Thea oH, # SF Or ¥. oh 1-NS BF GTS, 
fubftance, in a manner, takes up all the infide 
of the Caterpillar, not filled by the ftomach, 
' the head and tail not excepted. It is of a yel- 
lowifh colour; but here and there inclines to 
white. As to its form, it looks like a congeries 
of little membranes, folded one over the other ; 
but differing greatly in conftruction and texture. 
‘The fat ferves to this amongft other purpofes, 
that it binds and fupports the pulmonary tubes, 
which are diftributed through it in great 
numbers. 
The pulmonary tubes arife from three re- 
markable pairs of branches, which are feen on 
each fide in the breaft, belly, and tail of the 
Caterpillar; and the pulmonary tubes, propa- 
gated from every part of thefe branches, com- 
municate with each other at every one of the 
points of refpiration. In thefe parts alfo are 
to be feen a great many ramifications of pul- 
monary tubes, which {pread themfelves all over 
the body, fo that no part of it can be afligned, 
‘not even any of its horny fubftance, that is not 
furnifhed with its pulmonary tubes. 
The beft way to fee the heart, Tab. XXXIV. 
Fig. vi. aa, of the Caterpillar, is by laying it 
on its back, and then opening the belly. It 
is then found, that this organ extends from 
one end of the body to the other. It pervades 
the tail, belly, and breaft; and thence ftretches 
very high up to the brain itfelf. This heart is 
an oblong, delicate, and flender little tube, 
which widens in fome places, and again grows 
narrower in others. It is furnifhed with fome 
pulmonary tubes, and with fome mufcular and 
fibrous hairs, which run part lengthways, and 
part croffways, and require a great deal of art 
and induftry to difcover them. ‘This tube con- 
tracts itfelf by the help of its own fibres, and 
is dilated again by the joint efforts of a pro- 
digious number of mutcles, 646666, of a 
fingular form, which grow on its outfide; 
and, though eafily feparated and diftinguifhed 
from one another, they look, at firft fight, 
as if they were but one continued mutcle. 
The defign I have given, to illuftrate the de- 
aes Dae lias Pa 
ig 
{cription of this organ, reprefents only a part 
(Om 16. 
It is no eafy tafk to get a fight of the brain 
and {pinal marrow in healthy Caterpillars, on 
account of the great quantity of fat that in- 
volves thefe parts; fo that fickly infects, or 
thofe which have been otherwife wafting for 
fome days, with conftant labour, are the fitteft 
for this purpofe. The incifion muft be made 
in the back, as the brain and {pinal marrow 
lie in the abdomen. The brain is compoied 
of two hemifpherical lobes, Fig. vi1. a, placed 
juft over the infertion of the gullet into the 
mouth ; and under thefe lobes are to be feen 
the heads of the {pinal marrow, compofed of 
_two nerves, 64, which unite at fome diftance, 
and form the firft knot or joint, c, from whence 
nerves are diftributed to the mufcular parts of 
the head. The marrow then parts again into 
two branches; and the nerves, dd, {pringing 
from thofe branches, are diftributed amongft 
the mufcles of the neck. Another conjunction 
of the main nerves forms the fecond little knot 
or joint, e, which is fomewhat lefs than the 
firft, From this fecond knot or joint iffue two 
branehes, as from the firft; and thefe branches 
unite again, to form the third joint or knot, 
whofe ramifications are difperfed amoneft the 
mufcles of the thorax. Here the marrow di- 
vides itfelf again for the third time, and runs 
in this divided form a confiderable length, f 
before it coalefces into the fourth knot or joint, 
&; to which fucceeds, after a fhorter fepara- 
tion, the fifth, 4. Thefe laft joints or knots 
fupply with nerves the mufcular parts of the 
embryo legs and wings of the future Butterfly. 
After this, the marrow parts no more; but it 
has however fix more joints or knots, befides 
thofe already taken notice of, making eleven 
in all; of which the fixth 7, the feventh &, 
the eighth /, the ninth m, and the tenth n, 
emit each four nerves, all difperfed among the 
vifcera and the mufcular parts of the abdomen. 
Finally, the laft knot, 0, beftows all its nerves 
upon the tail. 
Il. 
Lhe manner in which tbe Caterpillar is changed into a Chryfalis ov Aurelia, with 
the true explanation of what the Chryfalis is. 
This chapter contains alfo fome 
anatomical obfervations, and fome other curious remarks concerning the Chry~ 
falis and Butterfly. 
HEN the Caterpillar has fed fuffi- 
ciently, it refts for fome time. In this 
period, all the food it has taken is thoroughly 
digefted. It then forms a pretty ftrong web 
upon the ftalks or leaves of the plant whereon 
it fed: but this web, on account of its great 
delicacy, is not eafily feen; unlefs the infe@ be 
put into a little box, with a piece of black 
“paper for it to work on. Then its web, how- 
ever flight and tender it may fometimes be, 
fhews itfelf very plainly, : 
This web being 
finithed, Tab. XXXV, Fig. 1v. 4, the Caters 
pillar ftrikes into it the claws of the two legs 
under the tail, and afterwards forces in the tail 
itfelf, by contracting thofe claws, and violently 
ftriking thofe legs again{ft one another: and, as 
foon as the tail is thus well fecured, it lets itfelf 
hang in the air, with its head downwards, by 
loofening the hold it hitherto kept of the plant 
with its other legs. 
But I think it proper to defcribe the limbs of 
the Caterpillar, that grow under its fkin, before 
eee I pro- 
