THE SMALL ERMINE MOTH. 443 



and march like disciplined armies to the attack, invading a 

 district and completely devastating it before they proceed to 

 another. 



They live in largo tents, placed among the branches of some 

 tree, and composed of silken threads, -which are loosely crossed 

 and recrossed in various directions. From this centre the cater- 

 pillars issue in vast numbers, each individual spinning a strong 

 silken thread as it proceeds, which acts as a guide to the nest, 

 just as the fabled clue led through the ihtricades of Eosamond's 

 bower. When once these caterpillars have taken possession of 

 a tree, they are sure to strip it of its leaves as completely as if 

 the foliage had been plucked by hand. It is a very curious 

 sight to watch the systematic manner in which these troublesome 

 insects set about their work, how they send out pioneers which 

 lead the way to new branches, either by crawling up to them or 

 by lowering themselves to them by means of their silken life- 

 lines, and how soon they are followed by their ever hungry 

 companions. 



Perhaps the reader may wonder why the little birds do not 

 eat these caterpillars. When they have nearly stripped the 

 branch, they are very conspicuous, especially as they make their 

 way from bough to bough along their silken bridges. Indeed, a 

 proprietor of a garden that was much damaged by this moth did 

 once mention the immunity of the caterpillars as a proof that 

 any tenderness to small birds was misplaced, saying that if the 

 sparrows were half as insectivorous as I mentioned, they would 

 long ago have eaten all the caterpillars. 



Now, at the first glance, there seemed to be some reason in 

 this remark; but a short look at one of the damaged trees 

 explained the reason why the sparrows did not eat the cater- 

 pillars. The birds literally dared not approach the insects ; for 

 the silken threads which traversed the branches in all directions 

 were an effectual barrier, striking against the wings and ter- 

 rifying the poor birds. We all know that a few threads of fine 

 cotton passed from bough to bough of a gooseberiy-bush will 

 deter any little bird from settling on it; and, in the same 

 manner, the silken threads of the caterpillars deter the birds 

 from settling on the branches. These threads are very elastic, 

 and of marvellous strength, considering their tenuity, producing 

 most uncomfortable sensations when tbey come across the face, 



