ANDRICUS GLANDULA. 61 
Colours.—Pale green, green, pale brown. 
Average dimensions of a mature specimen. —Height, 
6 mm.; girth (at base), 12 mm. 
May be sought during the months of July to September. 
Growth is complete by the end of September. 
The typical condition of the gall is bilocular, but unilarval. 
The larva pupates in the gall. The imago emerges during the 
following spring. 
Inquiline, No. 1386. 
This dainty little gall may be easily distinguished 
from all other British oak galls by the profusion of 
long white, silky, and glossy recurved hairs with 
which it is almost covered, the exposed portion being 
the papilla. 
It develops from an axillary bud on young twigs; 
very rarely on wood of more than two years’ 
growth. 
As soon as it bursts from the bud it is distinctly 
noticeable owing to the silky-whiteness of the long 
hairs which are arranged like thatching (without the 
rods and spars), on a circular hay-stack or wheat- 
stack, the little papilla standing erect in the centre, 
hence the English name of “thatched gall” which I 
propose for it. 
As growth proceeds the hairs remain adpressed to 
the gall, the texture of which becomes woody. 
The lower portion of the gall is expanded into a 
turban-like base having occasionally a number of leaf- 
scales adherent beneath it; these ultimately fall off and 
expose a somewhat stout process or peduncle by which 
the gall is held to the twig. In some examples this 
basal portion is much more fully developed than in 
others. 
The shape of the gall when mature is that of a 
truncated cone, bearing upon its summit a very small 
mastoid growth, known as the papilla, which is subject 
to much variation in size. Itisa pale greenish-yellow 
colour and is destitute of hairs in all stages of its 
development. . 
During the winter the gall falls to the ground, or it 
