Pacific beetle mimic cockroach Diploptera punctata sprays a noxious chemical, intended to deter predators, from internal pouch on left side of body leaving dark spots on indicator paper, as its left rear leg is pinched by scientist in laboratory demo. This cockroach also has a pouch on its left side which would be used if a predator were to attack from that side. Many insects and other arthropods use a variety of chemical defences to ward off predators. The Pacific beetle mimic cockroach is approximately 25 cm in length and is found in Asia and the Pacific, including Hawaii.