74 OUTLINES OF FORESTRY. 



eggs. In all cases the increase in the destruction 

 produced by insect life can be traced to the indis- 

 criminate and foolish slaughter of the insectivorous 

 birds that formerly held such life in check. 



Caterpillars often cause considerable destruction 

 to forest trees. 



The caterpillar of the pine bombyx often causes 

 great ravages in the pine forests. In Germany 

 these caterpillars are called pine-spinners, from the 

 great number of cocoons with which they cover 

 the pine-trees. Such caterpillars have been known 

 to completely destroy extensive pine forests. The 

 foresters are often compelled to set fire to portions, 

 of the forests in order to prevent the too rapid 

 multiplication of this pest. 



Another caterpillar, which from its black and 

 white coating is sometimes called the monk or 

 nun caterpillar, is equally destructive, not only to 

 forest trees like the pine, but also the other forest 

 trees, such as the beech, oak, and birch. 



Other caterpillars cause great destruction to the 

 forest by eating the tender buds or the young 

 shoots. 







Grasshoppers often cause considerable damage 

 to young trees by devouring the leaves, herbs, and 

 tender shoots. 



