The Natural History of Insects

Introductory Singularity of Transformations-Remarkable Caterpillar of the Swallow-tailed Butterfly-True nature of Chrysalides, and misstatement respecting them-Structure of Chrysalides -Errors of Godart- Golden Chrysalides - Inquiry how the Fluids of Chrysalides are converted into Solids Experiments of Reaumur-Analogy of the inactive State of a Chrysalis with the chewing of the Cud in Animals-State of the Chrysalis when ready to disclose the Butterfly-Extrication of the Fly-Extension of the Antenna and Tongue-Supposed Uses of the Anten ne-Expansion of the Wings-Scales of the Wings.

In the fifth and sixth chapters of our preceding volume, we have detailed the history and proceedings of various kinds of caterpillars; and in the concluding chapter, the seventeenth, we have shown the manœuvres by which the caterpillars of three kinds of butterflies, viz., the white, or cabbage butterfly (Pontia Brassica), the peacock butterfly (Vanessa Io), and the swallow-tailed butterfly (Papilio Machaon), effect their transformations to the inactive state of a chrysalis; the other larvæ which we have described in the two former chapters likewise belong, with the exception of the caddis worms, to various species of moths.

In pursuing the history of these transformations it remains for us to show the manner in which the chrysalis state is thrown off, after which the butterfly appears in all its beauty; but as the proceedings of the butterfly afford but a very insufficient idea of VOL. II.-B

the various kinds of transformations undergone either by the moths or insects of other orders, we shall enter into the subject at further detail, feeling convinced that it is impossible for us to lay before our readers any subject connected with these little animals which so fully coincides with the title of our work-" The Natural History of Insects."

The manner in which Messrs. Kirby and Spence introduce this subject is so appropriate, that we cannot resist the temptation to quote it, as being admirably adapted to rouse the attention of the student to the metamorphoses of the insect world:-" Were a naturalist to announce to the world the discovery of an animal which for the first five years of its life existed in the form of a serpent, which then penetrating into the earth, and weaving a shroud of pure silk of the finest texture, contracted itself within this covering into a body without external mouth or limbs, and resembling more than any thing else an Egyptian mummy; and which, lastly, after remaining in this state, without food and without motion, for three years longer, should, at the end of that period, burst its silken cerements, struggle through its earthy covering, and start into day a winged birdwhat think you would be the sensation excited by this strange piece of intelligence? After the first doubts of its truth were dispelled, what astonishment would succeed!-among the learned what surmises! what investigations!-among the vulgar what eager curiosity! what amazement !”

Swammerdam, indeed, justly observes-"This history is so amazing in all its circumstances, that it might very well pass for a romance were it not built upon the most firm foundations of truth;" and the illustrious Goethe, whose knowledge of mankind was only equalled by his love of nature, says of these changes, “I would call these transmutations wonderful, if the wonderful in nature were not that which occurs every moment."

We will now proceed more minutely to detail the manner in which these transformations are effected, especially the circumstances connected with the escape of the butterfly from the chrysalis, continuing to take as examples the three species of butterflies noticed above, and whose caterpillars we have figured in our former volume. There are several peculiarities, however, connected with the caterpillar of the swallow-tailed butterfly, which will be considered interesting.

Until recently this butterfly, which is by far the most remarkable of the British species, was of very rare occurrence in England; but it has within these few years been found plentifully in the fens of Cambridgeshire and Huntingdonshire. The caterpillar of this fine butterfly is of a green colour, with velvety black rings, which are alternately spotted with red; it feeds upon various umbelliferous plants, especially the fennel and carrot, preferring the flowers, and is remarkable for having the back of the neck armed with a red-coloured instrument composed of two fleshy horns, branching from a common stem, and shaped somewhat like the letter Y; this organ appears to be similar in some respects to the horns of snails, and is capable of similar movements, being completely retractile. It appears from the observations of Reaumur that it is only when the caterpillar is disturbed that it throws out this instrument, sometimes to its whole extent, at others with the horns only protruded thus Y, and occasionally with them unequally extended thus y; and, as it secretes an acrid liquor which emits an unpleasant smell, particularly when the animal is irritated, it is probably an organ of defence, to protect it from the attacks of the ichneumon flies. Reaumur mentions the remarkable circumstance that the caterpillar, when spinning the silken cord by which it is to be supported on assuming the chrysalis state, invariably affixes it across its body at the junction of the

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The Natural History of Insects, Volume 2