(43) 



destroying the worms, while those in the forests remain 

 undisturbed. This difficulty can be obviated by allowing 

 cattle or sheep to range the ground. 



In the year 1850 the forests of New York suffered much 

 from this insect, but afterwards escaped, owing probably 

 to the presence of a parasite in the pupae, which proved 

 to be a small Ichneumon fly. 



jEgeria acerni. (CLEMENS.) THE LEGGED-MAPLE BORER. 

 (LEPIDOPTERA ^EGERIID^E.) 



The Maple trees used for shade are injured by this 

 borer to some extent in Peoria. The eggs are deposited 

 during the latter part of May, or even later, in the crevices 

 of the bark. As soon as the eggs hatch the worms burrow 

 under the bark, feeding on the 

 inner bark and sapwood, filling 

 the burrows with the excrement, 

 and causing the bark to crack 

 open and loosen. When occur- 

 ing in great numbers they girdle 

 the tree and kill it, while when 

 a few only attack a small tree it 

 is weakened, and liable to be 

 broken by the wind. The worm 

 when fully matured changes into 

 the chrysalis, loosely covered 

 with white silk and the brown 

 pellet excrement of the worm. 

 When ready to come forth as a 

 moth, it works its way through 



ERIA ACERNI, a, a, larva dorsal, ana . " , 



lateral views; b, b, b, cocoons ex- a hole in the bark, made by the 



posed by detachment of bark; c, 



th; d, chrysalis skin as it is often worm. 



left remaining in the hole of the exit. 



The borers are only found in the trees which have 

 already been injured by the Flat-headed Borer, Chrysobothris 

 femorata. Fabricius, or where the bark has been rubbed 

 and is cracked or roughened. A smooth bark is seldom 



