INSECT PESTS OF TIMBEE 117 



important organs of every tree ; wittout ttem 

 nourishment cannot take place, growth is arrested 

 and the tree may be seriously injured or even 

 killed. The gardener is alive to the necessity 

 of conserving the leaves of his charges, the forester 

 is frequently careless of their welfare till too 

 late. 



Another and less frequent source of leaf 

 damage is caused by Aphides, of which the 

 common green fly is an example. The Aphides 

 are all provided with a rostrum or beak, in short 

 an awl-shaped sucking mouth which they plunge 

 deep into the plant tissue and through which 

 they suck up the plant juices. Nutriment which 

 should properly go to the upbuilding of the tree 

 is diverted by the Aphides to their own use, 

 with results similar to those caused by the leaf- 

 eating insects. 



Conifers are liable to attack by insects which 

 bore into the extreme tips of the stems. At 

 best this form of insect attack causes the end 

 of the tree to bend over or become distorted. 

 As the chief merit of many of these trees is 

 their erect growth, it is evident that a visitation 

 by these insects is productive of considerable 

 damage. 



Another group of insects are known as Girdlers 

 from their habit of removing a ring of bark 

 from the tree which they may favour with their 



