luck. they're back. those giant orange bug-eyed winged creatures that sing. in just a few weeks states from connecticut to north carolina, watch out. you'll be swarming with cicadas. >> when some part of the country almost any given year there is a brood of cicadas. >> michael raupp is a professor of entomology at the university of maryland. basically he studies bugs. how many cicadas are we talking here? >> we're talking about a boatload. there could be as many as a billion cicadas per square mile. >> reporter: different types of cicadas appear every summer, but this spring a group known as brood 2 will be back after 17 years. that sound is the cicadas' mating call. they sing, mate, lay eggs, and then die in trees all in just four to six weeks. well, i read earlier today that what we're going to see for four to six weeks when they crop up