DIPTERA. 



343 



October. It is quite possible there are several broods, as I have 

 hatched them out in confinement in Northumberland from the begin- 

 ning of July to the end of October ; and as the larvae pupate within 

 the galls, artificial hatching is very simple, provided we see that they 

 are in the pupal stage prior to being placed in a glass-covered box. 

 By stupefying the insects with chloroform we can very easily examine 

 them with the inch objective. 



Male. The body and antenna? are darkish-brown colour ; antennae 

 15- to 16-jointed, as long as the body. The thorax slightly reddish; 

 abdomen yellowish - brown ; wings covered by darkish hairs. The 



Fig. 313. Leaves o/ Salix viminalis rolled by Cecidomyia marginemtorquens. 



legs are of a lightish colour, and slightly tinged with red at the joints. 

 Length 1 to H mm. (Fig. 3U.) 



Female. The body is of a dark - grey colour, with rather com- 

 paratively longish halteres. Face light - grey ; the wings are clear, 

 but hairy, more especially at the edges. Eyes large, deep velvety- 

 black. The head and thorax black, with stiffish erect bristles ; 

 abdomen dark -grey above, light-grey beneath. The antennae light- 

 grey, with a darkish tinge throughout. The legs are light in colour; 

 oviduct long and slender. Length 1-2 mm. (Fig. 315.) 



The conspicuous difference between the antennae of the male and 



