268 OUR INSECT FRIENDS AND FOES 



in that state until the following spring, although 

 a certain proportion complete their metamor- 

 phosis by the end of the summer. These Elm- 

 bark Beetles are small black insects, about an 

 eighth to a quarter of an inch long, and have their 

 wing-cases pitted lengthwise with rows of dots. 

 Of an even more serious character are the 

 depredations of the caterpillars of the Goat 

 Moth (Cossus ligniperda), which not only attacks 

 the elm and ash, but also the oak, beech, 

 lime, willow, and poplar trees. These insects 

 remain for three years in the caterpillar stage, 

 attaining a length of three or more inches ; they 

 live within the tree for the whole period, 

 gnawing tunnels and chambers of various size 

 and width, some as large as a man's middle 

 finger, right into the solid wood, and causing 

 such serious injury as to kill the tree. These 

 caterpillars have gained their popular name 

 from their very unpleasant smell, which is so 

 strong as to impregnate their burrows. The 

 female moth deposits her eggs on the bark close 

 to the base of the tree, and from thence the 

 larvae, on emerging from the eggs, eat their 

 way into the tree. Some idea of the depreda- 

 tions of burrowing beetles, like the Ash and 

 Elm-bark Beetles, is gained when we learn that 

 in the year 1837 no less than 20,000 feet of oak 

 trees, varying in age from thirty to forty years, 

 had to be cut down in the Bois de Vincennes, as 

 they were completely ruined by the attacks of the 

 bark-burrowing beetles; while in the year 1783 

 these insects were responsible for the destruc- 

 tion of 1,500,000 trees in the forest of Hartz. 



