of 



single infested tree may in a year or two spread 

 destruction through thousands of acres of forest. 



Most insects have enemies to bite them. The 

 ichneumon-fly spreads death among injurious 

 grubs. Efforts to control forest-enemies will 

 embrace the giving of aid and comfort to those 

 insects that prey upon them. Bugs will be 

 hunted with bugs. Already the gypsy moth in 

 the East is being fought in this way. Many 

 species of birds feed freely upon weevils, borers, 

 and beetles. Of these birds, the woodpeckers 

 are the most important. They must be protected 

 and encouraged. 



There are other methods of fighting the enemy. 

 A striking and successful device for putting an 

 end to the spruce-destroying beetle is to hack- 

 girdle a spruce here and there in the forest at a 

 season when the physiological make-up of the 

 tree will cause it to change into a condition most 

 favorable for the attraction of beetles. Like 

 carrion, this changed condition appears to be 

 scented from all quarters and afar. Swarms of 

 beetles concentrate their attack upon this tree 

 and bury themselves in it and deposit their eggs. 



188 



