Scientists and ordinary people with a bug fetish travel to see them. Thomas Jefferson once wrote about an invasion of this very brood at Monticello, his home in Virginia.
While they stay underground, the bugs aren't asleep. As some of the world's longest-lived insects, they go through different growth stages and molt four times before ever getting to the surface. They feed on a tree fluid called xylem. Then they go aboveground, where they molt, leaving behind a crusty brown shell, and grow a half-inch bigger.
The timing of when they first come out depends purely on ground temperature. That means early May for southern areas and late May or even June for northern areas.
The males come out first — think of it as getting to the singles bar early, Raupp says. They come out first as nymphs, which are essentially wingless and silent juveniles, climb on to tree branches and molt one last time, becoming adult winged cicadas. They perch on tree branches and sing, individually or in a chorus. Then when a female comes close, the males change their song, they do a dance and mate, he explained.
The males keep mating ("That's what puts the 'cad' in 'cicada,'" Raupp jokes) and eventually the female lays 600 or so eggs on the tip of a branch. The offspring then dive-bomb out of the trees, bounce off the ground and eventually burrow into the earth, he says.
"It's a treacherous, precarious life," Raupp says. "But somehow they make it work."