saving from their service is enormous. Although 

 this cannot be estimated, it can hardly be over- 

 stated. 



A single borer may kill a tree; so, too, may 

 a few beetles; while a small number of weevils 

 will injure and stunt a tree so that it is left an 

 easy victim for other insects. Borers, beetles, 

 and weevils are among the worst enemies of 

 trees. They multiply with astounding rapidity 

 and annually kill millions of scattered trees. 

 Annually, too, there are numerous outbreaks 

 of beetles, whose depredations extend over hun- 

 dreds and occasionally over thousands of acres. 

 Caterpillars, moths, and saw-flies are exceed- 

 ingly injurious tree-pests, but they damage the 

 outer parts of the tree. Both they and their eggs 

 are easily accessible to many kinds of birds, 

 including the woodpeckers; but borers, beetles, 

 and weevils live and deposit their eggs in the 

 very vitals of the tree. In the tree's vitals, pro- 

 tected by a heavy barrier of wood or bark, they 

 are secure from the beaks and claws of all birds 

 except Dr. Woodpecker, the chief surgeon of 

 the forest. About the only opportunity that 



