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 grow- 

 ing 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 a needle 

 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 drill, 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 dif- 

 ficult to get them by plucking the green apples 



