The first creature that we will notice is that caterpillar which is so abundantly found at several seasons of the spring and summer, and, from the long hairy skin in which it is enveloped, goes by the popular name of the “Woolly Bear!” A figure of this creature may be seen in plate B, fig. 5 _a_. This creature is the larva of the common Tiger-moth, which is represented on the same plate, fig. 5.
It will be necessary to pause here a little, before proceeding to the description and histories of the various insects, because in the course of description certain terms must be used, which must be explained in order to make the description intelligible.
In the first place, let it be laid down as a definite rule, that
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.