GIPSY MOTH AND BROWN-TAIL MOTH, 



13 



Thaxter in 18SS. Like all diseases of this nature, the benefit derived 

 from it is regulated largely by favorable or unfavorable weather 

 conditions. This fungus sometimes works to a slight degree on the 

 small caterpillars in the fall, and in some instances it is found in the 

 winter webs. As a rule, however, the greatest mortality of cater- 

 pillars takes place in the spring, when they are nearly full-grown, 

 and the ])up?e of the moth, under the most favorable conditions, 



Fig. G.— Red oak trees stripped by brown-tail moth caterpillars. Note old winter webs at tops of trees. 



