Cryptus extrematis Cresson, 1864:304, ♂♀. ♂, ♀, Mass. (leg. Sanborn); ♂, ♀, Penn. (leg. Auxer); ♂, ♀, Delware (leg. Dr. 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.:87, Type ♀ (Philadelphia). - Cresson, 1872Cresson, E.T. 1872. Hymenoptera Texana. Transactions of the American Entomological Society 4:153-292. (distribution). - As Gambrus extrematis: - 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). - As Ichneumon extrematis: - 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.:502 ( listed as synonym of Vulgichneumon brevicinctor (Say, 1825)).
Cryptus samiae Packard, 1865:345, Lectotpye ♀ (Cambridge), designated by 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.:87. - 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.:87 ( listed as synonym of Gambrus extrematis (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.:449 ( listed as synonym of Gambrus extrematis (Cresson, 1864)).
Echthrus Provancheri Provancher, 1885:116, 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.:87, Lectotpye ♀ (Quebec). - 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.:87 ( listed as synonym of Gambrus extrematis (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.:449 ( listed as synonym of Gambrus extrematis (Cresson, 1864)).
Spilocryptus cecropiae Habermehl, 1919:239 - 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.:87 ( listed as synonym of Gambrus extrematis (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.:449 ( listed as synonym of Gambrus extrematis (Cresson, 1864)).