102 BRITISH OAK GALLS. 



form. The galls occur in groups and in large num- 

 bers on the under-surface of the leaf attached to the 

 mid-rib and the lateral offshoots, in parallel rows, 

 and numbering as many as sixty on a leaf. Each 

 gall is complete and distinct from those near it, and 

 is held in its position by an extremely short and 

 delicate peduncle, so slender that the gall is easily 

 detached. During the month of September they appear 

 as if by magic. The growth is rapid and the first 

 stage is completed very speedily. During October the 

 peduncle slirivels, and the galls fall to the ground. A 

 few will persist until early in November if climatic 

 conditions are favourable. I have found specimens as 

 late as the 12tli of the month. 



Rearing the imagines is a difficult matter. The 

 larvse are but partly grown when the galls fall, and 

 they do not pupate until the early autumn of the 

 following year. Some emerge during the months of 

 December and January, most of the remainder not 

 until May and Juue following ; while a few delay their 

 appearance for six or even twelve months longer. 



The best place to search for these galls is amongst 

 the leaves of stunted oak-bushes on hedge banks that 

 have a northern as23ect ; and in well wooded districts 

 they may be found in great profusion. 



Cynips KoUari, Haiti o. 

 (Plates XXXV to XXXJX.) 



Oyni]js KoUari, Mayr, Sehenck., Newmau, Fitch, Stratoii, 

 Walker; C.lkjnicola, Marshall, Stainton, Parfitt ; C. qiiercvs petioli, 

 Quercus fermiiiaUs, WestAvood ; C. tinctoria, Volleiihoveu. 



English names of gall.— "The Devonshire Gall," "The Oak 

 Marble," " The Oak Nut." " The Marble Gall." 



Position of gall.^Oii twigs and on branches. 



Manner of growth. — Single, solitary, gregarious, coalescent, 

 glabrous, spherical. 



Colours. — Pale green, golden yellow, emerald green, dark green, 

 brownish-yellow, reddish-brown. 



Average dimensions of a mature specimen. — 65nnn. 



