Of the Change of Caterpillars into the Chrysalis State.
When a Caterpillar has fed its appointed Time, and is come to full Maturity, it undergoes a Change, and becomes a Body of a different Form, incrusted with a Shell, and usually called a Chrysalis or Aurelia; the Shell of which is formed underneath the Skin of the Caterpillar, which Skin comes off as soon as the Aurelia becomes perfect.
Of the Chrysalis or Aurelia.
During its Continuance in the Chrysalis State, it seems to have no Sense but Feeling; and some of them have even that in a very low Degree, for they may be touched pretty roughly without moving.
The Chrysalides or Aureliæ of the Butterfly-Kind are all very beautiful; some of them look as if they were studded with Gold; some are striped, others spotted, and others mottled with all the various Colours of the Rainbow. But those of the Moth-Kind are not so; differing very little from one another, either in Shape or Colour, except the Magpye, and some few besides.
How the Aurelia or Chrysalis is secured.
Nothing in Nature is perhaps more deserving Notice, than the many different Methods whereby Caterpillars conceal and secure themselves whilst in this helpless and unactive Condition.
Some of them spin a large Case of Silk in Form of an Egg, wherein the Chrysalis lies concealed, till the Time comes for the Fly to make its Appearance, which it does by piercing through this Case.
Of such Cases there are several Sorts, different in Form and Colour:
Some are long, and drawn out to a Point at each End; others are more round.