List of the hisect Fauna of the Comity, 



147 



considerably leiigtlieiied. The gall is single-celled, and when 

 mature in June falls with the catkin, hut the gall-tly does 

 not emerge therefrom until the succeeding spring. Andricus 

 QUADRiLiNEATus, Hartig. (Fig. 47.) 



l" 



Fig. 47. Andricu^^ quadriliueatus. 



Salix alba, L. Leaf. The bean- shaped galls on the leaf 

 are very common, and generally well known. They are oval 

 or bean-sha]3ed, and occur four or five in 

 a row on each side of the midrib (with 

 which, however, they have no con- 

 nection), but sometimes only singly; 

 the galls are thick and fleshy, projecting 

 both from the upper and under surface 

 of the leaf, but more so from the under 

 side ; here they are generally green or 

 whitish-green and pubescent, above they 

 are bright red. Only one larva lives in 

 a gall, eating the fleshy walls to a mere 

 shell, when it bites a hole through and 

 falls to the ground, where it pupates in 

 a thick brown cocoon. The sawfly ap- 

 pears in May and September, being 

 double - brooded. Nematus gallicola, 

 Westwood. (Fig. 48.) 



The galls of this species occur com- 

 monly on Salic fra(/llis, L. ; those on 

 S. Caprea, which are similar, but not so Nematus <jalUcola. 



Nt>J 



/ 



Fig. 48. 



