They serve as good fish bait and can even be frozen. Also, many dogs and cats, alerted by the activity, quickly develop a taste for cicada snacks. Although cicadas don't bite or sting, they have one defense mechanism you should know about. When disturbed, as they fly away they shoot liquid excrement in your general direction. That may be what you felt on your forehead yesterday afternoon as you walked under a tree.
Nature works in mysterious ways.
Like the pod people in Invasion of the Body Snatchers , each cicada leaves behind the hollow, lifeless shell of its former body. No doubt you have seen your share of the grotesque mementos clinging to tree trunks, telephone poles, the sides of buildings, even road signs. They're piled as thick as mulch around the roots of some trees. If you bother to look at the papery husks, you'll see, through the slit in the back, what look like white threads. These are the tubes that allowed the cicada to breathe.