72 



BRITISH OAK GALLS. 



Concerning Inquilines from this gall, Cameron says : 

 " Sj/uergus apicalis and Geroptres arator are supposed 

 to be reared from the galls of testaceipes, but they 

 really may have been from those of noduli, the petiole 

 galls of which may have been mistaken for those of 

 testaceipes'' ('Brit. Phyto. Hymen.,' vol. iv, p. 87). 



Considerable doubt seems to exist in the minds of 

 some authors as to whether this species is, or is not, 

 the same as Andricus noduli. The habits of both 

 species are much alike ; the galls of each are the same 

 in size and shape and develop in stem and petiole 

 alike, Andricus testaceipes alone, apparently, on the 

 veins of the leaf. 



According to Adler the imagines cannot be distin- 



FiG. 6. — Galls caused by Andricus testaceipes, on petiole and mid-rib of 

 leaf of Q. sessilijiora. dele, ad nat. E.G. 



guished Avith certainty from each other, their time of 

 emergence is identical, and they oviposit in the same 

 manner. Mayr conjectured as to whether petiolar 

 galls containing a larva of Andricus iwduli were 

 originally produced by A. testaceipes, and A. nodnli 

 has only introduced its eggs, or whether the galls are 

 primarily produced by A. noduli alone. Although he 

 gathered hundreds of these galls in the months of 

 August and September he could not solve the 

 problem. 



Adler's experiments show that the imagines from 

 the galls in leaf- veins and petioles, known as those of 

 Andricus testaceipes, lay their eggs in shoots above 

 ground and produce ApUilothrix Sieholdi galls, which, 

 although gregarious, are unilocular ; and the imagines 



