. A manual for the study of insects. Insects. 52 THE STUDY OF INSECTS. terflies, beetles, bees, and flies, leave the tgg in an entirely different form from that which they assume when they reach maturity. A butterfly begins its active life as a caterpillar. It feeds and grows, and when full grown changes to a chrys- salis. In this stage it has very little resemblance to a cater- pillar. After a time there bursts forth from the chrysalis shell the butterfly, which looks very little like the chrysalis, and still less like the caterpillar from which it came. In a similar way, from the ^"g^ l
. A manual for the study of insects. Insects. 52 THE STUDY OF INSECTS. terflies, beetles, bees, and flies, leave the tgg in an entirely different form from that which they assume when they reach maturity. A butterfly begins its active life as a caterpillar. It feeds and grows, and when full grown changes to a chrys- salis. In this stage it has very little resemblance to a cater- pillar. After a time there bursts forth from the chrysalis shell the butterfly, which looks very little like the chrysalis, and still less like the caterpillar from which it came. In a similar way, from the ^"g^ laid by a fly upon a piece of meat there hatches, not a fly, but a footless, worm-like maggot. This when fully grown changes to a quiescent object corre- sponding to the chrysalis of a butterfly. Later from this ob- ject there escapes a winged fly like that which laid the ^^'g. Those insects, like the butterflies and flesh-flies, which when they emerge from the ^gg bear almost no resemblance in form to the adult insect, are said to undergo a complete met- amorphosis. In other words, the change of form undergone by the insect is a complete one. How Insectsgroiv—^-T\i^ skin of an insect is hard- ened more or less by a horny substance known as chitine (chi^tine). This hardening usually occurs to a much greater extent in adult insects than it does in the young. But in all the skin becomes so firm that it cannot stretch enough to allow for the growth of the insect. The result is, that from time to time an in- sect*s skin becomes too small for it, and must be shed. But before this is done a new skin is formed beneath the old one; then the old skin bursts open, and the insect crawls forth, clothed in a soft skin, which stretches to accommodate the increased size of the animal. Very soon, however, this new skin becomes hardened with chitine, and after a time it in turn must be shed. This shedding of the skin is termed molting^ and the cast skin is some-. FiG. 62rt;.—Exuviae
Size: 1045px × 2392px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectinsects, bookyear1895
