A few weeks ago, Michelle Watson woke up to a deafening, steadily oscillating screech. “What the heck is that noise?” she wondered.

She went outside to her yard and saw hundreds of beady-eyed insects enrobed in a thick shell of gold emerging out of the ground and crawling up the trees. What Watson was seeing was the emergence of thousands of Brood X cicadas, part of a billions-strong insect swarm that has lain dormant for 17 years before arising to “scream,” mate— all over about three thunderous weeks.