Cicada

The adult insect, known as an imago, is 2 to 5 centimetres (0.79–1.97 in) in total length in most species. The "singing" of male cicadas is not stridulation such as many familiar species of insects produce — for example crickets. Instead male cicadas have a noisemaker called a tymbal below each side of the anterior abdominal region. The tymbals are structures of the exoskeleton formed into complex membranes with thin, membranous portions and thickened ribs. Contraction of internal muscles buckles the tymbals inwards, producing a click; on relaxation of the muscles the tymbals return to their original position, producing another click. The male abdomen is largely hollow, and acts as a sound box. By rapidly vibrating these membranes a cicada combines the clicks into apparently continuous notes, and enlarged chambers derived from the tracheae serve as resonance chambers, with which it amplifies the sound