WOOD-BORING BEETLES, beetles which lay their eggs in or upon wood, into which the larva begin to bore immediately after hatching and from which they derive their sole sustenance. Living upon this innutritious sub stance their growth is generally slow, and by the end of the several years spent in the larval condition they have often excavated extensive galleries winch increase in diameter as the larva The larva of many beetles feed upon or decaying wood only, and many of these may be considered useful to man, as they assist in reducing stumps and fallen limbs to a condition of vegetable mold. Others con fine their attacks to the bark and are seldom serious pests. Many species bore into sound wood in the standing growing tree, in the dressed lumber, or even in the finished house or article of furniture. Such often conunit in calculable damage. The families Cermetryciskr and Dooprostides are notorious as comprising species almost exclusively of wood-boring hab its, and those whose larva do not excavate wood burrow into roots or soft plant tissues. The Ceranotrycide (q.v.), or longicorn beetles, in dude one of our largest beetles, the broad necked prionus (Priming laiticolks), which reaches a length of nearly two inches and is unusually robust for the family; it is of a deep brown-black color, and the jaws are exceed ingly stout. The great white larva, are two or three inches long and bore into the roots of forest and orchard trees and blackberry plants. The latter are quickly killed and even large trees will succumb if the borers are abundant. They live three years. The apple-tree borer (Saperda tandida) in the beetle state is brown with a conspicuous white stripe running the entire length of the body on each side above. It flies mostly at night during the early summer mouths and lays its eggs on the tracks of apple, quince and pear trees near the ground. The larva is cylindrical and very strongly annu lated and when fully grown is an inch long. It lives three years, the first one being spent in the sap-wood, the others in the interior of the trunk. Its attacks are frequently fatal and the only effecUve measures are preventives. A strip of tin or wire gauge nailed to the tree trunk from the ground to a height of two feet will prevent most of the females from de positing their eggs. Another exceedingly seri uns pest is the locust-tree borer (CyIlene rob Doer) which has habits similar to the last and which often riddles the trunks of locust-trees with its burrows, killing them in a few years.
The beetles are very pretty, being dark vehety brown. with angtilated cross-lines of yellow. They abound during the early autnmn and feed upon the pollen of the goldenrods. Numerous closely related species attack other hardwood trees A peculiar habit is possessed by the twrg-girdler (Ortridrres ringulators) which in order to provide its larvae with the dead wood upon which then feed cuts a deep circular trench a mood the Nis-, of hickory and other tries below the point at which its 1.0.:4. haer been The twig dies, tails to the round and the larvr completes its span ut life in security The specie, of truerc.torla (rt s ) greatly in appearance from the kietgicorns; hut have similar habits. The larva. arc distinguish able by the greatly expanded prothoracic ring immediately following, the bead, which is very small and retractile. They are always footless_ Although the huprestids nearly equal the longi corns in number of species, and exceed these in variety of forms those in our fauna are smaller and because of their plainer colors, much less conspicuous. Many of the tropical species, however, are of great size and brilliant colors and some of their larva which may ex ceed four inches in length, are eaten. A species very injurious to pear orchards is the stmutte borer (Agrilus urinates) whose extensive winding galleries in the cambium layer often almost completely sever the bark from the wood and kill the tree. The beetle is about half an inch long and both it and the larva are slender. Blackberry canes are often infested by another species (Agrilus refit-nits), the lar va of which excavate irregular passages and cause the formation of gall-fike enlargements_ The species of Chrysobothris form excavations beneath the bark and in the sapwood of ven ous forest trees, and one species (C. fernorata) is an orchard pest and another (C. hanini) injures the white pine.
The true bark-borers mostly belong to a family, the Scolytidtx. closely related to the weevils (q.v.). They form most elaborate bur rows on the inner-surface of the hark, con sisting of numerous galleries radiating in all directions from a central chamber. See MUM