AGRICULTURA.L EXPERIMENT STATION. 

 FIS. 3. 



157 



This pest is held in check by woodpeckers and insect parasite. 

 Several species of four-winged flies called Ichneumons are known to 

 prej' upon the larva. In Fig. 3 is shown one of these parasites 

 magnified, the crossed lines showing the natural size. 



THE OYSTER-SHELL BARK-LOUSE. 



Mytilaspis pomorum, Bouche. 

 This pest is quite common about Orono, and letters have been 

 received during the season regarding it from other parts of the 

 State. It is a native of Europe introduced into this country' on 

 nurser}^ stock nearly a hundred years ago, and is now widel}- dis- 

 tributed, doing great damage to the apple tree, and is known to 

 affect the pear, plum and currant. It can be detected with the 

 naked eye as minute brownish or greyish scales nearly the color of 

 the bark. These scales are about one-sixth of an inch long, shaped 

 somewhat like an oyster shell, and placed on the branches or twigs 

 lengthwise with the small end usually upward. (Fig. 4.) 



FIG. 4. 



Fig 5-7 shows the under side of the female scale enlarged. As 

 showa in the figure the bark is sometimes densely covfired with the 

 insects, producing great injury to the tree. 



