeus modestus modestus Say, 1837).
Prosopis supracurta Swenk & Cockerell, 1910:71, ♂. Holotype ♂, Ute Creek, Colorado, July 17, 1907 (University of Nebraska, leg. R.W. Dawson); Muma, 1952Muma, M.H. 1952. Insect types in the collections of the University of Nebraska State Museum. Bulletin of the University of Nebraska State Museum 3 (8):1-35.:22, Type ♂ (University of Nebraska State Museum). - Metz, 1911Metz, C.W. 1911. A revision of the genus Prosopis in North America. Transactions of the American Entomological Society 37:85-156.:122 ( listed as synonym of Prosopis modestus (Say, 1837)); Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:66 ( listed as synonym of Hylaeus modestus modestus Say, 1837); 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.:1763 ( listed as synonym of Hylaeus modestus modestus Say, 1837).