(KTAL/KMSS) — The U.S. Food and Drug Administration is warning people to not eat cicadas if they are allergic to seafood.

“Yep! We have to say it!” the FDA said on their Twitter account Wednesday morning.

“Don’t eat #cicadas if you’re allergic to seafood as these insects share a family relation to shrimp and lobsters.”

The cicada invasion this year only happens once every 17 years. For almost two decades, they have been maturing underground, sucking sap from tree roots. Now millions of insects are set to burst forth once the days are consistently 64 degrees or warmer for several weeks.

The Brood X is the biggest of the 17-year cicada broods, according to Cicada Safari, which says they occur in parts of 15 eastern states from Indiana to Georgia to New York.