130 BRITISH OAK GALLS. 
Parasites, Nos. 37, 44, 94, 147,151, 154, 166,180. Inquilines 
Nos. 127, 128, 130, 186, 138. 
Alternate agamic generation: Newroterus lenticularis, 
Oliver. 
The galls which 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. 
No name more appropriate than that of “ currant,” 
could have been bestowed upon this gall when growing 
on a catkin peduncle. When 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 
sessiliflora 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 parasites, 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, 
