An extremely large order, with 117 families and just under 25,000 species described in Australia. Extremely variable in size (0.4 to 80mm) and colour, but usually typified by modified, hardened forewings (elytra), designed to cover and protect the membranous hindwings, which are folded underneath when at rest. Elytra form a straight midline down the body when at rest and are not used in flight, instead being held away from the beating hindwings. In some species the forewings are reduced and some species are wingless. All stages of development have chewing (mandibulate) mouthparts. Sexual dimorphism apparent in many species, and extreme variations in shapes of body parts not uncommon.