Each year a type of cicada, called the annual cicada or "dogday harvestfly", emerges from the ground into its adult form (photo above right). While this insect is very short lived as an adult (adult cicadas have no mouths and never even eat in that form), the sound they make to communicate with other cicadas is the distinctive, loud whining sound that's heard when the weather warms. After mating, the adult cicadas lay their eggs in small branches of trees, and when the eggs emerge the nymphs burrow back into the ground to eat and develop until they emerge from the ground to become adults after about three years.
You may actually find evidence of these noisy visitors in your yard. Late on summer evenings, nymphs may be spotted on the trunks or branches of trees as they climb from the ground to emerge as adults. During the day, the exoskeletons (shells) of the nymphs that have already become adults (photo above left) often be found still stuck to trees, under trees in lawns, or on other rough surfaces in the yard. Finally, you may even get to see the adult insect in its final form as it moves through the area searching for a mate. While they can look a little frightening, remember that they do not bite or sting.
For more information on "dogday harvestflies", as well as facts about periodic cicadas that emerge only every 17 years in well-choreographed broods, click here to visit National Geographic's page on these fascinating insects.