One of the noisier scientific mysteries is about to be revisited as billions of cicadas are set to swarm the East Coast of the United States. The cicadas spent 17 years underground and will spend the spring eating and mating.

Cicadas spend much of their lives underground as nymphs. Right before they reach maturity, the cicadas burrow out of the ground and molt. Their developmental cycle, from nymph to adulthood, could last for years. Scientists have grouped cicades into "broods" based on the time spent underground. For the U.S., there are 14 broods of cicadas that spend 17 years underground and three broods that spend 13 years underground. Brood II is set to reach maturity in 2013 with billions of cicadas ready to swarm the East Coast.

Cicadas generally populate regions in Connecticut, Maryland., North Carolina, New Jersey, New York, Pennsylvania and Virginia. The last time the Brood II cicadas were seen was in 1996.

Emerging as adults, the main goal of billions of cicadas is to mate and produce offspring before dying. The cicadas will be easy to distinguish and do not bite humans. Speaking about the impeding influx of cicadas, Craig Gibbs, entomologist at the Wildlife Conservation Society's Queens Zoo, described the insects as having, “a very dark colored body. They have really bright red eyes, and they also have bright red wing veins,” reports CBS News.

The cicadas will spend between four to six weeks feeding and mating during mid-April until late May. Residents of the Brood II states should expect to see cicadas on a daily basis as there could be "millions of cicadas per square mile,” CBS News notes.

While cicadas are not pests to trees, and are harmless to humans, the male’s mating song can cause quite the racket. Cicadas have a specific song, similar to a rattling sound, which is used to attract mates. Male cicadas produce this song by using tymbals found on their abdomens, whereas crickets and other insects make their songs by rubbing their limbs together.

If the East Coast is experiencing a hot spring expect the cicadas to make plenty of noise. Residents of Brood II states should get use to the cicada symphony and, luckily, will not have to listen to billions of cicadas singing until 2030.

A video of Brood XIII cicadas invading Illinois can be viewed below.