Each year, somewhere in the United States east of the Rocky Mountains, a brood of the periodical cicadas (Magicicada septendecim) emerges. Periodical cicadas have two distinct races based on required time to complete their life cycle: a 17-year northern race and a 13-year southern race. In each race there are three distinct species. The 17-year periodical cicada is the most common and longest-lived of this insect. The northern third of Illinois is in the range Brood XIII, which last appeared in 2007. Its next appearance is due in 2024.
There are two kinds of cicadas in Northern Illinois, the annual or “dog day” cicada and the periodical cicada. The shiny, jet-black periodical cicadas have burnt orange transparent wings, bright red eyes, and are about 1 1/2 inches long.
The annual cicadas are green to black in color with transparent silvery wings and are nearly double in size to the periodical cicadas. They appear each year from July to September. The black eyes of the annual cicada distinguish them from the red-eyed periodical cicada. Both types of cicadas are harmless to humans except their sound may be a minor nuisance.