OAK-APPLES . 
3 QI 
still in the larval state, burrows into the earth, and there 
changes into the pupal and perfect forms. 
To the unassisted eye, the insect which forms the leaf-gall 
presents no especial attraction, as it is simply, to all appearance, 
a little black fly. When placed under the microscope, however, 
it soon proves to be a really beautiful creature, though not pos- 
sessing the brilliant and gem-like hues which distinguish many 
of its relatives. The body still retains its blackness, but has a 
soft tint on account of the white and shining hairs with which 
it is thickly studded. The eyes are large, stand boldly from 
the head, and the many lenses of which these organs are com- 
posed are so boldly defined, that even in so small an insect 
they can be distinguished with a very low power of the micro- 
scope. Indeed, the inch-and-a-half object glass is quite 
powerful enough to define them, while the half-inch glass makes 
them look like the pits in a lady’s thimble. 
The chief beauty of the insect, however, lies in the wings, 
which are very large in proportion to the size of the owner, are 
traversed by a few, but strong nervures, and glow with a 
changeful radiant lustre, like mother-of-pearl illuminated with 
living light. In order to see these wings properly, the insect 
should be laid on some black substance, and the light concen- 
trated upon them by the various means which a microscopist 
can always employ. 
The oak is a tree that seems to be especially loved by gall- 
insects, which deposit their eggs in its leaves, its twigs, its 
flowers, and even in its roots. One of the most familiar 
examples of oak galls is that which is called the oak-apple, and 
which is produced by a species of insect called Cynips termi- 
nals. Although the insect is not of very great size, the gall 
which it produces is sometimes enormous, being as large as a 
common golden pippin or nonpareil apple, and therefore very 
conspicuous upon the tree. It is coloured in the same manner 
as the cherry-gall, but seldom so brilliantly, and the exterior is 
not so smooth and polished. 
