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were it not for the 'boring insects and the fungi by which they are almost invaria'-. - 

 attacked. The insects are the chief agent in the destruction of the timber, and ti. 

 prevention of fire may be properly considered a method of insect control. In an- 

 other sense fire and insects may be sometimes directly related. Forest insects, 

 such as certain bark-beetles and Ihe larch saw-fly, kilM outright large bodies of 

 timber. It is altogether likely that serious fires at times originate in areas of su'' ; 

 dry, insect — killed trees. 



The insects which are so injurious to fire-killed timber are adults and th 

 young or larvae of boring beetles belonging mainly to the families Buprestidae, 

 Cerambycidae and Ipidae (Scolytidae). They are often responsible for serious 

 injury to logs and to injured and dying trees wherever found. A considerable 

 number of species attack trees that are apparently in perfect health and are among 

 our most destructive forest and shade tree pests. 



The Buprestidae, or Metallic Wood Borers, are large or medium sized, flatten- 

 ed beetles, with bluish black or bronze metallic colours. They deposit their eggs 

 in slits or crevices in the bark during the snmmer months. The young or grubs 

 excavate, tunnels in the bark and wood. These grubs have the segments imme- 

 diately behind the head considerably widened and flattened, and have received the 

 appropriate name of Flat-headed Borers. They are very abundant in both hard 

 and soft wood trees. One of the most injurious is the Bronze Birch Borer, Agri- 

 Ins auxins, the worst enemy of our imported cut-leafed birches. The grubs of 

 this species cut long, winding tunnels through the inner tark and sapwood of the 

 trunks and branches of ali sizes. The infestation is first apparent from the rusty 

 patches on the bark caused by the overflowing sap from the tunnel being cut be- 

 neath. The trees begin to die first at the top. The removal of these dead tops 

 has no beneficial effect, for the borers are by that time working in all parts of the 

 tree. The life of the trees may be prolonged by examining the trees during the 

 fall and spring and removing with a sharp knife the borers working beneath the 

 rusty patches on the bark. All badly infested trees should be cut and completely 

 burned during winter or early spring to destroy the grubs before they can emerge 

 and spread the infestation. 



The Cerambycidae, or Long-horned, or Longicorn Beetles, are large, medium- 

 sized, usually cylindric beetles, with long antennae or feelers. Many species breed 

 in the bark and wood of injured and dying trees and logs. The breeding habits 

 are similar to the of the Metallic Wood Borers. Certain species of the Longi- 

 corns spend two or three years in the wood as grubs. The grubs are cylindric, 

 with the segments immediately behind the head swollen but not much flattened, 

 and they are known as "round-headed borers". The grubs of most species breed 

 in weakened or dying trees and logs ; but certain others cut their tunnels in per- 

 fectly sound trees. The Poplar borer, Saperda calcarata, is a destructive borer in 

 poplars throughout all parts of Canada. The Locust Borer, Cyllcne rohiniae, ex- 

 cavates its larval tunnels in the wood of Locust trees and Acacias. It is a most 

 destructive pest. 



Ipidae (Scolytidae) affect timber in two ways. The true Bark beetles, such 

 as Dcndroctonus, Ips and Polygraplms, cut their tunnels in the inner bark or be- 

 tween the bark and the wood. When they work in living trees the sap flow is 

 checked with fatal results to the trees. They do not penetrate deep into the wood, 

 and consequently do not directly injure the timber. There are destructive species 

 in all our Canadian forests which attack and kill weakened and -even healthy trees. 



