AGRICULTURAL EXPERIMENT STATION. 



121 



FIG 3. 



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

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

 prey upon the larvae. In Fig 3 is shown one of these parasites 

 magnified, the crossed lines showing the natural size. 



THE OYSTER-SHELL BARK-LOUSE 



Mytilaspis j)omorum^ Bouche. 

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

 received during the seas m regarding it fiom other parts of the 

 State. It is a native of Euiope iutroduced into this country on 

 nursery stock nearly a hundred years ago, and is now widely 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 brownisli 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.) 



F[G 4 



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

 shown in the figure the bark is sometimes densely covered with the 

 insects, producing great injury to the tree. 



