Two families of cicada (known as broods) will emerge simultaneously for the first time in over a century, causing a unique phenomenon across several US states. For the first time since 1803, two broods of cicadas, scientifically known as XIX and XIII, will come out of the ground screaming and flying simultaneously after more than a decade of eating to transform into adults.
There are seven species of periodical cicadas, including three that appear every 17 years and four that appear every 13, CBS News reported.
