Crabro ezræ Cameron, 1904:266, ♀.Mexico; Leclercq, 2000Leclercq, J. 2000. Hyménopteres Sphécides Crabroniens des Amériques du genre Crossocerus Lepeletier & Brullé, 1835. Notes fauniques de Gembloux 40:3-75.:66, Holotype ♀ (London). Synonymized with Crossocerus spinigerus (Cameron, 1904) by Leclercq, 2000Leclercq, J. 2000. Hyménopteres Sphécides Crabroniens des Amériques du genre Crossocerus Lepeletier & Brullé, 1835. Notes fauniques de Gembloux 40:3-75.:66. - Amarante, 2005Amarante, S.T.P. 2005. Addendum and corrections to a synonymic catalog of Neotropical Crabronidae and Sphecidae. Papéis Avulsos de Zoologia 45 (1):1-18.:5 ( listed as synonym of Crossocerus spinigerus (Cameron, 1904)). - As Crossocerus ezrae: - 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).
Rhopalum spinigerus Cameron, 1904:263, ♂.Mexico; Leclercq, 2000Leclercq, J. 2000. Hyménopteres Sphécides Crabroniens des Amériques du genre Crossocerus Lepeletier & Brullé, 1835. Notes fauniques de Gembloux 40:3-75.:66, Holotype ♂ (London). - As Crossocerus spiniger: - 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). - As Crossocerus spiniger: - 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). - As Crossocerus spinigerus: - Leclercq, 2000Leclercq, J. 2000. Hyménopteres Sphécides Crabroniens des Amériques du genre Crossocerus Lepeletier & Brullé, 1835. Notes fauniques de Gembloux 40:3-75. (distribution); Amarante, 2005Amarante, S.T.P. 2005. Addendum and corrections to a synonymic catalog of Neotropical Crabronidae and Sphecidae. Papéis Avulsos de Zoologia 45 (1):1-18. (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). - As Rhopalum spiniger: - As Rhopalum spiniger: