There's a buzz of talk about pesky insects that make a buzzing sound for real. They're known as cicadas (pronounced sih-KAY-duhz) -- 1 1/2-inch-long, slow-flying bugs with dark bodies and red eyes. Male cicadas are the noisy ones, sounding like a grass trimmer as they call to females. Scientists say the noise can reach 90 decibels — the same level as a lawnmower.

Unlike ordinary cicadas seen occasionally in mid-summer, these ones appear just once every 17 years along the East Coast. This year's have been underground since 1996, shortly after they hatched from eggs, squirmed into the dirt and began sucking fluid from tree roots. Now they're ready to produce the next generation. They'll emerge in states from North Carolina to Connecticut by early June, once the soil temperature reaches 64 degrees. Rare sightings have been reported as far west as Nebraska and central Kansas.

Some areas could have a couple million cicadas per street. (Yes, you read that right!) They don't bite or sting, but trees could lose small branches as they munch on leaves. For animals, they're a flying snack that's rich in protein. Birds, mice, raccoons, opossums and other animals eat cicadas. The spectacle, or nuisance, won't last long. Adults live only four to six weeks. But their 17-year life span after hatching makes them the longest-lived insects known.

Expert says: "They can't hurt you in any way. And they don't hurt animals." -- Dan Babbitt, insect specialist at the National Museum of Natural History in Washington, D.C.

Writer says: "Adult males are snapping rigid plates on their abdomens to produce their courtship song. The females are clicking their wings to signal approval." – Carl Zimmer, New York Times science columnist

Professor says: "We're talking about a boatload of cicadas. There could be as many as a billion cicadas per square mile." – Michael Raupp, University of Maryland