Rhopalum gracile Wesmael, 1852
Rhopalum nigrinum von Kiesenwetter, 1849: 91 . Germany: Sachsen-Anstalt, Eisleben (syntype ♀ ♂).
Rhopalum gracile Wesmael, 1852: 592 . Switzerland: Genève area (Bruxelles) (holotype ♀).
Crabro kiesenwetteri A. Morawitz, 1866: 267 .
Corynopus simplicipes F. Morawitz, 1888: 291 . Uzbekistan: Zeravshan (Lectotype ♂).
Distribution: Nearctic and Palearctic regions.