For the past several nights these cicadas have been exuviating from their larval skins on the Norway spruces and white pines in our yard. The larvae spend about 3 years underground feeding on sap through tree roots. When they emerge they climb up the trees and latch onto the bark. The skin over their back splits and the adult emerges with its wings looking like tiny colorful petals. They pump fluid into the wings to expand them and spend the next few hours drying and hardening and by morning are gone leaving the exuviae behind.