34 IN THE ACADIAN LAND.
in the oak apple we have in the grubs, the young of a small fly. The female has a hollow drill connected with the eggs in her body. She is a gall-fly, and the proper name of these apples is gall. When the season comes around the gall-fly finds an oak-tree, and in a tiny growing leaf or twig she drills a hole and shoots into it her eggs, three or four in number, and then repeats the operation. Now we may use aneedle and prick a bud or leaf, and do what we will in that way there is only a slight scar left ; but the work of that chill, finer than a cambric needle, has changed the mode of growth — apparently poisoned the delicate cell-structure. Quickly following the wound the swelling begins, and the result of it is this globular shell, with kernel at the centre of very rich food for grubs, much more nutritious than the leaves of the oak, and there is nothing for them to do but eat and grow fat. This is followed up with occasional moulting of the old skin, till another stage is reached, when they become pupae, do themselves up in tiny cases, and wait for wings and other organs like their parents. When this is done they gnaw out of their prison, and join their kind in the outside world. The fly is about one-quarter of an inch in length. It is not difficult to get them by plucking the green apples