130 BRITISH OAK GALLS. 



Parasites, Nos. 37, 44, 94, 147, 151, 154, 166, 180. Inquilines 

 Nos. 127, 128, 130, 136, 138. 



Alternate agamic generation : Neuroterus lenticularis, 

 Oliver. 



The galls wliicli develop on catkins are generally 

 suffused with pink, or spotted or striped with red ; 

 those on leaves are mostly a rich translucent green. 



They are very soft and contain an abundance of a 

 whitish, tasteless fluid. 



Xo name more appropriate than that of " currant," 

 could have l^een bestowed upon this gall when growing 

 on a catkin peduncle. AYhen on the under-surface of a 

 leaf, a portion of the gall becomes contexturate with 

 the leaf tissues, the attached portion being marked 

 by a pronounced convexity on the upper surface of the 

 leaf, where it is mostly of a red colour. 



The size of those on leaves, is generally about one- 

 fourth more than that of those on catkins. 



Rapid development of the imagines is necessitated 

 by the soft, succulent, and perishable nature of the 

 galls, the entire metamorphosis occupying less than 

 fourteen days. 



This gall is extraordinarily abundant in some years 

 on both catkins and leaves; twigs and small boughs 

 are frequently weighed down with them. Quercus 

 sessilijlora often yields finer specimens, both as regards 

 size, and numerical abundance, than the other species 

 of oak. 



It is the commonest of the globular galls, and, but 

 for the restraining action of numerous ^^arasites, and 

 indirectly of inquilines, many oak trees would have no 

 acorns. 



The gall consists of a very sappy and soft cellular 

 tissue. The larva occupies the centre, eating a large 

 spherical cavity. 



As soon as the imago has escaped, the structure 

 shrivels and decays ; when, however, parasites or inqui- 

 lines are in possession it retains the globular form, 



