Weaker grows the caterpillar as the gnawing worms within grow stronger and nearer maturity. Sometimes he dies a caterpillar, sometimes he has strength left to take the chrysalis shape, but out of this he _never_ comes a butterfly--the consuming grubs now finish vitals and all, turn to pupæ in his empty skin, and come out soon, black flies like their parent.
But, supposing that it has escaped this great danger, we now see the creature in its completest form, as the
The first term, _Imago_, is a Latin one, merely signifying an image, or distinct unveiled form; as distinguished from the previous _larva_, or masked state, and the _pupa_, or swathed and enveloped state. The word _imago_ then, in works on entomology, always means the { 20} perfect and last stage of insect life, and is applied to all insects with wings--for it must be borne in mind that no insect is ever winged till it reaches the last stage of its existence.
If the progressive development of these lovely beings is so marvellous, no less so is their structure when perfected, and of this some general description must now be attempted.
In contemplating a butterfly, one feels that the mind is first engaged by that ample spread, and exquisite painting of the wings that form the creature's glory; let therefore these remarkable organs have our first attention.
Wherein do these wings chiefly differ from all other insect wings? Certainly in being covered thickly with a variously coloured powdery material, easily removed by handling. This apparent dust is composed, in reality, of a vast number of regularly and beautifully formed _scales_--feathers they are sometimes called, but they are more comparable to fish scales than to any other kind of natural covering. The general term _Lepidoptera_, applied to _all_ butterflies and moths, is derived from these _scaly-wings_; _Lepis_[2] being the Greek for a _scale_, and _ptera_ meaning _wings_ in the same language.
The use of a tolerably powerful pocket lens will afford _some_ insight into the exquisite mode of painting
{ 21} employed in these matchless pieces of decoration; but the possessor of a regular microscope may, by applying it to some of our commonest butterflies, open for himself a world of beauty, and feast his eyes on a combination of refined sculpture with splendour of colouring; now melting in softest harmony, then relieved by boldest contrast--a spectacle, the first sight of which seldom fails to call forth expressions of wonderment and warm delight; and, truly, little to be envied is the mind untouched by such utter beauty as here displayed.