Whittock, Nathaniel: The Art Of Drawing And Colouring, From Nature, Birds, Beasts, Fishes, And Insects: With Plain And Coloured Drawings, From Original Paintings By Morland, Vernet, Howet, Le Cave, &c. (London, 1830)

each side; a hole for every ring, except the second, third, and last.
These oval openings, or mouths, are each accompanied with lungs, a
fact which has been fully ascertained by anatomists. That these vessels
serve to convey the air, there can be no doubt; Malpighi proved
this by stopping up these mouths with oil, when the animal instantly
became convulsed and died ; on silling up the stigmata on one side
only, the animal underwent a partial convulsion, but recovered in a
short time.
The skin of the caterpillar is changed nine or ten times, and though
the operation is attended with considerable labour, it only occupies
the space of a minute ; and the animal seems always to acquire new
vigour and beauty with its new covering. Having continued for
several days feeding, and at intervals casting its skin, it begins to
show symptoms of its approaching change into an aurelia; by attach-
ing itself to the branch of the tree, and ceasing to feed upon leaves, it
prepares, by fasting, to undergo its transformation. Those cater-
pillars that are capable of spinning proceed to weave themselves a
cone or web, and under this covering the animal labours incessantly
till it has cast off its skin as a caterpillar, and becomes an aurelia;
and, seemingly quite exhausted with its efforts to free itself from the
caterpillar state, it lies for some hours motionless. The form of the
future butterssy may be distinguished, but its colour is green; after
being exposed to the air for some hours its body hardens, and the
external covering becomes encrusted with a glossy varnish, which
gives it, in some cases, a golden hue, which has caused some authors