; class Insecta, subclass Pterygota)
Order of endopterygote insects which have simple, biting mouth-parts. The antennae are conspicuous and multi-segmented, and the two pairs of large, equal or subequal wings are lace-like, divided into many small cells by numerous cross-veins. The larvae are predacious or parasitic, with distinctive, sickle-shaped, sucking jaws. Pupation occurs in a silken cocoon. The silk is produced from modified excretory tubules opening into the hind gut of the larva and is extruded from the anus, rather than being produced by salivary glands. Many species are highly coloured and patterned, sometimes with dense hairs, and most can be recognized by the highly branched terminal portions of the main veins (end-twigging). With the exception of the Hymenoptera, few other insect groups are more beneficial to humans, since adults and larvae are predacious on a vast range of sap-sucking insects (e.g. aphids and psyllids), and others on lepidopteran eggs and larvae, mites, and immature dipterans. The order is represented in all the major zoogeographical regions of the world.
Subjects: Zoology and Animal Sciences.