Adults have soft, narrow bodies with four delicately veined, lacy-looking wings that fold rooflike over the body when at rest. They are most commonly pale green, but some species are tan or brown. The eyes are coppery or golden. The antennae are long and threadlike. Flight is fluttery and slow. When handled, they can emit a foul odor.
Larvae are long, flattened, segmented, and lizard-like, with six legs. Impressive, sickle-shaped mandibles constitute the mouthparts. Larvae usually have camouflage patterns in gray, tan, and brown, and usually have small bristles on their bodies. Some species decorate their backs with debris for additional camouflage. At least one species glues deflated aphid skins onto its back.