Watch: Cicadas appear on trees in parts of US

The cicadas have arrived! 

Video shared of cicadas stuck to tree trunks have begun circulating on social media as the emergence of two broods begins. 

Billions, if not trillions, of these critters will engage in a frantic mating frenzy that will last several weeks before they eventually die. 

But that’s not before they lay eggs on forest floors and the cycle of life begins anew. 

Still image taken from video showing cicadas on trees in parts of the U.S.  (Brad Buchanan via Storyful)

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2 broods

It will be the first time in 221 years that two types of cicadas -- brood XIX and XIII -- have risen from the ground at the same time, back when Thomas Jefferson was president, and it is not expected to happen again until 2244. 

Most cicada species come out every year, but in the United States, there are two periodical broods of cicadas that stay underground for either 13 years or 17 years. 

Brood XIII cicadas appear on a 17-year cycle, and are restricted mostly to northern Illinois, eastern Iowa, southern Wisconsin and a few counties in extreme northwestern Indiana, according to entomologist Floyd Shockley of the Smithsonian Institution's National Museum of Natural History in Washington. 

Brood XIX emerges on a slightly shorter 13-year cycle, and are widely distributed from Alabama, Arkansas, Georgia, Indiana, Illinois, Kentucky, Louisiana, Maryland, Missouri, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee and Virginia - a total of 15 states, according to Shockley. The two broods together span parts of 17 states. 

The emergence is not simultaneous and started in April in southern locales and is expected to begin in June in more northern areas. 

FOX News and Storyful contributed to this report. This story was reported from Los Angeles.