While it’s not quite the swarm of locusts of Biblical lore, this year’s appearance of the Brood II periodical cicada is sure to be a big one. From Connecticut to Virginia, these bugs will be out and about, covering any vertical surface they can find and filling the air with their distinctive chorus.

Periodical cicadas are cicadas of six species in the genus Magicicada, and they all mature in the same year in the same part of the country. Cicadas that follow a 13-year cycle are more concentrated in the southern and midwestern United States, while the 17-year cicadas are more prevalent in the northeast. Because different areas have cycles at different times, each “batch” of cicadas is called a brood; this year’s brood is Brood II, and last year’s cicadas, which were Brood I, surfaced in Virginia and Tennessee.

This spring, little cones of dirt will start appearing in the ground as cicada nymphs dig themselves out after 17 years of development underground. When they do emerge at sunset, they’ll chill out on some nearby greenery for a few days as their exoskeletons finish hardening. Adult male cicadas will then aggregate into choruses to call for females

Cicadas can’t bite or sting, and they’re not poisonous, so unless they mistake your arm for a tree branch and start nibbling on your arm in an attempt to find plant fluids, they aren’t harmful. Orchard keepers tend not to be huge fans of the insects because they will break off twigs just from the sheer weight of so many on one part, and the constant ringing of their choruses may become tiring for some.

Though they are a nuisance to some, periodical cicadas are a neat occurrence, so keep an eye out for them if you’re in the Northeast this summer.