OF THE PUPA STATE. 71 
dition. ‘The caterpillar has two spirally convoluted 
tubes filled with a silky gum, but in the butterfly 
both these have nearly disappeared; and equally 
wonderful changes have taken place in the struc- 
ture and dispositions of the nerves and other organic 
processes. 
Such are the extraordinary metamorphoses to 
which this animal is subject. It will be observed, 
that the change from the one form to the other was 
not direct, and that a distinct, and not less singular 
state intervened. After casting its skin several times, 
and even parting with its jaws, and at length, pro- 
gressing in bulk, and attaining its full growth, the 
caterpillar attaches itself to a leaf by a silken fila- 
ment. In this condition its body becomes much 
contracted ; its skin splits once more, and discloses 
a uniform mass, without exterior eyes, mouth, or 
limbs, and exhibiting no appearance of life except 
when touched, in which case it gives indications of 
existence by a slight motion. In this deathlike 
casement, in a state of torpor, it remains for months 
without food. The casement at length bursts, and 
although not longer than an inch, and in dia- 
meter a quarter of an inch, a butterfly springs into 
existence of dimensions extraordinary, covering a 
surface of nearly four inches square. 
Butterflies and moths, while in the pupa state, 
are enclosed in a membranous skin, with their legs, 
entenne, and wings, closely folded over their breast 
