In this class of insects we find both, friends and foes. The former assist us by their voracious appetites, that can only be satisfied with gourmandizing upon other insects, particularly the juicy bodies of their larvæ. The latter embrace some of our most troublesome pests, especially as they consume vegetable matters, in the perfect as well as in the larval condition, and in both stages are exceedingly voracious. Moreover, they generally commit their depredations under cover, or at night. Some live in the soil and consume the roots of our plants, and others mine their way into the solid wood of the stems of our finest trees; while some only affect the twigs and smaller branches, and others devour the foliage, flowers, and fruits. A few of the most familiar and troublesome of these will now be introduced; and allusion will also be made to some of those which befriend us by their destruction of other insects. =Saperda bivittata.= (_Say._)--The Apple Tree Borer.--This is a nocturnal insect, which has been found very destructive to our orchards. The female deposits one egg in a place, generally low down on the stem of the tree; this hatches, and enters the tissues of the bark, where it feeds for a time, a footless grub. As it grows, it burrows deeper, and upward, until it reaches the sap wood, upon which it feeds. When half grown, it burrows still deeper, and upwards into the heart of the tree, and then outward through the sap wood to the bark, but retires again toward the centre, as to a place of safety, to undergo its transformation, after packing the hole with shreds of wood and with its castings to make its retreat secure. In the spring, the perfect insect opens its way outward, and emerges to the light of day. REMEDY.--Observe the bark of young trees very closely during the summer, to discover the castings that are ejected; notice the discolored or depressed portions of bark, and cut into them to find and destroy the worm--if it has penetrated the solid wood, pursue it with a piece of stout but flexible wire. PREVENTIVES.--Alkaline washes have been highly recommended, as a means of driving away the mother beetle; soft soap may be used, and a portion of soft or hard soap, placed in the forks of the branches, will dissolve with the rains, and wash down on the bark. These applications, to be efficacious, should be made in May or June. In August, the bark should be examined, and when the worms are cut out, the soap suds may be injected with advantage, especially if the larvæ have not been reached. Birds should be encouraged, particularly the Picæ tribe, which destroy many grubs of the wood-boring insects.