388 
GALL INSECT. 
There is hardly a plant but what is pierced by 
some species of this genus, and which produces 
some of these nuts, as they are termed, of all sizes 
and colours. The rose, among other plants, has its 
gall, which makes a very singular appearance, re- 
sembling a quantity of branched moss, in the centre 
of which is included the young maggot. Some 
trees have their leaves entirely encrusted with these 
excrescences; particularly the willow, whose leaves 
are sometimes completely covered with them, occa- 
sioned by a small cynips ( C . viminalis Linn.) which 
lies securely imbedded during the winter in one of 
the tumours on the surface of a fallen leaf. 
