 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.Charles W. Holliday and Joseph R. Coelho devised a new key in 2004 to identify the "Sphecius" species, examining 4,451 wasps among the five New World species, and noting that 98% of the female "S. convallis" wasps examined had yellow markings on gastral tergites one to four (or fewer) and "S. grandis" had 98% yellow markings from tergites one to five (or more).The 2% percent of "S. grandis" that overlapped with "S. convallis" were determined by density of the punctation in colour of the first tergum against the second.