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(horntails), a family of symphytic hymenopterous insects having a cylindrical abdomen. The females have a stout, sometimes very long, ovipositor (hence the common name). Adult horntails do not feed.
Of the approximately 200 species of horntails, 20 are found in the USSR. The insects develop in wood, mainly the wood of coniferous trees. The female pierces the bark with the ovipositor and deposits the eggs, one to three at a time, in a row along the trunk. Spores of wood-destroying fungi, located in a pouch on the female’s abdomen, simultaneously enter the wound in the bark. The cylindrical, white or yellowish larva, which has three pairs of thoracic legs and a spine at the end of the abdomen, gnaws a passage in the wood and feeds on the wood-destroying fungi, which line the passage. Pupation occurs in the wood. The entire developmental cycle lasts one or two years.
All horntails are pests of lumber. Many species attack externally healthy trees, selecting trunks with mechanical injuries. In the USSR the greatest harm is done by Tremex fuscicornis, which infests hardwood, and by Sirex gigas, Paururus juvencus, Paururus ermak, and Xeris spectrum, which are pests of conifers.
G. M. DLUSSKII