A branch of Betula alba Linn. 



(Half nat. size.) 

 Galled by 



Eriophyes rudis Canest. 



This specimen is introduced for the purpose of illustrating 

 the mode of growth of examples of these galls which develop 

 from the side of a branch, and the appearance of one as seen 

 from above. 



The branch continues its growth beyond the galled area, 

 and does not appear to be stunted or weakened in vigour by 

 reason of the attacks of the mites. 



It weighed 28 oz. avoir. 



Vertical sections of it are shown in the, next plate. 



The illustration is of a specimen from a tree at Guestling, by 

 the author. 



