Zethus strigosus Saussure, 1875:42, ♂♀.The Gulf side of Mexico. Orizaba (leg. Sumichrast). - Dalla Torre, 1894Dalla Torre, C.G. 1894. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus, IX. Vespidae (Diploptera). Guilelmi Engelmann, 181. (distribution); Zavattari, 1912Zavattari, E. 1912. Materialien für eine Monographie der Neotropischen Eumeniden. Archiv für Naturgeschichte 78:1-272. (distribution); West-Eberhard et al., 1995West-Eberhard, M.J., J.M. Carpenter & P.E. Hanson 1995. The vespid wasps (Vespidae). In: Hanson, P.E. & I.D. Gauld (Ed.). The Hymenoptera of Costa Rica. 561-587. (distribution); Carpenter et al., 2012Carpenter, J.M., B.R. Garcete-Barrett & Y.J.A.F. López 2012. Las Vespidae (Hymenoptera: Vespoidea) de Guatemala. In: Cano, E.B. & J.C. Schuster (Ed.). Biodiversidad de Guatemala. Volumen 2. 269-279. (distribution).
Zethus fortistriolatus Cameron, 1907:82, ♀. Holotype ♀, Nicaragua; Bequaert, 1928Bequaert, J.C. 1928. A study of certain types of diplopterous wasps in the collection of the British Museum. The Annals and Magazine of Natural History ser. 10: v. 2 (7):138-176.:157, Holotype ♀ (British Museum). Synonymized with Zethus strigosus Saussure, 1875 by Bequaert, 1928Bequaert, J.C. 1928. A study of certain types of diplopterous wasps in the collection of the British Museum. The Annals and Magazine of Natural History ser. 10: v. 2 (7):138-176.:156.