"Sphecius grandis" can be distinguished from "S. convallis" (the Pacific cicada killer wasp) by the coloration pattern of the gastral tergites.Formerly, the two species were distinguished on the basis of the number of tergites with yellow markings (five in "S. grandis" and three in "S. convallis"), but a more recent study showed that this character was insufficient to distinguish the two species.