Halictus illinoensis Robertson, 1892:271, ♀. 2 ♀♀, Illinois, Aug. 12. - Dalla Torre, 1896Dalla Torre, C.G. 1896. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, X. Apidae (Anthophila). Sumptibus Guilelmi Engelmann, 1-643. (distribution). - As Dialictus illinoensis: - Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538. (distribution), 399 (comb. nov.); 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). - As Halictus illinoisensis: - 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.:1966 (emendation). - As Halictus illinoisensis: - 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.:1966 (emendation). - As Lasioglossum illinoense: - Owens et al., 2018Owens, B.E., L. Allain, E.C. van Gorder, J.L. Bossart & C.E. Carlton 2018. The bees (Hymenoptera: Apoidea) of Louisiana: An updated, annotated checklist. Proceedings of the Entomological Society of Washington 120 (2):272-307. (distribution).
Halictus politissimus Cockerell, 1917:189, ♀. ♀, San Benito, Texas (leg. W.P. Cockerell). Synonymized with Dialictus illinoensis (Robertson, 1892) by Mitchell, 1960Mitchell, T.B. 1960. Bees of the Eastern United States. Volume I. Technical bulletin (North Carolina Agricultural Experiment Station) 141:1-538.:399. - 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.:1966 ( listed as synonym of Dialictus illinoensis (Robertson, 1892)).