ORTHOPTERA, the term used in zoological classification for that order of insects which includes the cockroaches, mantids, grasshoppers, locusts, crickets and their allies. The earwigs are included here by some authorities but they are now more often relegated to a separate order of their own—the Dermaptera (see EARWIG). The Orthoptera are essentially terrestrial insects and many possess greatly developed powers of running or leaping. Ex cepting in the Acridiidae, flight is not one of their striking charac teristics and wings are often reduced or entirely lost. They are mostly insects of comparatively large size, some being among the giants of their class; many possess well-developed sound-produc ing organs and are notorious stridulators. The wings, when pres ent, are net-veined, the anterior pair being more or less hardened to form tegmina which are narrower than the membranous hind wings; the latter have a well developed posterior lobe capable of being folded up fanwise. The antennae are most often long and
threadlike, the mouth parts are of the biting type and have a 4 lobed ligula. The prothorax is generally large and the abdomen is terminated by a pair of cerci. Metamorphosis is incomplete and in the wingless forms it is very little evident. Over 13,000 species of Orthoptera are known and of these about 500 inhabit Europe. In Britain there are 31 indigenous forms, while some others are naturalized alien species ; there are also a number of casual immi grants which have not become established.
Orthoptera may be conveniently divided into forms which run or walk (Cursoria) and into those which leap (Saltatoria) as given below.