SPANGLE-GALLS. 
307 
species, while others think that the galls are the production of 
the same insect which forms the leaf-gall, the punctures being 
made in the stalk of the catkin and not in the nervure of the 
leaf. 
That this supposition may be correct is evident from the fact 
that the same insect which forms the oak-apples does also 
deposit its eggs in the root of the same tree, causing large 
excrescences to spring therefrom, each excrescence being filled 
with insects. I have often obtained these root-galls, several of 
which are now before me, some having been cut open, in order 
to show the numerous cells with which they are filled, and others 
left untouched, in order to exhibit the form of the exterior. 
Being nourished by the juices of the root, they partake of the 
sombre hues which characterise the part of the tree from which 
they spring, and do not display any of the colours which are 
seen on the oak-apples which spring from the twigs. 
There are, however, distinct species of gall insects which 
pierce the roots of the oak-tree. One of them is termed Cynips 
aptera , and makes a pear-shaped gall about one-third of an inch 
in diameter. Each gall contains a single insect, and a number 
of the galls are often found attached by their narrow end to the 
root-twigs of the tree, something like a bunch of nuts on a 
I branch. There is another insect which is termed Cynips quercns - 
radicis , which forms a many-chambered gall of enormous size, 
containing a small army of insects. Mr. Westwood mentions 
that one of these galls in his possession was five inches long, 
one inch and a quarter wide, and produced eleven hundred 
insects, so that the entire number was probably fourteen or 
fifteen hundred. 
No one who is accustomed to notice the objects which imme- 
diately surround him can have failed to observe the curious 
little galls which stud the leaves of several trees, and which 
are appropriately called Spangle-galls, because they are as 
circular, and nearly as flat, as metallic spangles. 
These objects had been observed for many years, but no one 
knew precisely whether their growth was due to animal or vege- 
