ie NATURAL HISTORY. 
feveral forts from each other; and yet they are all perfe& in their kinds: 
However they are all compofed of feveral rings, which being either 
extended or contracted, enable them to carry their bodies where ever’ 
they have oceafion to go. ‘They have a certain number of feet with’ 
joints, and are armed with hooks, wherewith they fix themfelves to 
the barks of trees, efpecially when they fleep, which is the time they 
pafs from one ftate to the other. They have almoft all threads com- 
pofed of a fluid gummy matter, which they get out of the leaves that 
fupply them with food. When they perceive any danger of being car-"_ 
ried off by birds, or crufhed by the motions of the branches, they fix: 
themfelves to the trees by means of. this gum, which is made into 
threads by feveral openings of their bodies, which threads they unite 
with their paws, and form feveral into one, capable of fupporting their 
own' weight,, and fo are generally fecure from danger. Some natura- 
lifts believe,. that the colour of the Caterpillars is one of the belt pre- 
fervatives againft the birds that are fond of feeding upon them; for’ 
they generally are of the fame principal colour as the leaves whereon’ 
they feed, or of the fmall branches to which they are fixed, when they | 
undergo the metamorphofis; thus, thofe that are nourifhed on the 
buckthorn-tree are as green as the leaves thereof, and thofe that live 
upon apple-trees and. bufhes are. of the fame colour as the bark of thofe’ 
plants. [Even the fmalleft of thofe animals have methods of fereening 
themfelves from the purfuit of the birds ;. for they may be often found: 
under the léaves and-not above, where they would be more expofed. 
All forts of Caterpillars ufe a:particular kind of nourifhment,. which 
they never change upon any account whatever ; for though they live. 
npon greens, each has its own plant,.and will fooner die than feed up- 
on any other, unlefs they are nearly of the fame. Towards the end of 
the fummer, when Caterpillars Have fufficiently fed on the green leaves,: 
then they leave off. eating, and.fecure a retreat, where they undergo 
the fucceeding changes. A few days are fufficient for fome to undergo’ 
this metamorphofis, while others continue months, and even years in: 
their coffins.. Some. at this time hide themfelves in the ground, and 
others get upon the roofs of. houfes,-in the holes of walls, under the 
park of trees, and even into the heart of the wood ;-others again, wrap’ 
themfelves up in threads and gum, and rowling themfelves in the fand, 
make themfelves a fort of ftone coffins. Likewife,. fome reduce little 
bits of wood to powder,.and with their gum make a covering in which’ 
they wrap themfelves ; and when it is quite formed,.it is not much un- 
like an Egyptian mummy. 
Some forts of Caterpillars are capable of {pinning threads, in which’ 
they are covered and defended from the rain, particularly Sik-worms, : 
of which more hefeafter.. The moft common fort of Caterpillars are’ 
thofe that we mect with on elms, apple-trees, and bufhes; and the But- 
terfliés that proceed from them, fix upon fome entire leaf, where they 
lay their eggs in the autumn, and die foon after; but before winter 
they are hatched and become: fmall Caterpillars, which with their 
threads make themielves beds and fpacious lodgings, where they lie 
during the cold feafon, diftributed as it were in different rooms with- 
out eating, or-coming out. ‘Their coverings are as hard as parch- 
ment, and confequently fufficient to keep off the rain, wind, and cold; 
for they lie upon a fort of thick down, and are furrounded with erat 
eS" 
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