388 IXSECT ARCHITECTURE. 



which selects the catkin in preference, by the same 

 instinct that the oak-apple orall-fly, as we have seen, 

 sometimes deposits its eggs in the bark of the oak 

 near the root. 



The gall of the oak, which forms an important 

 dye-stuff, and is used in making writing-ink, is also 

 produced by a Cynips, and has been described in the 

 Library of Enteriaining Knowledge, (Vegetable 

 Substances, p. 16.) The employment of the Cymps 

 psenes for ripening figs is described in the same 

 volume, p. 244. 



Gall of a Hawthorn Weevil. 



In May, 1829, we found on a hawthorn at Lee, in 

 Kent, the leaves at the extremity of a branch neatly 

 folded up in a bundle, but not quite so closely as is 

 usual in the case of leaf-rolling caterpillars. On 

 opening them up, there was no caterpillar to be 

 seen, the centre being occupied with a roundish, 

 brown-coloured, woody substance, similar to some 

 excrescences made by gall insects {Cynips). Had 

 we been aware of its real nature, we should have put 

 it immediately under a glass or in a box, till the con- 

 tained insect had developed itself; but instead of this, 

 we opened the ball, where we found a small yellow- 

 ish grub coiled up, and feeding on the exuding 

 juices of the tree. As we could not replace the grul3 

 in its cell, part of the walls of which we had unfor- 

 tunately broken, we put it in a small pasteboard box 

 with a fresh shoot of hawthorn, expecting that it 

 might construct a fresh cell. This, however, it was 

 probably incompetent to perform: it did not at least 

 make the attempt, and neither did it seem to feed on 

 the fresh branch, keeping in preference to the ruins 

 of its former cell. To our great surprise, although 

 it was thus exposed to the air, and deprived of a con- 

 siderable portion of its nourishment, both from the 



