Giant Brood of Billions of Insects Set to Emerge in US in Mass Synchronized Event JOHN COOLEY & CHRIS SIMON, THE CONVERSATION 15 MARCH 2021 A big event in the insect world is approaching. Starting sometime in April or May, depending on latitude, one of the largest broods of 17-year cicadas will emerge from underground in a dozen states, from New York west to Illinois and south into northern Georgia. This group is known as Brood X, as in the Roman numeral for 10.
For about four weeks, wooded and suburban areas will ring with cicadas' whistling and buzzing mating calls. After mating, each female will lay hundreds of eggs in pencil-sized tree branches.