Nematus bellas. 



These hairy pea-shaped galls, which are firmly attached to 

 the undersides of the leaves of Salix capixa, are so like those 

 caused by Nematus salicis-cinerecB on "the smooth leaves of 

 some other willovirs that it is open to doubt whether both are 

 not produced by the same species of saw-fly. Cameron says 

 ("British Phytophagous Hymenoptera," vol. ii., p. 201): "An 

 examination of long series of both shows that they approximate 

 very closely in all respects, both showing considerable variation 

 in colour and size ; there does not seem either to be any tangible 

 difference in the structure of the saws, and I am equally unable 

 to point out any difference between their larvae. There is no 

 difference in the form of the galls, for although the gall of 

 belliis is usually more irregular in .shape than that of salicics- 

 inerece, still, the galls of the latter vary also. The fact of the 

 bellus galls being hairy is clearly owing to the willow leaves 

 being hairy." The shape of these galls varies. They are mostly 

 globular, but some assume an ovid shape. When two coalesce, 

 the outline becomes irregularly oval. The interior is smooth 

 and devoid of hairs. The walls are thin but tough. The fras 

 is retained within the gall. They occur singly and in twos 

 and threes ; the presence of five, as shown on one leaf in the 

 illustration, is very unusual. The colour is greenish yellow, 

 with a few purple spots upon small projections ; the outer 

 surface is thickly clothed with long greyish hairs. The larva 

 can walk well and rapidly upon a level surface. When fully 

 fed it eats its way out, and soon after the deserted structure 

 shrivels and turns a chocolate-brown. 



The illustration is of specimens gathered at Hastings by 

 the author. 



