CHAPTER LXVI.
1292. Why does the caterpillar become torpid when passing into the state of the chrysalis?
Because in all probability, where the difference between the first and the ultimate form is considerable, the organs of the insect having to undergo great changes, it would suffer considerable pain. Torpor comes upon the insect, it is thrown into a state similar to that of a person who has inhaled chloroform; and after what has, in all probability, proved a pleasant dream, the insect awakes to find itself changed and beautified.
1293. Why are the pupæ of grasshoppers and other insects, when about to undergo transformation, still active and sensitive?
Because, as there is but a slight difference between the form which they have in the pupa state, and that which they ultimately assume, they do not require the state of torpidity to save them from pain, nor to arrest their movements while their organs are being changed. With them the outer skin is thrown off, and they are then perfect insects.
1294. Why do caterpillars, when about to pass through the chrysalis state, attach themselves to the leaves of plants, &c.?
Because they know instinctively that for a time they will be unable to controul their own movements, and to avoid danger. They therefore choose secure and dry places, underneath leaves, or in the crevices of old and dry walls, and there they firmly attach themselves, to await the time of their liberation.
1295. Why do insects attach their eggs, to leaves &c.?
Because, as the eggs have to be preserved during the winter, the insect attaches them to some surface which will be a protection to them. Generally speaking, the eggs are attached to the permanent stems of plants, and not to those leafy portions which are liable to fall and decay. The spider weaves a silken bag in which it deposits its eggs, and then it hangs the bag in a sheltered situation. Nature keeps her butterflies, moths, and caterpillars, locked up during the winter, in their egg-state; and we have to admire the various devices to which, if we may so speak, the same nature has resorted for the security of the egg. Many insects enclose their eggs in a silken web; others cover them with a coat of hair, torn from their own bodies; some glue them together; and others, like the moth of the silk-worm, glue them to the leaves upon which they are deposited, that they may not be shaken off by the wind, or washed away by rain; some again make incisions into leaves, and hide an egg in each incision; whilst some envelope their eggs with a soft substance, which forms the first aliment of the young animal; and some again make a hole in the earth, and, having stored it with a quantity of proper food, deposit their eggs in it.