Anderson sent this:

My dog found the Cicada in the attached photos about 10 minutes ago. I grabbed the camera and took several photos. It is a Dogday Harvestfly Cicada. Even now I can hear more of them in the trees out front. The term "Dogday" comes from the fact that these cicadas are more often than not found during the dog days of summer, or the warmest time of the year. I'm quite sure these are the cicadas that most people are hearing right now, and are also responsible for the shells that are being found. As you recall, in 2007 we had the cicada hatch in May and they were all gone by this time of year.

He hopes to put up high rez pics on his site, Catch Photo Release Fishing, today. His site is worth visiting for many reasons, but especially if you like photos of fish.

The University of Illinois Extension has a nice breakdown of the difference between annual and periodical cicadas. In 2007, the Chicago area had its last emergence of periodical cicadas.

The old-time IDNR guy sent this:

The cicadas you are seeing are Annual cicadas (dark green in color). [See Anderson's photo above.] They are present each year. The Periodical cicadas are orange in color and only occur every 17 or 13 years. I have exoskeletons (shells) all over miy trees in my yard where they have molted into their flying, mating, and final stage.

Cool insects. I love to sit and listen to them each evening. However, when a brood of periodicals emerges, the sound becomes deafening.

I like that image of sitting and listening to cicadas.