1905.] Gall-Gnats on Osiers and Willows. 



501 



The remedial measure is to cut away and burn the galls 

 before the flight of the adults. 



Fig. 2. 



Fig. 4. Fig. 3, 



Fig. 2. — Larva of C. saliciperda, after preservation, greatly magnified. 

 Fig. 3. — Longitudinal section of Salix alba, showing larval tunnels of 

 C. saliciperda, natural size. Fig. 4. — Piece of Salix alba, showing flight 

 holes of adult C. saliciperda, natural size. 



Cecidomyia (Rhabdophaga) rosaria. 



The galls of this insect are typical of a series, where, owing to 

 the malformations at the ends of the twigs, the normal increase 

 in length is hindered. The galls of C. rosaria are rose-shaped, 

 and are found at the ends of the shoots of 5. caprea, S. aurita, 

 S. alba, S. purpurea, and S. cinerea. The fly is black, with 

 greyish wings, and has silvery hairs on the thorax. 



In late spring or early summer the egg is laid in the 

 developing terminal bud, and the internodes failing to develop 

 the leaves remain drawn together in a rosette. 



