Aphilotrix callidoma, 53 



and left on damp sand until they begin to get brown, 

 which is a sign that the larva is full grown ; they should 

 then be kept in a cool place or in the open air through 

 the winter. Some of the flies appear during the next 

 spring, but others lie dormant until the second year. 

 It is probable that galls maturing early hatch out in the 

 first year, and that those maturing late do so in the 

 second year. It is particularly to be remarked that the 

 majority of the galls are beset with parasites, and this is 

 probably the reason why the fly has not been identified 

 before. 



Fly. 4 mm. long; reddish yellow ; antennae, sutures 

 of the thorax, and margins of scutellum, black ; the back 

 of the abdomen dark brown ; head and thorax sparsely 

 haired ; legs yellowish brown, trochanters only black ; 

 posterior tibiae brown. 



Experimental breeding. The flies emerge in April 

 and seek the male catkin buds in which to lay their 

 eggs. For this reason I have only been able to watch 

 them ovipositing in the open air, or on branches cut 

 off for the purpose. The fly lays its ^^g upon and 

 between the anthers, while they are enclosed in the 

 bud ; and there are often a great many laid in the same 

 bud. In April, 1878, I marked a number of buds pricked 

 in the open air. At the time when most buds were more 

 or less developed those which had been pricked were 

 remarkably backward, only a few flowering catkins 

 projecting from them. On further examination it was 

 seen that the anthers were quite distorted by small 

 closely set galls. This gall, which I am about to 

 describe, was that of Andn'cus cirratus. 



