THYSANOPTERA, the name used in zoological classifica tion for a small order of the class Hexapoda commonly known as thrips. The majority of these creatures are very small, varying in length from h to of an inch, and they are mostly yellow, yellow brown or black in colour. They are found among all kinds of grow ing vegetation—on the buds, flowers or foliage : others frequent de caying plant-remains especially wood and fungi. A small number are predators and suck the body fluids of aphides and Acari. They are elongate, slender-bodied insects, with short six- to nine-jointed antennae, and asymmetrical piercing mouth-parts. The wings are very narrow and strap-like with greatly reduced venation and long fringes of marginal hairs. The tarsi are one- or two-jointed and the apex of each tarsus is terminated by a minute protrusible bladder or vesicle which enables them to climb almost any surface. The young forms closely resemble the adults in their general form and they ultimately pass into a resting stage or incipient pupa prior to becoming adults. Numerous thrips are wingless and some species consist of both winged and wingless individuals. Partheno genesis is frequent in the order and males are either unknown, or very rare, in several species : in others the eggs are capable of developing parthenogenetically, although males are common.
Thysanoptera are divided into two sub-orders (I) Terebrantia in which the last segment of the abdomen is conical, that of the male being rounded, and the female has a saw-like ovipositor : most of the species feed on living plants. (2) Tubulifera in which the last segment of the abdomen is tubular in both sexes and the female is without a saw-like ovipositor : the species chiefly feed upon dead organic matter, fungi, etc., or form galls in a few cases.
Only a few hundred members of the order have been described, and in most tropical lands thrips, as yet, have been very little studied, but the order is probably world-wide in its range. Aus tralia contains numerous species including some of the largest forms, but no indigenous species have been found in New Zealand.