INJURIOUS INSECTS. 137 



the larvae are iu them ; otherwise it will be labor wasted. The 

 trees are rapid growers and will soon recover from a necessarily 

 vigorous pruning. If care is taken to taken to cut and burn all 

 the infested twigs in any locality, there will very likely follow a 

 period of comparative freedom from injury. 



Complaints are often made of destruction of the ornamental 

 mountain ash, hawthorns, and apple trees, by the Round- 

 headed Apple Tree Borer {Saperda Candida). This insect most 

 commonly attacks the lower part of the trunks, at or near the 

 ground. The egg-laying takes place iu June and July, and it is 

 at that time that the trunks should be covered with the soft soap 

 wash, if there is any danger of attack. 



It is said that this insect does not complete its growth, and 

 reach the perfect, or beetle, stage until the third year from the 

 time the egg is laid. Throughout this period it remains in the 

 wood, actively boring during the growing seasons. The greatest 

 danger to the life of the tree is caused while the insect is boring in 

 the sapwood, and before it goes deeper into the trunk ; because 

 the tree may thus become practically gmlled and killed, as the 

 sapwood is the most vital part, being the medium through which 

 the sap is conducted from the roots to the branches and foliage. 



The presence of the borers may often be detected by the fine 

 sawdust-like material thrown out from cracks in the bark, and the 

 well-known practice of reaching after and destroying them with a 

 flexible wire may be tried. In thin-barked trees, when the borers 

 are at work directly under the bark, they usually cause a drying 

 and discoloration of it, and the larvie may thus be located and cut 

 out. The pale brown and white striped beetles of this species are 

 not often seen, because they usually move about in the dusk, and 

 remain quiet during the day. 



The opposite of this habit is seen in the beetle of the Flat- 

 headed Apple Tree Borer (Chrysobothris femorata) , which delights 

 to bask in the sunshine on the bark of the trees ; but the color of 

 the insect harmonizes so well with the general color of the bark, 

 that it is not easily detected. This species is often more common 

 than the other, and does more widespread injury. As the name 

 indicates, the boring larva has a broad flattened head, and a com- 

 paratively slender body. 



It rarely attacks well established, vigorous, perfectly healthy 

 trees, but prefers those of feeble growth, or which are already 



