50 



NEW YORK STATE MUSEUM 



MORE IMPORTANT SHADE TREE PESTS 

 It is exceedingly difficult to draw a sharp line between insects of prime 

 economic importance and others. An attempt has been made to do this 

 simply for the purpose of making the contents of this work more accessible 

 to the general reader. Some of the species listed under this head could 

 almost with equal propriety be included with those affecting forest trees, 

 and as a matter of fact no sharp line can be drawn between the two, though 

 there are insects which are much more destructive by reason of their depre- 

 dations upon certain forest trees used to adorn our streets and parks rather 

 than because of their injuries to the same species in a wild state. 



DESTRUCTr\"E BORERS 



This includes a number of borers affecting some of our more valuable 

 shade trees, and the different species may be identified by aid of the follow- 

 ing tabular statement. 



Key to destructive borers 



Affecting living sugar maples only, making broad, shallow galleries in sapwood just under 

 the bark; a large, fleshy, legless grub 



Sugar maple borer, Plagionotus speciosus, p. 51 

 Affecting hard and soft maples, causing deformities in the trunk and many small, brown- 

 ish, powdery borings about the places injured... Maple sesian, Sesia acerni, p. 56 

 Boring in small twigs of maple and oaks, causing the tips of the branches to fall, the broken 

 ends having a large proportion smoothly cut 



Maple and oak twig pruner, E 1 a p h i d i o n v i 1 1 o s u m, p. 59 

 Diseased or nearly dead maple, elm and other trees having medium, pencil-sized borings, 

 with frequently many galleries coming out at nearly right angles to the bark 



Pigeon tremex, T r e m e x coin m b a, p. 61 

 A dark brown or black, rather stout, cylindric beetle about yi inch long makes circular 

 sometimes spiral galleries in the roots of underground stems of sugar maple, huckle- 

 berry and a number of shrubs 



Sugar maple timber beetle, C o r t h y 1 u s p u n c t a t i s s i m u s, p. 65 

 American elms with dead and dying limbs, usually with the sapwood badly scored by 



rather large, flat, legless borers Elm borer, Saperda tridental a, p. 67 



A small, reddish beetle about ^ of an inch long and prettily marked with three yel- 

 low, nearly transverse lines on each wing cover, may be bred from wood infested 

 by the elm borer Neoclytus erythrocephalus, p. 71 



