14 BRITISH OAK GALLS. 
case, except that of Fig. 32, both sections have reached 
maturity. Hach section possesses a larval cell. 
Two or three galls of Andricus cwrvator frequently 
grow together, forming but one cavity, with two or 
three larval cells. Or the gall may develop near the 
base of the petiole, and produce a swelling bearing a 
strong resemblance to A. inflator. Neuroterus levius- 
culus affords some interesting variations, a few of 
which are represented in Fig. 14, where they are also 
briefly described. 
VARIATIONS IN Size, Texture, CoLour. 
Sizp: (a) Girth.—The smallest of all known galls 
is that of Neuroterus minutulus, Gir. It is not yet 
recorded for Britain. “It is spherical, 1-2 to 1°5 mm. 
in diameter, thickly covered with short conic-ovate 
tubercles, and of a rusty brown colour” (‘ The Ento- 
mologist,’ vol. x, p. 173). 
To return to British galls. The dimensions attained 
by Aphilothria radicis undoubtedly exceed those of any 
other gall. The largest the author has found was on 
a very old stump, on June 18th, 1902. It measured 
32 cm. at its greatest girth. Had it not been removed 
it would have increased considerably by the end of 
August, at which time it would have attained maturity. 
C. Kollari develops into the largest unilocular gall ; 
specimens measuring 75 mm. in girth are not un- 
common (See Plate XXXVI, fig. 1). The cherry-gall 
occasionally attains 63 mm. in girth. 
(b) Length—The genus of Andricus furnishes at 
least nine examples of galls whose external measure- 
ments do not exceed 2 mm. in length. Two of these 
seldom attain that length. Both A. nudus and 
A, pilosus are normally not more than 1:5 mm. long. 
The latter species appears to be larger, but that is due 
to the hairlets with which it is covered. 
The stalked-spindle gall, caused by Aphilothrix calli- 
doma, far surpasses all oak galls in its length. Specimens 
