We must be having a good year for them, the noise is deafening under this row of Poplars. I can't imagine how many there are in the trees.
They live under ground as nymphs for up to 3 years shedding their skin as they grow. Then one night they burrow out and climb onto a post or tree trunk for the final shed. We see lots of these empty cases around. They fly off in the morning and after mating the females lay their eggs on grasses or trees. The adults live for 2 to 4 weeks.
This is one of the male Chorus Cicadas who was busy singing his heart out while I took this photo.