REGION — The last time the group of cicadas know as Brood II appeared in the region was 1996. The insects in Brood II are 17-year-cicadas, not locusts as they are sometimes called, and if you do the math you’ll know that it’s time for them to emerge from their underground homes once again.

In May or June, depending on the weather, swarms of billions of the insects will fly to the treetops in the Northeast U.S. The males will make noise that is attractive to the females and annoying to some humans.

The insects will be in several states including New York, New Jersey and Pennsylvania. But fear not—the National Pest Management Association says that while cicadas are considered a nuisance, they don’t bite or sting and don’t pose much of a threat to humans. However, when the females are laying their eggs in twigs, they can cause damage to ornamental trees.

These particular cicadas are the longest-living insects in North America, and spend most of their long lives underground mostly eating fluids from tree roots. Then, in year 17, the mature cicada nymphs emerge in tremendous numbers and are active for about four to six weeks of mating and laying eggs.

The adults then die off, and another generation will not be seen again for another 17 years.