INSECTS NEVER GROW.
Many people fancy that a little fly is only little because it is young, and that it will grow up in process of time to be as big as a blue-bottle. Now this idea is entirely wrong; for when an insect has once attained to its winged state, it grows no more. All the growing, and most part of the eating, is done in its previous states of life; and, indeed, there are many insects, such as the silkworm-moth, which do not eat at all from the time that they assume the chrysalis state to the time when they die.
It is a universal rule in nature, that nothing comes to its perfection at once, but has to pass through a series of changes, which if carefully examined can mostly be reduced to three in number. Sometimes these changes glide imperceptibly into each other, but mostly each stage of progress is marked clearly and distinctly. Such is the case with the insect of which we are now considering; and when we have examined the development of the Tiger-moth through its phases of existence, we have the key to the remainder of the insects.
After an insect has left the egg, and entered upon the world as an individual being, it has to pass through three stages, which are called larva, pupa, and imago.
The word “larva,” in Latin, signifies “a mask,” and this word is used because the insect is at that time “masked,” so to speak, under a covering quite different from that which it will finally assume. In the present instance, the Tiger-moth is so effectually masked under the Woolly Bear, that no one who was ignorant of the fact would imagine two creatures so dissimilar to have any connection with each other.
Throughout this work the word “larva” will be always understood to signify the first of the three states of insect life, whether it be a “caterpillar,” a “grub,” or a “worm”.
In its next stage the insect becomes a “pupa,” which word means a “mummy,” or a body wrapped in swaddling clothes. This name is employed because in very many insects the pupa is quite still, is shut up without the power of escape, and looks altogether much like a mummy, wrapped round in folds of cloth. In the moths and butterflies the insect in this stage is called a “chrysalis,” or “aurelia,” both words having the same import, the first Greek and the other Latin, both derived from a word meaning “gold”. Several butterflies—that of the common cabbage butterfly, for example—take a beautiful golden tinge on their pupal garments, and from these individual instances the golden title has been universally bestowed.
The last, and perfected state, is called the “imago,” or image, because now each individual is an image and representative of the entire species.
The Woolly Bear, then, is the larva of the Tiger-moth; and if any inquiring reader would like to keep the creature, and watch it through its stages, he will find it an interesting occupation. There is less difficulty than with most insects, for the creature is very hardy, and the plant on which it mostly feeds is exceedingly common.