. A treatise on some of the insects injurious to vegetation . Insect pests. more, till nothing is left but the dry outer convex skin, and the insect perishes on the spot. Sometimes the insect's body is not large enough to cover all her eggs, in which case she beds them in a considerable quantity of the down that issues from the under or hinder part of her body (Fig. 95). There are several broods of some species in the year; of the bark-louse of the apple-tree at least two are produced in one season. It is probable that the insects of the second or last brood pair in the au- tumn, after which t
. A treatise on some of the insects injurious to vegetation . Insect pests. more, till nothing is left but the dry outer convex skin, and the insect perishes on the spot. Sometimes the insect's body is not large enough to cover all her eggs, in which case she beds them in a considerable quantity of the down that issues from the under or hinder part of her body (Fig. 95). There are several broods of some species in the year; of the bark-louse of the apple-tree at least two are produced in one season. It is probable that the insects of the second or last brood pair in the au- tumn, after which the males die, but the females survive the winter, and lay their eggs in the following spring. Young apple-trees, and the extremities of the limbs of older trees, are very much subject to the attacks of a small species of bark-louse. The limbs and smooth parts of the trunks are sometimes completely covered with these insects, and present a very singularly wrinkled and rough appearance from the bodies which are crowded closely together. In the winter these insects are torpid, and ap- parently dead. They measure about one tenth of an inch in length, are of an oblong oval shape, gradually decreasing to a point at one end, and are of a brownish color very near to that of the bark of the tree. These insects resemble in sliape one which was described by Reaumur* in 1738, who found it on the elm in France, and Greoffroy named the insect Coc- cus arborum linearis, while Gmelin called it conchiformis (Fig. 96). This, or one much like it, is very abundant upon apple-trees in England, as we learn from Dr. Shawf and * Memoires, Vol. IV. p. 69, plate B, figs. 5, 6, 7. I General Zoology, Vol. VI. Part I. p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Harris, Thaddeus William, 1795-1856; Flint, Charles Louis,
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Keywords: ., bookcentury1800, bookdecade1860, bookpubl, booksubjectinsectpests
