64 NEW YORK STATE MUSEUM 
tion showed a very large proportion of the twigs to be badly affected+ 
The extent of the infestation is indicated in figure 9, a drawing 
made from one of the samples. Mr A. D. Tilton of the entomology 
department, Massachusetts Agricultural College, submitted an oak 
twig showing a very serious infestation and stated that the insect 
had killed the tree. 



Fig. 9 Ribbed bud gall, Andricus 
gemmarius Ashm. Badly infested 
twig and one gall enlarged. (Original) 
The deformations following attack by this insect are so large and 
irregular, practically girdling the twigs in many cases, that they 
probably seriously interrupt the flow of the sap and weaken the 
portion of the limbs beyond the point of injury to such an extent 
that in a few years they are likely to break off. The developing 
