any of about 30 species of flat, green insects (order Phasmida) that have a leaflike appearance. The female has large leathery forewings (tegmina) that lie edge to edge on the abdomen and resemble, in their vein pattern, the midrib and veins in a leaf. Females are flightless and so the hindwings have no function. The male has small tegmina and ample, non-leaflike, functional hindwings. Newly hatched young are reddish in colour and become green after feeding on leaves. Colour and form provide protection by allowing these insects to blend with their environment.