The winter draws near, and sends its foretokening cold breathings to warn every creature, vegetable and animal, that the dark season is arriving, when food is no longer to be obtained. What is to become of the larva? Can it endure the penetrating tooth of frost, or the overwhelming shower of rain? Or can it endure to be from week to week, from month to month, without a mouthful of food? From the facts already stated with reference to the age of larva, it is very certain that many larvæ have to bear these trials; and some, not merely during one, but during several winters. We must, therefore, inquire how they have been defended, or strengthened, so as to enable them so to do.
The alteration in the coats of animals during winter, or rather, just previous to it, and the fact that animals destined to inhabit the arctic regions are enveloped in coats of the shaggiest hair, are well known to every person. There can be no doubt, that in many instances in the insect world, where a larva has to be exposed to the frosts of winter, the same provision of a hairy covering, which has been given to them by the Creator, is intended to meet the same end, and to preserve their soft and tender bodies from the destructive influence of extreme cold. The following striking observation of a talented entomologist, who has not thought it beneath him to write a most interesting book only on the family of ants (M. Huber), shows very clearly that such is, in fact, the intention of providing the larva with a covering of this kind. He noticed that the larvæ of some species of ants destined to pass through the winter, were furnished with this kind of warm clothing, while those which were not so destined had smooth coats, that is, even in the same species: thus proving to us, beyond a doubt, that as the winter approached, the warm coat was put on by the larvæ. The engraving on the last page represents some extraordinary specimens of hairiness in caterpillars from Brazil, now in the British Museum.
A large number of larvæ become torpid during winter--they are not dead--they are not sensibly alive--they are plunged in that long half-death which affects not only them but also many large animals, who retire in winter, lie down to sleep for weeks, and awake to find the cold departing, and the spring-time nigh at hand. But the frost sometimes proves too severe for them, and the poor insects become sometimes congealed into solid lumps of ice! Alas! we shall exclaim, then there is an end to their life when that takes place; and, undoubtedly, the severity of such a degree of cold destroys large numbers; yet, strange to say, some larvæ actually revive, even after they have been thus frozen into hard inanimate lumps. One observer states that he has found them in this condition; and so entirely congealed, that they chinked like small stones when dropped into a glass tumbler! yet they revived after careful management. In an experiment made during Sir John Ross's voyage to the arctic regions, upon the larvæ of a moth, they were four successive times exposed to the intense cold of 40° below zero, and four times they revived again on being brought into the warm atmosphere of the cabin. Experiments have also been made by other persons with a like result. It may, therefore, be considered certain that some larvæ will bear to be frozen into solid masses, so that they will snap asunder like an icicle, and yet return to life again; and even go through all their stages of development, into the perfect insect. How remarkable a fact this is, when we remember the deadly effect of frost upon man and the higher animals!