144 INSECTS INJURIOUS TO THE PEAR. 



August lias passed. The hole made by the beetle when it is 

 escaping is a little more than one-twentieth of an inch in 

 diameter. 



It was formerly su])posed that these insects infested only 

 such trees as were unhealthy or were already dying, but it has 

 been stated that sound and healtliy trees are attacked and 

 severely injured by them. Neither are they limited in their 

 operations to the twigs, but sometimes attack the trunk also. 

 It is said that there are two broods each year, the early one 

 nurtured in the trunk, and when these reach maturity, the 

 newly-grown twigs, offering a more dainty repast, are subse- 

 quently invaded and destroyed. 



The injuries inflicted by this insect are not confined wholly 

 to the pear; occasionally it is found on the apple, apricot, 

 and plum. The only remedy which has been suggested is to 

 cut off the blighted limbs below the injured part and burn 

 them before the beetle has escaped. 



The damage caused by this insect must not be confounded 

 with the well-known fire-blight on the pear, since that, as 

 already remarked, is a disease of a totally different charactei", 

 and is entirely independent of insect agency. 



No. 69. — The Pear-tree Bark-louse. 



Lecanium pyri (Schrank). 



This insect is found on the under side of the limbs of young 

 and thrifty pear-trees, adhering closely to the bark. It ap- 

 pears in the form of a hemispherical scale about one-fifth of 

 an inch in diameter, of a chestnut-brown color, sometimes 

 marked with faint blackisli streaks, and having on its surface 

 some shallow indentations. The outer margin is wrinkled. 

 These scales, when mature, are the dead bodies of the females 

 covering and protecting their young ; some are darker in color 

 than others, and there are some smaller ones which are of a 

 dull-yellow hue. 



Under the scales the young lice are interspersed through a 

 massof white cotton-like matter, which subsequently increases 



