Ceoidomyia rosaria. 



No more appropriate name could be given to these galls 

 than the popular one of " rosette." 



They are not common nor are they abundant. Some 

 willows, preferably young trees and large bushes, contain a 

 goodly number, while other trees near by have none upon them. 

 They may be found on several kinds of Salix, principally on 

 ^. alba, S. aurita, S. caprea, S. cinerea, and S. purpurea. 



The rosette may consist of a cluster of thirty to sixty leaves 

 in all stages of development, about half of which are medium- 

 sized leaves, the others are very small. They are all firmly 

 attached to the twig. The outer leaves are usually slightly 

 thickened, hard, and occasionally woody. The edges roll 

 somewhat, and with age become strongly serrated. The inner 

 ones are mere imbricated leaflets ; they have a lustrous 

 appearance, due to pilosity. Within this cluster the solitary 

 larva will be found. When fully grown it will measure 3 mm. 

 long and 4 mm. in girth. A typical cluster examined in the 

 month of September consisted of twenty-eight outer leaves more 

 or less fully developed, the largest being 30 mm. long and 

 18 mm. at greatest width, all arranged around the upper 

 10 mm. of the length of the twig. Enclosed by these leaves 

 were twenty-three imbricated leaflets, the base of each being 

 attached to the extreme tip of the twig. They varied from 

 4 to 6 mm. in length, and from i;|^ to 2 mm. in width. 



