any of a group of moths (order Lepidoptera) that are characterized by projecting wing tufts in the adult and dorsal humps in the larva. The nocturnal moths have stout, hairy bodies and somewhat narrow forewings. Most species are dull gray, yellow, or brown and are difficult to see (cryptic) on bark or twigs.

Larvae feed on foliage. When disturbed, some raise both ends of their bodies, vibrate their prolegs to frighten the enemy, and squirt a fluid to a distance of several centimetres. The bright coloration of the larva warns predators of its bad taste. Pupation occurs underground.