38 Observations on Cynipidae. 



off, presenting then quite a different appearance, and 

 disclosing the base of the gall sunk in the bark. It is 

 surrounded by a sharp somewhat raised rim which 

 bears on its inner side a row of uniformly pierced 

 punctures. These little openings belong to an earlier 

 period of growth ; and through them passed the 

 vascular bundles that nourished the upper sappy half 

 of the gall. Subsequently the fly gnaws the hole by 

 which it emerges in the centre of the base. (Fig. 7.) 

 The method of rearing and time of appearance are 

 the same as in the other species of Aphilotrix. 



Fly. Size 4 mm., the whole insect dark, of a brownish 

 black colour. Margins of the orbits, base of the 

 antennae, ventral keel and legs bright reddish brown ; 

 apex of femora paler as a rule. Thorax dull, covered 

 with silky hairs. 



Experimental breeding. These flies are easy to 

 rear. Soon after they leave the galls they begin to 

 prick the buds, giving a preference to those buds 

 which have already begun to shoot. They push the 

 ovipositor so deeply into the bud that the eggs are 

 deposited on the base of the leaf germs. It might 

 naturally be supposed that from their great resemblance 

 to the two previous species a similar gall would be 

 formed, and at first I expected to find a gall like 

 Aphilotrix Sieboldi, but the experiments which I made 

 in 1877-1879 satisfactorily cleared the matter up. 

 Between May 6 and 8, 1877, twenty buds on a little 

 oak tree placed in a room were pricked by Aphilotrix 

 corticis. When in June the oak was in full leaf, 

 I noticed here and there on a leafstalk, or in the axil 



