Tymbal

In male cicadas, the tymbals are membranes in the abdomen, responsible for the characteristic sound produced by the insect.

In tiger moths, the tymbals are modified regions of the thorax and produce high-frequency clicks.

In lesser wax moths the left and right tymbals emit high-frequency pulses that are used as mating calls.

The tymbals of a tiger moth are specialized regions on the metathoracic episterna, normally corrugated such that sound is produced when the entire tymbal surface is buckled by muscular contraction and then released, producing a series of extremely rapid "clicks" as the corrugations flex back into place.

[3] These sounds are only occasionally audible to humans, and are used in both acoustic aposematism (the moths are advertising to bats that they are toxic[4]), and as mating signals.

Cicada tymbals: sound-producing organs and musculature.
  1. Body of male Cicada from below, showing cover-plates of sound-producing organs
  2. From above showing tymbals (drums), natural size
  3. Section showing muscles which vibrate tymbals (magnified)
  4. A tymbal at rest
  5. A tymbal thrown into vibration (as when cicada is singing), more highly magnified