4 
THE ART OF REARING 
be sensibly shortened or lengthened ; the others, 
whether two, four, six, eight, or ten in number, 
are membranous, flexible, and attached in pairs 
to the back part of the body, under their corre- 
sponding rings. 
These last legs are those which transport the 
animal ; they are provided with little hooks, to- 
lerably strong, calculated to give him support, 
and enable him to climb. All the hinder legs 
disappear, of whatever kind the caterpillar may 
be, when it changes into a butterfly, and there 
remain only the six first, which are variously 
•modified. The anus is placed under the last 
ring. Caterpillars breathe by eighteen aper- 
tures, situated nine on each side of the body, 
through which the air passes in and out. Each of 
these openings is considered as the termination of 
a particular windpipe. A great number of cater- 
pillars have eyes ; some of them are utterly blind, 
but they acquire the power of vision when they 
attain the state of butterflies. Having pointed 
out the general external characters which distin- 
guish caterpillars from all other animals, it would 
seem useless to mention that some, according to 
their different kind, are large, middling, and small; 
but however they are all very large, compared 
with the egg from which they are produced, or 
with themselves at the moment they emerge from 
the egg, as will be seen in Chapter VII. 
