Imagines
Male cicadas (and only males) have loud noisemakers called “tymbals” on the sides of the abdominal base. Their “singing” is not stridulation as in many other familiar sound-producing insects like crickets (where two structures are rubbed against one another): the tymbals are regions of the exoskeleton that are modified to form a complex membrane with thin, membranous portions and thickened “ribs”. They rapidly vibrate these membranes with strong muscles, and enlarged chambers derived from the tracheae make their body serve as a resonance chamber, greatly amplifying the sound. Some cicadas produce sounds louder than 106 dB (SPL), among the loudest of all insect-produced sounds. (This amazing sound has frequently inspired haiku poets in Japan to write about them.) They modulate their noise by wiggling their abdomens toward and away from the tree that they are on.
From Wikipedia. All this mess to say that this morning I was waken up by the sound of cicadas. They’re quiet now.