MISCHIEF CATERPILLARS CAN DO. 61 
there are some that eat the woody fibre of the 
tree itself. I have already mentioned the cater¬ 
pillar of the goat moth,* that was strong enough 
to lift the hell-glass, with the heavy hook at the 
top. It lives in the inside of trees, and gnaws 
its way to the very core, in order to make itself 
a nest. Here it scoops out a hollow place, just 
large enough for -it to lie in; and lines it with a 
substance as thick and warm as cloth, made of 
the raspings of the wood, joined together with 
silk. During the cold of winter, it remains in a 
torpid state, snugly housed within its comfortable 
nest. These caterpillars do a great deal of 
damage to the trees, and will often cause the 
stoutest timber to decay. 
The owner of an estate once observed a fine old 
elm, that had braved many a severe winter, begin 
to look unhealthy, and to lose the colour of its 
leaves. The tree kept getting worse; and no 
one could imagine what was the matter with it, 
until, one day, a caterpillar was seen to put its 
large scaly head out of a hole in the bark. The 
cause of the mischief was explained; the tree 
was evidently infested with caterpillars, and to 
prevent them getting into the neighbouring trees, 
the only thing to be done was to cut it down! 
* Cossus ligniperda. 
