Galls caused by the larvae of Cecidomyia rosaria Lw. 



on 



the terminal leaves of Salix aurita Linn. 



PLATE S6. 



The illustration on the opposite page gives the appearance 

 of the rosettes as seen during the months of December to June, 

 and may be considered as the winter-spring form of these 

 gall-growths. 



The number of the leaves and leaflets in the rosettes caused 

 by these larvae is always greater than would be found on a 

 twig, the growth of which has not been arrested. This points 

 to the fact that the embryo leaves in the bud, which under 

 normal conditions would not develop until the following year, 

 are caused to expand and form the imbricated leaflets which 

 immediately surround the larva. 



The illustration is of specimens gathered at Hastings by 

 the author. 



