SAW-FLY, Tenth•edo, a Linmean genus of insects of the order hymenoptera, now divided into many genera; and constituting a family of which the species are very nume rous. They derive the name saw-fly from the ovipositor of the females, which is scaly, serrated, pointed, and inclosed in a sheath. of two concave plates. By means of this instrument, fhe female perforates the stalks 'or other parts of plants, laying an egg in each hole. The hole soon becomes filled with a frothy liquid, and sometimes a gall like swelling is formed, within which the larva resides. The laryx of many raw flies, however, live in no such nests,' but feed on foliage, like caterpillars, which they very much resemble. One of the most common species of gooseberry "caterpillar" is the larva of a saw-fly (nematus ribesil). Saw-flies have the abdomen cylindrical, and so united to the thorax that the distinction is not easily perceived. They vary much in the antennae. Both pairs of wings are divided by nervures'into numerous cells. Among
the more notable species is the CORN SAW-FLY (cephus pygmmus), which, in its perfect state, abounds on umbelliferous flowers, n shining black insect, marked with yellow, the abdomen elongated. The larva consumes the inside of the straw of corn, and descend ing to the base of the straw, cuts it down level with the ground.—Another important species is the TURNIP SAW-FLY (athaliq epinarum), reddish, spotted with black; the larva nearly black, and known by the names of Black Jack and Nigger. The turnip saw-fly is sometimes very troublesome and destructive for a year or two, and then almost com pletely disappears for a number of years. It has sometimes been very destructive to the turnip-crops of Britain.—The saw-fly of the pine (lophyrns pini) is a common British spe cies, and sometimes, though not very often, strips pine and fir trees of their leaves.