Billions of cicadas will emerge in the US this year in a rare double-brood event

It’s official: 2024 belongs to the cicadas.

This spring, two different broods of cicadas — one that lives on a 13-year cycle and the other that lives on a 17-year cycle — will emerge at the same time from underground in a rare, synchronized event that last occurred in 1803.

Billions of the winged insects will make an appearance across the Midwest and the Southeast, beginning in some places in late April, for a raucous mating ritual that tends to inspire fascination and annoyance in equal measure.

This year’s dual emergence is a once-in-a-lifetime event. While any given 13-year brood and 17-year brood can occasionally emerge at the same time, each specific pair will see their cycles aligned only once every 221 years. What’s more, this year’s cicada groups, known as Brood XIII and Brood XIX, happened to make their homes adjacent to one another, with a narrow overlap in central Illinois.

“Thomas Jefferson was president the last time these two broods came out, so is it rare? Yes,” said Gene Kritsky, an entomologist at Mount St. Joseph University in Cincinnati and author of “A Tale of Two Broods,” a book about this year’s dual emergence that was published earlier this month.

Read the full story on NBCNews.com here.