 Distinguishing S. grandis from the other four New World species of Sphecius (S. convallis, S. hogardii, S. speciosus, S. spectabilis) is difficult. The female S. convallis was originally distinguished from the female S. grandis by the yellow marks from the first to third gastral tergites on S. convallis and yellow marks on all tergites for S. grandis. However, this was found to be insufficient for correct identification because the positions of the markings can vary among different wasps of the same species.
