Synergus medullæ Ashmead, 1885:302, ♂♀. ♂♂♀♀; Lobato-Vila et al., 2019Lobato-Vila, I., D. Cibrián-Tovar, U.M. Barrera-Rutz, A.Equihua-Martínez, E.G. Estrada-Vebegas, M.L. Buffington & J. Pujade-Villar 2019. Review of the Synergus Hartig species (Hymenoptera: Cynipidae: Synergini) associated with tuberous and other tumor-like galls on oaks from the New World with the description of three new species from Mexico. Proceedings of the Entomological Society of Washington 121 (2):193-255.:224, Lectotype ♀ (USNM, No. 2836); Lobato-Vila & Pujade-Villar, 2021Lobato-Vila, I. & J. Pujade-Villar 2021. The genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) in the New World: a complete taxonomic revision with a key to species. Zootaxa 4906 (1):1-121.:66, Type material (USNM). - Dalla Torre, 1893Dalla Torre, C.G. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, Volumen II: Cynipidae. Breitkopf & Härtel, Leipzig. VIII + 140. (distribution); Gillette, 1896Gillette, C.P. 1896. A monograph of the genus Synergus. Transactions of the American Entomological Society 23:85-100. (listed); 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 1. Symphyta and Apocrita (Parasitica). Smithsonian Institution Press, Washington D.C. 1-1198. (distribution); Pénzes et al., 2012Pénzes, Z. C.-T. Tang, P. Bihari, M. Bozsó, S. Schwéger & G. Melika 2012. Oak associated inquilines (Hymenoptera, Cynipidae, Synergini). TISCIA monograph series 11:1-76. (distribution); Nastasi & Deans, 2021Nastasi, L.F. & A.R. Deans 2021. Catalogue of Rose Gall, Herb Gall, and Inquiline Gall Wasps (Hymenoptera: Cynipidae) of the United States, Canada and Mexico. Biodiversity Data Journal 9 (e68558):1-41. (distribution); Lobato-Vila & Pujade-Villar, 2021Lobato-Vila, I. & J. Pujade-Villar 2021. The genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) in the New World: a complete taxonomic revision with a key to species. Zootaxa 4906 (1):1-121. (distribution).