BORING INSECTS 



61 



that wire netting is effective against it. Protect- 

 ive coverings should be kept on during the period 

 suggested in speaking of the bronze birch borer. 

 The flat-headed borers do immense damage to 

 coniferous forest trees, causing, for instance, the 



Round-headed apple tree borer, a, larva, from side; b, from 

 above; c, female beetle; d, pupa 



oval holes so common in cheap shingles. One or 

 two infest sycamore, oak and beech. 



Besides the flat-headed borers, the insects feed- 

 ing mainly on the wood are the timber worms, the 

 carpenter worm, and the horn-tails. Of the first 

 group, the chestnut timber worm is the most im- 

 portant. It is responsible for the holes so com- 

 monly observed in chestnut lumber. There is 

 little to be done with it directly, but preventive 

 measures, as the destruction of dead and dying 

 trees and limbs, are effective. 



