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Thysanoptera (thrips; class Insecta, subclass Pterygota) Order of slender, minute (mostly 0.5–2 mm long), pale to blackish insects which have short, six-nine-segmented antennae, short legs, and asymmetrical, sucking mouth-parts which form a conical beak on the ventral surface of the basal head area. Wings, when present, are in two pairs, with very reduced venation and long fringe hairs. The two suborders, Terebrantia and Tubulifera, differ in the shape of the abdomen and development of the ovipositor. Most thysanopterans are herbivores and many are pests of cereals and fruit trees (e.g. onion thrips, grain thrips, pea thrips, and greenhouse thrips). A few act as vectors of plant diseases. Some thrips are predacious on other small arthropods, and many feed on fungal spores. There are about 4500 species, distributed world-wide.