Brood X cicadas require 17 years to complete their development. When they emerge this year, they ll buzz and sing a chorus so loud, it can reach as high as 100 decibels. Ed Reschke/Getty Images
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.