Magicicadas surface only once every 13 or 17 years, depending on the species. Associated Press

In a few weeks, stretches of the Northeast and mid-Atlantic will become littered with big, noisy, red-eyed bugs emerging from the earth in unison like soldiers from an underground army.

There's no cause for alarm, though. These largely harmless insects, known as periodical cicadas, or magicicadas, are looking for love, not war.

"It's amazing to watch a cicada eclosion, which is when they emerge from the shell, because it's en masse," said Elias Bonaros, a cardiologist and self-described bug enthusiast who lives in Bayside, N.Y. "It's like a biblical plague that you can witness."

Although perhaps best known for their caterwaul choruses and the carcasses they leave behind, magicicadas generate a lot of curiosity because of their cyclical emergences. An emergence is when a throng of periodical cicadas rises from the ground as soon as the soil reaches about 64 degrees Fahrenheit. The groups of magicicadas, known as broods, surface only once every 13 or 17 years depending on the species.

This year marks the return of Brood II, known among some scientists as the East Coast Brood, which is concentrated between Connecticut and Northern Virginia. Operating on a 17-year cycle, Brood II last made an appearance in 1996, and before that in 1979.

Once Brood II arrives, the bugs get right down to business: mating. The males are known for their loud mating songs that sound like hissing chirps. Unlike crickets, which repeat just one call, a male magicicada must sing multiple songs in a specific sequence. Only then will he have a shot at attracting a female. If she is interested, she'll respond by flicking her wings, and the two conjugate.

Shortly after the female has laid eggs, she will die, then the male will. Six to eight weeks later, the eggs hatch and the nymphs will burrow into the ground, not to be seen for 17 more years.

"It's an exciting phenomenon," said John Cooley, a research scientist at the University of Connecticut who has been studying magicicadas since the early 1990s. "In Darwin's 'Theory of Evolution,' he argues that it is the exceptions that are the most fascinating to us because they reveal the most interesting elements of life. Periodical cicadas are in every way the exception."

Because periodical broods tend to emerge in the same locations each time, scientists can fairly accurately predict which areas will get hit the hardest.

"I don't mean to sound like a wizard or fortune teller, but Staten Island should strap in," said Mr. Cooley, who expects them to arrive in New York City around May 20. His logic is simple: That borough was overrun by Brood II in 1996.

That means it is likely to be a busy year for Ed Johnson, director of science at the Staten Island Museum, which, with about 35,000 specimens, said it boasts the largest cicada collection in North America.

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In 1996, Mr. Johnson fielded dozens of phone calls every day from people infuriated by magicicadas damaging their plants, screeching through the night and, eventually, blanketing their yard with dead carcasses.

"People would hold their phones to their yard and say, 'Listen to this! I can't take it anymore!' " he recalls. "And we'd just laugh and say, 'Well, they're going to die soon so you'll just have to wait.' "

And while the cicadas are largely harmless, some residents take issue with plant damage that can occur when the females slice into thin tree branches to safely lay dozens of eggs at a time. This can potentially weaken the tree.

"If you're really worried about it, a little netting will do the trick," Mr. Johnson advises.

This year, Mr. Johnson and his colleagues are helping Mr. Cooley with a long-term mapping project that plots the locations and concentrations of Brood II. As part of the museum's spring programming, employees will lead guided walks to teach people how to identify magicicadas and their songs. The hope is that the more people there are who can contribute cicada sightings, the more data they will collect.

The lingering question: Why does the process take 17 years?

"Man, I wish I knew," Mr. Cooley said. "The fact is, we're still working on good, testable hypotheses. We still have a lot of studying to do."

Write to Megan Buerger at