For the first time in 220 years, 17- and 13-year cicadas will emerge together. Millions could come to Wisconsin

There are many types of cicadas in North America. Some emerge every year, often in July and August. These cicadas have life cycles of about 2-3 years, PJ Liesch, extension entomologist and director of the University of Wisconsin-Madison’s Insect Diagnostics Lab, told the Journal Sentinel.