But a change, far more important than mere skin-shifting, follows close upon the animal's caterpillar-maturity, complete as soon as it ceases to grow.
The form and habits of a worm are to be exchanged for the glories and pleasures of winged life; but this can only be done at the price of passing through an intermediate state; one neither of eating, nor of flying, but motionless, helpless and death-like. { 12}
This is called the CHRYSALIS _or_ PUPA _state_.
_Pupa_ is a Latin word, signifying a creature swathed, or tied up; and is applied to this stage of all insects, because all, or some, of their parts are then bound up, as if swathed.
The term _Chrysalis_ is applicable to butterflies only, and, strictly, only to a few of these--_Chrysalis_[1] being derived from the Greek [Greek: chrusos] (_chrysos_), _gold_--in allusion to the splendid gilding of the surface in certain species, such as the _Vanessas_, Fritillaries, and some others.
In the older works on entomology we frequently meet with the term _Aurelia_ applied to this state, and having the same meaning as chrysalis, but derived from the Latin word _Aurum_, gold.
Here the reader is again referred to Plate I. for a series of the principal forms assumed by the chrysalides of our native butterflies, and as these for the most part represent the next stage of the caterpillars previously figured, an opportunity is afforded of tracing the insect's form through its three great changes; the whole of the butterflies in their perfect state being given in their proper places in the body of the work.
{ 13} The complicated and curious processes by which various caterpillars assume the chrysalis form, and suspend themselves securely in their proper attitudes, have been most accurately and laboriously chronicled by the French naturalist, Réaumur; but his memoirs on the subject, which have been frequently quoted into the larger entomological works, are too long for insertion here in full, and any considerable abbreviation would fail to convey a clear idea of the process, on account of the intricacy of the operations described. So I can only here allude to the difficult problems that the creature has to solve, referring the reader to the above-mentioned works for a detailed description of the manner of doing so; or, better still, I would recommend the country resident to witness all this with his own eyes. By keeping a number of the caterpillars of our common butterflies, feeding them up, and attentively watching them when full-grown, he will now and then detect one in the transformation act, and have an opportunity of wondering at the curious manoeuvres of the animal, as it triumphs over seeming impossibilities.