Plate M. 



Eriophyes sp., (under surface) Populus 



grandiUentata . 

 Eriophyes sp., (upper surface) Populus 



grandidentera. 



3. Eriophyes sp., Populus tremuloides . 



4. Eriophyes sp., Tilia Europea. 



5. Eriophyes sp . , Betula papyrifera. 



6. Phld'coptes aceris, Acer saccharum . 



