HYMENOPTERA SAW-FLIES, ETC. 



183 



PONTANIA PROXIMA, Lep. 



This species was sent by my friend Mr Forgan, Bowood, Wiltshire, 

 in stems of golden willow. No swellings : only indication is small 

 hole in stem. Larva? bore in pith. This hatched May 14, 1902, in 

 confinement. 



Fly. Head, body, and antenna? black. Legs more or less test- 

 aceous. Wings black. Antenna? 7-jointed. Larvce, white body, 

 brown head, J^ inch in length. 



PONTANIA GALLICOLA (Steph.) 



Nematus vallisnerii, Htg. 

 Nematus gallicola (West). 



In almost every country ramble the leaves of Huntingdon willows 

 may be seen covered with the bean-shaped galls caused by N. gallicola. 

 The galls (fig. 171) are 

 always formed on both sides 

 of the leaf. They are of a 

 rosy colour, and therefore 

 contrast with the green leaf. 

 A section of the gall, to- 

 gether with a description of 

 its development, would be 

 interesting. In the centre of 

 the gall we get the paren- 

 chyma of the leaf so en- 

 veloped by the gall that this 

 green substance becomes the 

 food of the larva. 



There are two broods in 

 the year. By collecting the 

 galls fairly early in autumn, 

 before the larva? quit them 

 for pupation, they may be 

 easily hatched out artificially. They quit the galls, and form small 

 leathery cocoons. The flies appear about 9th May in Northumberland. 

 The second brood is said to hatch out in August. 



Fig. 171. Galls o/Pontania gallicola on 

 Huntingdon willow. 



