Mesostenus gracilis Cresson, 1864:315, ♂. ♂, Virginia (leg. Dr. Thomas B. Wilson); Townes & Townes, 1962Townes, H.K. & M. Townes 1962. Ichneumon-flies of America north of Mexico: 3. Subfamily Gelinae, tribe Mesostenini. Bulletin of the United States National Museum 216 (3):1-602.:443, Type ♂ (Philadelphia); Kasparyan & Ruíz-Cancino, 2008Kasparyan, D.R. & E. Ruíz Cancino 2008. Cryptini de México (Hymenoptera: Ichneumonidae: Cryptinae) Parte II. Victoría, México. 1-373.:254, Type ♂ (Mus. Philadelphia). - Cresson, 1872Cresson, E.T. 1872. Hymenoptera Texana. Transactions of the American Entomological Society 4:153-292. (distribution); Dalla Torre, 1901-1902Dalla Torre, C.G. 1901-1902. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. — Volumen III: Trigonalidae, Megalyridae, Stephanidae, Ichneumonidae, Agriotypidae, Evaniidae, Pelecinidae. Pars II. Breitkopf & Härtel, Leipzig. VIII + 1141. (distribution); Cushman, 1929Cushman, R.A. 1929. A revision of the North American Ichneumon-flies of the genus Mesostenus and related genera. Proceedings of the United States National Museum 74 (art. 16):1-58. (distribution); Townes & Townes, 1962Townes, H.K. & M. Townes 1962. Ichneumon-flies of America north of Mexico: 3. Subfamily Gelinae, tribe Mesostenini. Bulletin of the United States National Museum 216 (3):1-602. (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 1. Symphyta and Apocrita (Parasitica). Smithsonian Institution Press, Washington D.C. 1-1198. (distribution); Ruíz-Cancino et al., 2002Ruíz-Cancino, E., D.R. Kasparyan & J.M. Coronado Blanco 2002. Ichneumonidae. In: Llorente Bousquets, J. & J.J. Morrone (Ed.). Biodiversidad, taxonomía y biogeografía de artrópodos de México: Hacia una síntesis de su conocimiento, volumen III. 631-646. (distribution); Ruíz-Cancino & Coronado-Blanco, 2002Ruíz-Cancino, E. & J.M. Coronado-Blanco 2002. Artrópodos terrestres de los estados de Tamaulipas y Nuevo León, México. Serie Publicaciones Cientificas No. 4:1-376. (distribution); Kasparyan & Ruíz-Cancino, 2008Kasparyan, D.R. & E. Ruíz Cancino 2008. Cryptini de México (Hymenoptera: Ichneumonidae: Cryptinae) Parte II. Victoría, México. 1-373. (distribution); Ruíz-Cancino, 2010Ruíz-Cancino E. 2010. Ichneumonidae (Hymenoptera) de Tamaulipas, México. Editorial Planea, México. 185 pp. (distribution); Ruíz-Cancino et al., 2010Ruíz-Cancino, E., D.R. Kasparyan, J.M. Coronado-Blanco, S.N. Myartseva, V.A. Trjapitzin, S.G. Hernández Aguilar & J. García Jiménez 2010. Himenópteros de la Reserva “El Cielo”, Tamaulipas, México. Dugesiana 17 (1):53-71. (distribution); Ruíz-Cancino et al., 2013Ruíz-Cancino, E., J.M. Coronado-Blanco, J. Cambero-Campos & A.I. Khalaim 2013. Conocimiento actual de los Ichneumonidae (Hymenoptera) de los estados de Nayarit y Sinaloa, México. Entomología mexicana 12 (2):1420-1425. (distribution); Rodríguez-Mota et al., 2015Rodríguez-Mota, A.J., E. Ruíz-Cancino, A.I. Khalaim, J.M. Coronado-Blanco & J. Treviño-Carreónj 2015. Diversidad de Ichneumonidae (Hymenoptera) en un bosque de Pinus spp. y Juniperus flaccida en Jaumave, Tamaulipas, México. Revista Mexicana de Biodiversidad 86:972-980. (distribution).
Nematopodius orbitalis Ashmead, 1890:21, ♀. Holotype ♀, West Cliff (leg. Cockerell); Townes & Townes, 1962Townes, H.K. & M. Townes 1962. Ichneumon-flies of America north of Mexico: 3. Subfamily Gelinae, tribe Mesostenini. Bulletin of the United States National Museum 216 (3):1-602.:443, Type ♀ (Washington). Synonymized with Mesostenus gracilis Cresson, 1864 by Cushman, 1929Cushman, R.A. 1929. A revision of the North American Ichneumon-flies of the genus Mesostenus and related genera. Proceedings of the United States National Museum 74 (art. 16):1-58.:43. - Dalla Torre, 1901-1902Dalla Torre, C.G. 1901-1902. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. — Volumen III: Trigonalidae, Megalyridae, Stephanidae, Ichneumonidae, Agriotypidae, Evaniidae, Pelecinidae. Pars II. Breitkopf & Härtel, Leipzig. VIII + 1141. (distribution); Townes & Townes, 1962Townes, H.K. & M. Townes 1962. Ichneumon-flies of America north of Mexico: 3. Subfamily Gelinae, tribe Mesostenini. Bulletin of the United States National Museum 216 (3):1-602.:443 ( listed as synonym of Mesostenus gracilis Cresson, 1864); 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.:470 ( listed as synonym of Mesostenus gracilis Cresson, 1864).