A cicada invasion that is expected to engulf much of the United States’ Atlantic seaboard over the next few weeks touched off this week in North Carolina. The “Swarmagaddon,”as some are calling it, will comprise billions of the bugs and will affect areas from North Carolina to Connecticut. Maryland, Virginia, New Jersey, New York, and Pennsylvania will also see their share of the bugs.

Brood II is one of the 15 cicada “broods” that are distributed across the eastern half of the United States. Every brood’s constituent bugs spend most of their lives in underground burrows, where they live off of plant roots.

But every 13 or 17 years—one or the other, depending on the brood—the entire brood lifts up to the surface to roost on above-ground bush and tree branches to finish off their lives in a massive mating season.