Larra rufitarsis Cameron, 1889:50, ♂. ♂, Mexico, Presidio (leg. Forrer); 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.:172, Holotype ♂ (BMNH). 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. - Cameron, 1888-1900Cameron, P. 1888-1900. Biologia Centrali-Americana - Insecta. Hymenoptera. (Fossores) Vol. II. R. H. Porter and Dulau & Co., London. 413pp, 14 pl.:50 (listed); Dalla Torre, 1897Dalla Torre, C.G. 1897. Catalogus hymenopterorum hucusque descriptorum systematicus et synonymicus. Volumen VIII: Fossores (Sphegidae). Breitkopf & Härtel, Leipzig. 1-749. (distribution); 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.:172 ( listed as synonym of Tachysphex aequalis Fox, 1894); Amarante, 2002Amarante, S.T.P. 2002. A synonymic catalog of the neotropical Crabronidae and Sphecidae (Hymenoptera: Apoidea). Arquivos de Zoologia (São Paulo) 37:1-139.:34 ( listed as synonym of Tachysphex apicalis Fox, 1893).
Tachysphex æqualis Fox, 1894:517, ♂.State of Washington; 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.:174, Lectotype ♂ (ANSP). 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. - Dalla Torre, 1897Dalla Torre, C.G. 1897. Catalogus hymenopterorum hucusque descriptorum systematicus et synonymicus. Volumen VIII: Fossores (Sphegidae). Breitkopf & Härtel, Leipzig. 1-749. (distribution); 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), 172 (revised status); Amarante, 2002Amarante, S.T.P. 2002. A synonymic catalog of the neotropical Crabronidae and Sphecidae (Hymenoptera: Apoidea). Arquivos de Zoologia (São Paulo) 37:1-139. (distribution); Nava-Bolaños & Osorio-Olvera, 2022Nava-Bolaños, A. & L. Osorio-Olvera 2022. Estado del arte del conocimiento de biodiversidad de los polinizadores de México. Revista Mexicana de Biodiversidad 93:1-77. (distribution).
Tachysphex opwanus Rohwer, 1911:574, 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.:174, Holotype ♂ (USNM). 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.:174 ( listed as synonym of Tachysphex aequalis Fox, 1894); Amarante, 2002Amarante, S.T.P. 2002. A synonymic catalog of the neotropical Crabronidae and Sphecidae (Hymenoptera: Apoidea). Arquivos de Zoologia (São Paulo) 37:1-139.:34 ( listed as synonym of Tachysphex aequalis Fox, 1894).
Tachysphex washingtoni Rohwer, 1917:172, 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.:174, Holotype ♀ (USNM). 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.:174 ( listed as synonym of Tachysphex aequalis Fox, 1894); Amarante, 2002Amarante, S.T.P. 2002. A synonymic catalog of the neotropical Crabronidae and Sphecidae (Hymenoptera: Apoidea). Arquivos de Zoologia (São Paulo) 37:1-139.:34 ( listed as synonym of Tachysphex aequalis Fox, 1894).