110 BRITISH OAK (iALLS. 



The texture of the gall is hard, but the walls are 

 thin ; and the larval chamber verv large. The exterior 

 is rarely suffused with pink or red. This forms one 

 external distinguishing feature from I). cUrisa, which is 

 pink during the greater part of its growth. Both 

 species are about the same size, but dicisa is generally 

 slightly larger. Both, also, frequently have flat, 

 reddish-brown, very small nodules scattered over the 

 exterior. 



This gall was first observed in England about forty 

 years ago, the imagines having been reared by Albert 

 Miiller and recorded in ' Proc. Ento. 8oc. Loncl.,' 1870, 

 xxxiv. 



Although an alternate generation does not appear to 

 be known, the fact that the imago does not normally 

 pass the winter in the gall, would indicate that a sexual, 

 or spring form, may exist. 



Dryophanta disticha, Hartig. 

 (Plate XLI.) 



Cynips disticha, Hartig, Sclmk. : Aphilotlirix disticha, Mayr : 

 Andrio's disticha, Mayr: Dryophanta disticha, Mayr, Cameron. 



English name of gall. — "The Tvro-Cell Gall." 



Position of gall. — On the imcler-surface of the mid-rib and its 

 offshoots. 



Manner of growth. — Single, glabrous, slightly glossy, imique 

 in form. 



Colours. — Yellowish-white, pale yellow, light brown, reddish- 

 Ijrown. 



Average dimensions of a mature specimen. — Height, 

 4 mm. ; length, 6 mm. ; breadth, 4 mm. 



May be sought during the months of July to September. 



Growth is complete l)y the end of August. 



The typical condition of the gall is liilocular but unilarval. 



The larva pupates in the gall. The imago emerges during 

 the autumn. 



Parasites, Nos. 19, 44. 46. 47, 59, 64, 105, 112. 114. 117, 120, 

 150, 151, 154, 180, 183. Inquilines, Nos. 127, 134. 



In some districts this gall is exceedingly rare. 

 Xowhere does it appear to be plentiful. Only very 



