118 BRITISH OAK (JALLS. 



In its normal and typical condition there are several 

 distinctive features, (a) Its average diameter (3 mm.) 

 is less, {h) tlie upward curve of its rim is more pro- 

 nounced, (c) the central papilla is not so distinct, ((/) 

 the under-surface is rarely whitish or yellowish, (e) nor 

 is it usually so abundant as X. Jenficitlaris. 



The mode of attachment to the leaf is l^y means of 

 an extremely short and thin peduncle Avhich retains 

 the gall with considerable tenacity until the autumn, 

 when it decays and the gall falls from the leaf. The 

 moisture of the earth allows development to continue 

 gradually until the gall is about double its former 

 thickness. 



Cameron remarks : " The larva does not develop 

 until April, being later in its development than lenti- 

 cularis and niimismatis, the imago not appearing until 

 May " C Brit. Phyto. Hymen.,' vol. iv, p. 134). Adler 

 also says : " Although these galls fall to the ground in 

 October it is only during the month of March [of the 

 following year] that larval development begins ; 

 towards the end of April it becomes a pupa, and the 

 perfect insect appears in May " ('Alternating Genera- 

 tions,' p. 23). 



Some years this gall, in common with the other 

 Neuroterus species, occurs in extraordinary abundance, 

 not only as regards the number of oak leaves bearing 

 galls, but the profusion of the galls on the leaves. 

 The autumn of 1907 was such an occasion. 



Neuroterus Iseviusculus, Schenck. 

 (Plate XLVII.) 



Netiroterns pezizfeformis, Scliltdl. ; N. I^viusculus, Mayr, Adler, 

 Fitch, Schenck, Licht., Cameron ; Sjmthegaster alhi])es, Schenck, 

 Licht.. Mayr, Adler. 



English name of gall. — " The Smooth Spangle Gall." 



Position of gall. — On the under- surface of the leaf. 



Manner of growth. — Glaljrous, glossy, separate, scattered, 

 cupulate. 



