26. The BOOK 
the Caterpillar ceafes to eat, and its fkin on 
each fide of the thorax, near under the head, 
is then ob{erved to be’ more and more elevated 
by the increafing and {welling limbs, and 
fhews the appearance of two pair of prominent 
tubercles. | 
That it may be known at what time the 
changes in the Caterpillar comes on, exactly and 
regularly, I thall proceed to explain the fourth 
figure, N°.1V. This defign exhibits the Cater- 
pillar fwoln, @ J, all about the fecond and third 
rings of the body; whilft, in the mean time, 
the reft, that is, the lower part of the body 
and the tail, are confiderably diminifhed and 
contracted, c. This is the beft ftate in which to 
fkin the Caterpillar, which I would have well 
obferved; for it is for this reafon only I have 
faid before, that, in order to make the intended 
experiments, one muft chufe a Caterpillar when 
near the time of changing its fkin: fuch is that 
which I delineate in this figure. 
To explain in a clearer method this funda- 
mental propofition, that the Butterfly is con- 
tained in the Caterpillar; or, otherwife, that 
the Caterpillar is the Butterfly itfelf; we muft 
carefully obferve, that after all the limbs of 
the Butterfly are fufficiently increafed within 
the external {kin of the Caterpillar, wherewith 
they are yet kept invefted, the Caterpillar at 
length, when about to undergo its change, be- 
takes itfelf to fome retired place, in which it 
may fecurely caft off its outward fkin. With 
this defign the Caterpillar firft fixes itfelf, by 
only a thin and flight web, to a board, tree, 
plant, wall, beam, N°.IV. dd, or any other 
folid fubftance; and after this, fixing the claws 
of its two hinder legs in this web, e, it imme- 
diately {pins very carefully a ftrong double 
thread, or ligament, which it draws acrofs its 
back, and faftens it with the former fuperficial 
web againft the beam or wall in two diftinct 
places, ff: fo that the fore-part of the Cater- 
pillar’s body hangs in this ligament as in a 
wreath ; whilft, in the mean time, the hinder 
part lies fixed in the fuperficial web, faftened 
to the beam. 
In confidering this Caterpillar, it muft be 
carefully obferved, that it lays the faid wreath 
fomewhat obliquely, and about the fore-part 
of its body. And hence it happens, that when 
the fkin of this Caterpillar, lying under this 
wreath, is turned back and caft off, the wreath 
itfelf is not thrufted nrore towards the hinder 
parts than to the middle of the body; it being 
there faftened a little to the foft {kin, and dried. 
Hence this remarkable advantage arifes to the 
Caterpillar, when ftript of its fin, that it 
hangs, as it were, in equilibrio. The Cater- 
pillar, having thus difpofed all thefe matters 
with this appearance of judgment and difcre- 
tion, is obferved to ceafe all action and motion 
of its limbs, and to compofe itfelf in the moft 
profound reft. 
- Immediately afterwards, or within the {pace 
of twenty-four hours, about the fore-part of 
the head, it may be obferved, that its limbs, 
being now fully enlarged under the fkin, begin, 
ab- NWA) DU R E wiorg 
by the very flow and gentle tran{portation and 
appulfe of the blood and humours, to be dif 
tended, extended, and inflated in fuch a man- 
ner, as to fwell even beyond the level of the 
{kin, and, by thus raifing the fkin, it ftretches 
it, and makes it fhine. On the other hand, it 
is obferved, that, at the fame time, the hinder 
parts of the Caterpillar’s body decreafe in fize 
in their turn, in the fame meaftre, and exactly 
in equal proportion, and become regularly fo 
much {maller. Hence all power of motion is 
immediately taken away from the fixteen legs 
of the Caterpillar, fo that it can afterwards 
neither creep nor ftand. 
At length this inflation or fwelling of the 
limbs, and other parts, which are at this time 
forming themfelves, and, as it were, budding 
out into a Chryfalis, proceeds fo far, that the 
external skin opens on the back, and afierwards 
in three diftinét places in the head, and begins 
to be drawn off, and rolled away from the fore 
towards the hinder end of the body: and, by 
this means, all the limbs enclofed within prefene 
themfelves to view. ‘Thefe limbs and parts, be- 
ing then difpofed, according to a certain neceffiry 
order, and unchangeable rule of nature, the crea- 
ture aflumes the form of a Chryfalis, reprefented 
under No. V. This Chryfalis isan infe&t with- 
out motion; and indeed it cannot be otherwife, 
for its limbs are ali incapable of motion: this is 
neceflarily occafioned by the impelled blood, 
and other humours, diftending them : add to this, 
that the limbs are drawn downwards by the fe- 
parating skin, and a great part of them likewife 
are extended. Nor indeed is this skin drawn off 
eafily; nay, not without great labour and diffi- 
culty: for all the complications of fibres, by 
which the upper is joined to the under skin, are 
then broken. For this reafon alfo, the Cater- 
pillar draws itfelf at that time one way and ano- 
ther, with an undulatory motion, and by the 
tremulous palpitation of the rings of its body. 
By this violence, at length, a limpid kind of 
ichor or humour is diftufed between thefe 
two skins, and the Caterpillar then, at length, 
cafts off the the old one. This procefs is per- 
fected very expeditioufly, after the opening is 
made in the fkull. ‘Thus I have briefly, bur 
exaCtly, defcribed how this Caterpillar affumes 
the form of a Chryfalis; the feveral parts of 
which are however feen with greater difficulty, 
than thofe of the Nymph. 
On the other hand, when this Chryfalis, or 
rather, to {peak properly, the involved Butterfly, 
is drawn out of its kin, by means of hot water, 
it has a quite different form, as may be feen in 
Figure 11. where it is reprefented laid on its belly: 
and this is yet more perfectly illuftrated in Fig. 
111. which prefents it lying on its back, fhewing 
thus all its limbs. But becaufe thefe delicate 
parts cannot be fo well diftinguifhed by thofe 
whoare unaccuftomedtofuchrefearches, inorder to 
reprefent them the more plainly, 1 have delineated 
them, and marked them with diftindt letters in 
Fig. iv. It may eafily be obferved there, how 
that Butterfly, which | have drawn out from the 
{kin of the Caterpillar, is provided with all thofe 
members, 
