122 BRITISH OAK GALLS. 



The usual numl)er of galls on a leaf is 80-100. These 

 figures are, however, greatly exceeded in seasons when 

 such galls are prolific. 



They fall to the ground late in September, and dur- 

 ing October, development continuing very gradually 

 through the winter, and until the imagines emerge in 

 March and April. 



They are extensively eaten by game birds. 



Neuroterus numismatis, Olivier. 

 (Plate XLIX.) 



Cynips numismatis, Olivier; C. quercus-tiara^., Curtis ; Neiiroterus 

 Beaumnri, Hartiy, Schenck, Marshall ; JV". numismatis, Mayr, Adler, 

 Licht., Miiller, Cameron : Spatliegaster vesicatrix, Schltdl., Mayr, 

 Adler, Licht. 



English name of gall. — " The Silk-Button Spangle Gall." 



Position of gall. — On the under- siu-f ace of the leaf. 



Manner of growth. — Gflossy, smooth, hemispherical, gregarious, 

 umbilicate. 



Colours. — Grolden yellow, bright ochre, golden l)rown. 



Average dimensions of a mature specimen. — Height, 

 1-5 mm. ; girth, 9 mm. 



May be sought during the months of August to October. 



Growth is complete by the end oi September. 



The typical condition of the gall is unilocidar and unilarval. 



The larva pupates in the gall. The imago emerges during 

 March and April. 



Parasites, Nos. 13, 89, 40, 41, 72, 76, 163. Inquiline, 

 No. 142. 



Alternate sexual generation : Spathegaster vesicatrix, Schltdl. 



Mayr considers this to be " the most beautiful of 

 all the lenticular galls." 



The entire gall is covered, and also coloured by 

 closely set, smooth, glossy, golden-brown adpressed 

 hairs, and these impart to it a very real appearance of 

 a diminutive silk-covered button. 



The galls are deciduous, falling to the ground in 

 October and November, maturing during the next 



