66 BK1TI8H OAK GALLS. 



The gall consists of two thin layers, and an inner 

 loose larval chamber. 



The colour of the external layer is clark-3^ellow ; 

 that of the internal layer reddish-brown, the larval 

 chamber more or less yellowish. 



The imago w^hich causes the gall appears to prefer 

 to oviposit among the highest branches of the tree. 



A peculiarity about this gall has been observed, viz. 

 that they fall to the ground after the first frost, 

 retainino- the l)ud-like scales attached to their base. 

 When A. glohuli falls to the ground the scales have 

 either previously dropped off or they are left on the 

 twig. 



A. glohuli has never been observed so high up on the 

 tree as Artdricus clementince^ grows. 



Andricus curvator, Haiti g. 

 (Plates VI, VII.) 



Andricus CKrvator, Mayr, Miiller, Fitch, Adler ; A. ]jerfoliatus, 

 Scheuck; A. dimidiatus, Schleclitdl. ; Cynips cnrvator, Thomson; 

 C. axillaris, Hartig. 



English name of gall. — " The Curved Leaf Gall." 



Position of gall. — On blade, mid- rib, or petiole of leaf. 



Manner of growth. — Glabrous, glossy, single, conglomerated, 

 anastomosing. 



Colours. — Pale green, light brown. 



Average dimensions of a mature specimen. — Length, 

 8 mm. ; breadth, 8 mm. ; girth, 24 mm. 



May be sought during any month of the year. 



Growth is complete by the end of July. 



The typical condition of the gall is bilocular, but unilarval. 



The larva pupates in the gall. The imago emerges during 

 August. 



Parasites and inquilines are given on p. 58. 



Alternate agamous generation: AjihUothrix coIJaris, Hartig. 



This gall is widely distributed throughout Britain. 

 It appears in the form of a swelling of the young- 

 leaves of both species of oak, as plentifully on young 



