Periodical cicadas, which include 13-year broods and 17-year broods, belong to the scientific name Magicicada. There are actually 3 species of 17-year cicadas coming out together this May. They look almost the same to us but the males of each species have a different mating call. With all the racket they'll be making it is difficult for us (but not the cicadas) to hear the separate calls. The best way to identify the species is to look on the underside: Magicicada septendecim has fairly broad orange bands on each segment, Magicicada septendecula has narrow orange bands, and Magicicada cassini is almost entirely black underneath.