. The transformations (or metamorphoses) of insects. Insects; Insects; Myriapoda; Arachnida; Crustacea. J8 TRANSFORMATIONS OF INSECTS, These pieces are intimately united, and have been called pre- scutum, scutum, scutellum, and postscutellum. The first is always very rudimentary, and is a little lamina placed vertically to the edge of the segment, and remains in a membranous condition in a great, number of insects. The second, which supports the wings^ is larger. The third, often very small, is placed between the wing cases of most beetles. The last piece, often reduced to a mere ridge behind
. The transformations (or metamorphoses) of insects. Insects; Insects; Myriapoda; Arachnida; Crustacea. J8 TRANSFORMATIONS OF INSECTS, These pieces are intimately united, and have been called pre- scutum, scutum, scutellum, and postscutellum. The first is always very rudimentary, and is a little lamina placed vertically to the edge of the segment, and remains in a membranous condition in a great, number of insects. The second, which supports the wings^ is larger. The third, often very small, is placed between the wing cases of most beetles. The last piece, often reduced to a mere ridge behind the third piece, assists in the formation of the joints of the wings. The thorax sustains the locomotive organs. These are the true legs which belong to the lower arches of the segments, and the wings which are connected to the upper arches. The true legs often exist in the young insect, but are then very small and scale-like, and they do not attain a considerable size until adult age is reached. They are from the first in three. LARVA OF THE SILKWORM. TRUE AND MEMBRANOUS LEGS. pairs. Those attached to the prothorax are the anterior legs; those of the mesothorax are the intermediate; and the posterior are in relation with the metathorax. The legs upon the segments of the abdomen are, as has already been noticed, not persistent; they exist in caterpillars especially, and are really membranous feet, being provided with hairs, spines, and hooks to hold on with, but they are lost during the metamor- phosis into the chrysalis condition. The front or true legs are the curious jointed structures so finely hairy and so well provided with suckers, claws, and brushes of hair, and are mainly developed during the period of rest which characterises the chrysalis state. The distinction between the true legs and the sucker-like feet of the caterpillar is very observable in the engraving of the silkworm larva; the true or scale-like legs are in front, and are not adhering to anything, but the
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Keywords: ., bookcentury1800, bookdecade1870, booksubjec, booksubjectcrustacea
