The goliath stick insect is one of Australia's largest phasmids. It is green with some yellowish patches on the head, thorax and legs. The wings are green with red markings on the underside. underneath. Both adults and nymphs are well camouflaged. When disturbed they will open their wings showing the red underside and make a hissing sound. Males are fairly slender with fully developed wings and can fly. Females are very bulky, and do not have large enough wings for flight, although they can spread their wings and glide a bit if they fall. Goliath nymphs are brown and have a stick like appearance.