BRITISH GALLS. 483 



being entirely scarlet, while others are white, orange, and red, in 

 various gradations, something like the colour of a nearly ripe 

 peach, or those of a Newtown pippin. Perhaps they bear more 

 resemblance to the apple than to the peach, because their surface 

 is highly polished and shining, much like that of the American 

 apple. 



These galls may be found in profusion upon the oak-leaves, 

 and are most plentiful upon pollard oaks, upon the youngest 

 trees, or upon the oak imderwood that sprouts around a felled 

 trunk. In such cases the leaves are much larger, and fuller of 

 juice than those which spring from adult trees, and the develop- 

 ment of the gall is proportionately increased. Wherever there 

 is a thick growth of oaken underwood, the numberless galls 

 which stud the leaves have a remarkably beautiful effect, pro- 

 vided that the observer lies on the ground, or stoops sufficiently 

 low to perceive the under-surface of the leaves, to which the 

 galls are attached. 



If one of the galls be cut open with a knife, it will be found 

 to consist of a soft, pulpy substance, fuller of juice than an 

 apple, and somewhat resembling the consistence of a hothouse 

 grape. In the very centre of the soft mass the knife will meet 

 with resistance in the shape of a globular cell of hard, woody 

 texture, and in the middle of the cell will be found a tiny 

 grub, perfectly white, very fat, somewhat resembling the grub 

 of the humble bee, and curved so as to fit the globular cell 

 in which it lies. This is the little being for whose benefit 

 the gall was formed, and the little white grub feeds on the 

 juices of the gall, precisely as the larva of the ichneumon fly 

 feeds on the soft portions of the insect in which it temporarily 



On seeing the little creature thus snugly ensconced in the 

 receptacle which serves it at once for board and lodging, a 

 question naturally arises as to the manner in which it was 

 placed there. No aperture is perceptible in the gall, not a hole 

 through which air can reach the enclosed larva, which must, 

 therefore, be capable of existing without more air than can pass 

 through the minute pores of the vegetable substance in which it 

 lies, or must be able to respire by means of the oxygen which is 

 given out by living plants. 



The question, indeed, is very like the well-known query as to 



Il2 



