WASHINGTON – Any day now, billions of cicadas with bulging red eyes will crawl out of the earth after 17 years underground and overrun the East Coast. The insects will arrive in such numbers that people from North Carolina to Connecticut will be outnumbered roughly 600-to-1. Maybe more.

Scientists even have a horror-movie name for the infestation: Brood II. But as ominous as that sounds, the insects are harmless. They won't hurt you or other animals. At worst, they might damage a few saplings or young shrubs. Mostly they will blanket certain pockets of the region, though lots of people won't ever see them.

"It's not like these hordes of cicadas suck blood or zombify people," said May Berenbaum, a University of Illinois ­entomologist.

They're looking for just one thing: sex. And they've been waiting quite a long time.

Since 1996, the 1-inch bugs in this batch, in wingless nymph form, have been a few feet underground, sucking on tree roots and biding their time. They will emerge only when the ground temperature reaches precisely 64 degrees. After a few weeks up in the trees, they will die and their offspring will go underground, not to return until 2030.

"It's just an amazing accomplishment," Berenbaum said. "How can anyone not be impressed?"

And they will make a big racket, too. The noise all the male cicadas make when they sing for sex can drown out your own thoughts, and maybe even rival a rock concert. In 2004, Gene Kritsky, an entomologist at the College of Mount St. Joseph in Cincinnati, measured cicadas at 94 decibels, saying it was so loud "you don't hear planes flying overhead."

There are ordinary ­cicadas that come out every year worldwide, but these are different. They're called magicicadas — as in magic — and are red-eyed. And these magicicadas are seen only in the eastern half of the United States, nowhere else in the world.

There are 15 U.S. broods that emerge every 13 or 17 years, so that nearly every year, some place is overrun. Last year it was a small area, mostly around the Blue Ridge Mountains of Virginia, West Virginia and Tennessee. Next year, two places will get hit: Iowa into Illinois and Missouri; and Louisiana and Mississippi. And it's possible to live in these locations and actually never see them.

This year's invasion, Brood II, is one of the bigger ones.