. Natural history. Zoology. Sa w-flies and wood- wasps. 575 TenthredinidcE, but ig most frequently nine, especially in the more typical sub-families, in which the joints are long, cylindrical, and well-marked. In one sub-family, however, the short, thick Antennsa of Saw antennae are composed of only three well-separated joints ; Flies. the scape, a short joint, and a long terminal one composed of several fused together. Sometimes this third joint is bifid, each antenna being thus double nearly to the base. Our fruit-trees often suffer severely from the attacks of the larvfe of various saw-flie
. Natural history. Zoology. Sa w-flies and wood- wasps. 575 TenthredinidcE, but ig most frequently nine, especially in the more typical sub-families, in which the joints are long, cylindrical, and well-marked. In one sub-family, however, the short, thick Antennsa of Saw antennae are composed of only three well-separated joints ; Flies. the scape, a short joint, and a long terminal one composed of several fused together. Sometimes this third joint is bifid, each antenna being thus double nearly to the base. Our fruit-trees often suffer severely from the attacks of the larvfe of various saw-flies. Those best known to ordinary observers are probably the small greenish or yellowish black-dotted larvre which frequently strip our gooseberry and currant bushes of all their leaves, Saw-Flies and which develop into small black and yellow four-winged injurious to flies about half-an-inch in expanse, belonging to various species ^'''^i* trees, of thegreat genus Nematu (Panzer.). But these bushes are li- able to the attacks of the larvfe of saw-flies belonging to other sub-families than iheNematince., and also by the larvse of various Lepidoptera and other insects. The Siricidce, or wood-wasps, burrow in the larva state in timber, with which they are frequently imported into this country. The commonest and most conspicuous species is Sirex gigas (Linn.),avery Wood-Wasps formidable - looking in- (Siricidct). sect, the large females of which sometimes measure nearly two inches across the wings, though many, specimens are much smaller ; for wood- feeding insects, as a rule, vary very much, both in size, and in the length of time which they require to reach matu- rity. It is black and yellow, and the Fig. gigas. Nat. female has a stout ovipositor projecting behmd the body for about one-third of its length. The abdomen of the male, on the other hand, terminates in a rectangle. Tliese insects will soraetimesemergefrom planks of deal or pine, which have been buil
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