A large order of exopterygote insects containing the grasshoppers, locusts, crickets, and—in some classification systems—the cockroaches (see dictyoptera). They are characterized by enlarged hind legs modified for jumping and biting mouthparts and produce sounds by stridulation. The crickets and long-horned grasshoppers (e.g. Gryllus, Tettigonia) have long threadlike antennae and stridulate by rubbing together modified veins on their forewings. The hearing organs are on the front legs. The short-horned grasshoppers and locusts (e.g. Chorthippus, Locusta) have short antennae and stridulate by rubbing pegs on the hind leg against a hardened vein on the forewing. The hearing organs are on the abdomen.