ot BRITISH OAK GALLS. 
Colours.—Pale green, dark green, brown. 
Average dimensions of a mature specimen. — Height, 
2mm.; length, 1] mm.; girth, 3 mm. 
May be sought during the months of April (late), May, and 
-June. 
Growth is complete by the end of May. 
The typical condition of the gall is unilocular and unilarval. 
The larva pupates in the gall. The imago emerges during 
June. 
Alternate agamous generation: Aphilothrix callidoma, 
Hartig. 
This gall does not appear to be very widely 
distributed throughout Britain, or it may be, that by 
reason of the inconspicuous habitat, as well as its 
small size, it has been overlooked, or confused with 
that of A. ramuli. 
The imagines of callidoma apparently prefer to 
oviposit in catkin buds situated high up in the 
tree, where, without the aid of a pruner, they are 
unattainable. I have only once found them within ten 
feet of the ground. Upon the same tree, with field- 
glasses, numerous others could be seen twenty and 
thirty feet higher up. 
“he gall is placed on the stalk of the male catkin ; 
at its base two shallow impressions may be recognised 
which are derived from the sutures of the anthers 
from which the gall sprang. The galls are often 
placed so closely together that they appear to form 
one woolly mass” (‘ Alternating Generations,’ p. 54). 
The affected catkins are considerably shortened and 
seldom project beyond the bud, while others growing 
from the same stem attain normal dimensions. 
The shape of the larval chamber is oval; the 
diameter of its long axis is about 2mm. It is rounded 
at the base and apex; from the former spring a few 
long white hairs which are three or four times longer 
than the gall. The gall grows quickly, reaches 
maturity in about twenty days, and then falls to the 
ground. 
It may be distinguished from A. ramuli because it 
