45 ° 
THE BUTTERFLSr. 
fore thcfc develope, the outer (kin is feen to wither and 
lofe the vivacity of its colours, owing to a new coat 
•which already covers the animal beneath, and intercepts 
the juices which formerly circulated through it: After 
fome efforts, this dried covering is rent towards the back 
part of the head, where a frefn (kin appears ; and through 
this aperture, the worm makes his cfcape leaving his 
fpoils behind *. 
After undergoing feveral changes of this kind, the a- 
pimal prepares to undergo another ftill more confiderable, 
which is to introduce it into the (late of a chryfalid, deprived 
of almofl all motion, and incapable of taking food. This 
change is eff iffed nearly in the fame manner as the fore- 
going; but in fome it is very long in being accompliflied- 
Several fpecies of the butterfly worm, conflrr.ct in a very 
ingenious manner a coque or nut of filk, into which they 
enter before their transformation, and in which they con- 
tinue for nine months, without food, before their meta- 
morphofes be accompliflied f. During this long period, 
they are apparently inanimate, and take no food. 
Various fubftances enter into the compofition of the 
habitations conftructed by thefe animals before their me* 
tamorphofes ; fome are of filk ; in others that is combined 
with other matter ; feveral kinds conflrudl no habitation, 
but are protected by a cruflaceous (hell, formed by a glu- 
tinous fubftance, exfuding from their bodies : Some are 
fufpended vertically, while others hang horizontally by 
a thread which furrounds the middle of the body %• 
The external form of the chryfalids varies according to 
the fpecies of butterfly that inhabits them ; in all, howe- 
ver, there are apertures oppofitc to the thorax, by which 
3 refpiratioq 
a Reaumur, Tome I. mem. 3. 
,f Idem Tome I. mem. 11 & 1 3. 
■}■ Tome II. mcm, I. 
