LEPIDOPTERA. 147 
with stinging bristles, which cause such smarting and itching to 
our skin, and produce blisters upon it ? 
It has often been said that each plant has its own peculiar species 
of caterpillar. All we can say is, that a certain number of vege- 
tables only suit certain caterpillars. The species which eat roots 
are few; those which live in the interior of stalks or stems which 
they feed on are numerous, and those which nourish themselves 
on the pulp of fruits are rare. In general, after the leaves, the 
caterpillars prefer the flowers ; in this they certainly do not show 
bad taste. Their growth is more or less rapid, according to the 
species, according to the nourishment they take, and according 
to the season of the year. ‘Those whose food is succulent, grow 
more rapidly than those which have for their food dry gramineous 
plants and coriaceous lichens. Most of them eat at night, and 
remain during the day motionless, and as it were in a state of 
torpor; others are so voracious that they are constantly eating. 
This voracity is indeed sometimes surprising. Malpighi has 
observed that a silkworm often eats in a day mulberry leaves 
equal to its own weight. How could we provide our horses and 
oxen with provender, if they required each day their own weight 
of hay and grass? There are even some caterpillars which are 
still more voracious than that. Réaumur weighed several cater- 
pillars of a species which lives on the cabbage, and gave them bits 
of cabbage leaves which weighed twice as much as their bodies. 
Tn less than twenty-four hours they had entirely consumed them. 
In this space of time their weight increased one-tenth. Fancy 
a man whose weight is 180 lbs. eating in one day 360 lbs. of 
meat, and gaining 18 lbs. in weight! Caterpillars eat by the aid 
of two jaws, or mandibles, so broad and solid that, considering the 
smallness of the insect, they are equivalent to all the teeth with 
which large animals are furnished. It is by the alternate move- 
ment of these mandibles that the caterpillars devour the leaves 
with so much greediness and ease. 
“ A caterpillar, when it wants to gnaw the edge of a leaf,” says 
Réaumur, “ twists its body in such a way that at least one portion 
of the edge of this leaf is passed between its legs. These legs 
hold fast that portion of the leaf which is to be cut by the insect’s 
jaws (Fig. 191). To give the first bite, the caterpillar elongates 
L2 
