and (heaths of the anterior limbs, and in general all that is vifible-
o f the caterpillar.
The new organs were under the old ones as in a fheath, fo
that the caterpillar effects the changes by withdrawing itfelf from
the old fkin, when it finds itfelf lodged in too narrow a compafs.
But to effect this change, to pufh off the old covering, and bring
forwards the new, is a work of labour and time. Thofe caterpillars
who live in fociety, and have a kind o f nefl or habitation,
retire there to change their fkin, fixing the hooks of the feet,
during the operation, firmly in the web o f their nefl. Some o f -
the foJitary fpeeies fpin at this time a (lender web, to which they
affix themfelves. A day or two before the critical moment approaches,
the infeft ■ ceafes to eat, and Iofes it’s ufual aftivity;
in proportion as the time o f change approaches, the colour of the-
caterpillar becomes more feeble, the fkin hardens and withers,
and is foon incapable of receiving thofe juices by which it
was heretofore nourifhed and fupported. The infeft; may now
be feen, at diftant intervals, to elevate it’s back, and ftretch itfelf
to it’s utmoft extent; fometimes to lift up the head, move it a.
little from fide to fide, and then let it fall again ; near the change,
the fecond and third rings are feen to fwell confiderably; by thefe
internal efforts the old parts are flretched and diftended as much
as poffible, an operation which is attended with much difficulty,
as the new parts are all weak and tender. However, by repeated
exertions, all the veffels which conveyed the nourifhment to the
exterior fkin are difengaged, and ceafe to aft, and a flit is made
on the back, generally beginning at the fecond or third ring ; the
new fkin may now be juft perceived, being diftinguifhed by the
frefhnefs and bnghtnefs o f it’s colour; the caterpillar then prefles.
the
the body like a wedge into this; flit, by which means it is foon
opened from the firft down to the fourth ring ; this renders it large
enough for the infeft: to pafs through, which it foon effefts in a
very curious manner. The caterpillar generally fafts a whole
day after each moulting, for it is neceftary-that the parts fhould
acquire a certain degree o f confiftency, before it can live and aft
in it’s ufual manner; many alfo periffi under the operation.
The infeft always appears much larger after it has quitted the
exuvia ; the body had grown under the old fkin, till it was become
too large for it: now as the growth was gradual, and the
parts foft, the fkin preffed them together, fo that they lay in a
(mail fpace; but as foon .as the fkin is caft off, they are as it
were liberated from their bonds, and diftend themfelves confiderably.
Some caterpillars, in changing their fkin, from fmooth
become covered with fine hair ; while others, that were covered
with this fine hair, have the laft fkin fmooth.*
O f t h e P u p a .
Before we defcribe the change of the larva into the pupa (late,
it will be neceftary to give the reader? an account o f thofe names
by which naturalifts diftinguifh the different.appearances o f infefts
in the pupa ftate.
It is called coarcta ta, when it is ftraitened or confined to-
a cafe of a globular form, which has no refemblance to the infeft
it contains.
It
* Valmont de Bomare Difiionnaire Univerfel d’ Hifloire Naturelle, rol.. ii.
2d edit., ramp. ,p- 394-