List of the Insect Fauna of the County. 



149 



These galls are multilocular ; the larvae pupate in the gall, 

 and the images emerge therefrom in May. Cecidomyia 

 Salicis, Schrank. 



Salix Caprea, L. Leaf. Small, hard, pustular galls, 

 occurring on the side veins of the leaf, often in considerable 

 numbers ; they are about the size of a small hemp-seed when 

 single and mature ; are conical in shape, projecting both on 

 the upper and under side of the leaf; are hard and woody, 

 and pale greenish in colour. The gall is single-celled, but 

 we very commonly find large numbers confluent together ; 

 sometimes the gall takes the form of a much-thickened, hard 

 midrib, extending the whole length of the leaf, and occupying 

 half its extent ; often yellowish or red in colour. Such galls 

 are frequently left attached to the twigs during winter, and 

 then show the numerous small round holes from which the 

 larvffi have emerged ; they leave the galls in autumn and 

 pupate in the earth, the flies appearing in May. Hormomyia 

 CAPREA, Winnertz. 



Salix Caprea, L. Leaf. Eound, hairy, green, rarely 

 reddish, thin -walled, succulent galls, occurring on the under 

 side of the leaf, attached only at 

 one point, and showing as a dis- 

 coloured spot above. In rare cases 

 the gall is produced on the upper 

 side of the leaf, and then is smooth 

 and rosy. Each gall is tenanted 

 by a single larva, which eats a 

 small circular hole through, and 

 quits it in September ; it pupates 

 in a cocoon in the earth, and the 

 sawfly appears in May or June. 

 Nematus viminalis, Linne. (Fig. 50. ) 

 We probably have other "pea" 

 gall-makers in the county, but 



these closely- allied Nemati and their distinctive galls are but 

 indiflerently known in this country. The sallow " rosette " 

 galls are also probably distinct from those above referred to, 

 as occurring on 8. alba, S. fnujilis, &c. 



Fig. 50. Nematus vimiiuiUs. 



