Aphilotrix Sieboldi. o^^ 



the apex of the gall to its base. The tissue of the 

 gall penetrates deeply into the wood of the oak and 

 the smaller stems often die in consequence of this 

 encroachment. (Fig. 6.) 



Rearing the flies. The fly is very easy to rear if the 

 mature galls are collected in the autumn and kept 

 through the winter in a cool place. Next spring, at 

 the end of April or beginning of May, the flies begin to 

 leave the galls. 



Fly. Size 4-5 mm. almost uniformly reddish brown ; 

 the front of the thorax is marked by some fine black 

 lines, the metathorax is somewhat darker. Legs 

 uniformly reddish brown. The whole thorax very 

 hairy. Antennae dark, pale at the base. The fly is 

 very like Aphilotrix radicis but rather lighter in colour. 



Experimental breeding. It is not difficult to watch 

 the fly while ovipositing. It behaves like Aphilotrix 

 radicis, and the buds are similarly pricked, the fly 

 pushing its ovipositor into the base of the bud-axis. 

 The eggs, however, are usually placed in the area of 

 the rudimentary leaves, and galls extremely like those 

 of Andricus nodidi are formed in the stalks and veins 

 of the leaf These have hitherto been described as 

 Andricus testaceipcs. To make sure, and to avoid con- 

 fusion with the Andricus noduli galls, I have for several 

 years made experiments in breeding, invariably keeping 

 the little oak trees under strict control in a room ; 

 but I have always obtained the same galls, resembling 

 the galls of Andricus noduli. 



[The red barnacle gall is biennial, living about fourteen months, and 

 is found on Quercus sessiliflora and Q. pedunculata. 



D 2 



