In one of nature’s mysteries, 15 states will soon witness the reemergence of Brood X — or the Great Eastern Brood — of periodical cicadas. These “large, winged, kind of scary-looking but mostly harmless flying insects known for their almost deafening buzz” emerge in-unison every 17 years. Periodical cicadas have “black bodies and bold red eyes,” and spend 17 years lying underground in “wingless nymph form,” feeding on sap. While most cicadas travel as individuals or in small groups after reaching adulthood, periodical cicadas follow a strict schedule... “The end of May through June, it can get pretty loud —...