Tachysphex robustior Williams, 1914:164, Pulawski, 1988Pulawski, W.J. 1988. Revision of North American Tachysphex wasps including Central American and Caribbean species (Hymenoptera: Sphecidae). Memoirs of the California Academy of Sciences 10:1-211.:176, Holotype ♂ (KU). Synonymized with Tachysphex mundus Fox, 1894 by 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.:1632. - Pulawski, 1988Pulawski, W.J. 1988. Revision of North American Tachysphex wasps including Central American and Caribbean species (Hymenoptera: Sphecidae). Memoirs of the California Academy of Sciences 10:1-211. (distribution), 176 (revised status).
Tachysphex crenuloides Williams, 1914:168, Pulawski, 1988Pulawski, W.J. 1988. Revision of North American Tachysphex wasps including Central American and Caribbean species (Hymenoptera: Sphecidae). Memoirs of the California Academy of Sciences 10:1-211.:176, Holotype ♀ (KU). Synonymized with Tachysphex mundus Fox, 1894 by 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.:1632. - Pulawski, 1988Pulawski, W.J. 1988. Revision of North American Tachysphex wasps including Central American and Caribbean species (Hymenoptera: Sphecidae). Memoirs of the California Academy of Sciences 10:1-211.:176 ( listed as synonym of Tachysphex robustior Williams, 1914).