Cicadas are winged insects, known for the songs sung by most, but not all, males of the species. They are better known for their swarming behavior which occurs every 13 to 17 years, depending on thee brood, or generation. There are 23 broods in North America, with the Maryland, Virginia, Ohio, Kentucky, Indiana, Illinois, D.C., Tennessee, and Georgia scheduled to see another visit from Brood X (a 17-year variety) in 2021.