OMMONLY KNOWN as thrips, the

_ order Thysanoptera contains 8

families and 5,000 species. They are small, slender insects usually with two pairs of narrow, hair-fringed wings. The head bears short antennae, conspicuous compound eyes, and distinctive sucking mouthparts, which include a pair of mandibles in which one is small and the other is needlelike. There is a sticky, inflatable structure between the tarsal claws that aids grip on smooth surfaces.

Thrips are closely related to bugs but are unusual in that they undergo neither complete nor incomplete metamorphosis. As in members of the order I Iymenoptera (see pp. 178-206), fertilized eggs produce females and unfertilized eggs produce males. There are also one or more pupalike stages after the two nymphal stages. The females of some species have a sawlike ovipositor and lay their eggs inside plant tissue, while others lack an ovipositor and lay their eggs in cracks and crevices or on the surface of host plants.

Thrips may be herbivorous or predacious. A few species show simple forms of social behavior, and in some there are soldiers who defend their colony. Many thrips are plant pests -especially of cereal crops.



No. of species 250

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