Cracker butterfly

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Cracker butterfly

Female Hamadryas velutina

Scientific classification

Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Nymphalidae
Subfamily:	Biblidinae
Tribe:	Ageroniini
Genus:	Hamadryas Hübner, 1806

Cracker butterflies are a neotropical group of medium-sized butterfly species of the genus Hamadryas. They acquired their name due to the unusual way that males produce a "cracking" sound as part of their territorial displays.

Contrary to earlier erroneous supposition that the sound was produced by the male genitalia, the sound is produced by swollen veins in the forewings which strike one another if the male forces the wing upstroke to maximum amplitude. The females lack this sound-producing mechanism.

Nearly all species in the genus are fairly cryptic in their dorsal coloration, and they are fond of resting on trees, boulders, and other such surfaces against which they are camouflaged. Because of this coloration, these butterflies ares also colloquially known as Calico butterflies.

Research has also shown that cracker butterflies can also detect the sounds made by other butterflies, which would be a form of aural communication.^[1]The organ of hearing is believed to be Vogel's organ, located at the base of the forewing subcostal and cubital veins ^[2]