THE CATERPILLAR. 
35 
composed of a number of leaves folded one witliin 
the other. The outer leaf is hard and horny from 
exposure to the air, but the inner ones are quite 
soft and pulpy. After a time, the inner leaves 
grow larger and stronger, and spread out into the 
flower; but the outer leaf remains the same, and 
being a mere sheath, is often cast off as useless. 
Very much the same thing happens in the case 
of the caterpillar. It has several skins, one within 
the other; the inner ones soft and delicate, and 
the outer one hard, by exposure to the air. The 
caterpillar grows very fast, but the outer skin 
does not keep pace with it. It is like the sheath 
of the flower, and has to burst and let the next 
skin come to light. When this is going to 
happen, the caterpillar leaves off eating; for 
there is no room in the tight old skin to hold 
any more food. It begins to be uncomfortable, 
and wriggles itself about, as if it were in a 
strait waistcoat. At length, it makes a slit, 
generally behind the head, and forces itself through 
the rent, drawing out its feet as if it were drawing 
them out of a glove. It comes out very damp, 
and if it is a hairy caterpillar, there will be new 
hairs upon the new skin, lying folded down like 
little wet tufts. But the hairs and the skin soon 
get dry, and the creature looks much fresher and 
brighter than it did before. It is more hungry 
