An order that includes over 20,000 species of terrestrial insects, including most of the “singing” insects, some of the world's largest insects, and some well-known pests. Most species of Orthoptera (from “orthos,” meaning straight, and “pteron,” meaning wing) have enlarged hind legs adapted for jumping. These include grasshoppers and locusts (in the suborder Caelifera, a mainly diurnal group); and the crickets, katydids (bush-crickets), New Zealand weta, and allied families (suborder Ensifera, which comprises mainly nocturnal species). Orthoptera share with other orthopteroid insects, such as mantids and stick insects (now in separate orders Mantodea and Phasmatodea), gradual metamorphosis, chewing mouthparts, and two pairs of wings, the anterior pair of which is usually thickened and leathery and covers the fanwise folded second pair. Wings are reduced or absent in many species. Characters that define the Orthoptera as a natural group (the inclusive set of all species stemming from a common ancestor) are the jumping hind legs, small and well-separated hind coxae (basal leg segments), a pronotum with large lateral lobes, and important molecular (genetic) characters. Food habits range from omnivorous to strictly carnivorous or herbivorous. Habitats are nearly all terrestrial, including arctic-alpine tundra and tropical areas with aquatic floating plants. Female orthopterans usually lay their eggs into soil or plant material. There are no parasitic species, but a few crickets live as cleptoparasitic “guests” in ant nests.