388 INSECT ARCHITECTURE. 



selects the catkin in preference, by the same instinct 

 that the oak-apple gall-fly, as we have seen, some- 

 times 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 Entertaining Knowledge (Vegetable 

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

 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, there was no caterpillar to be seen, 

 the centre being occupied with a roundish, brown- 

 coloured, woody substance, similar to some excres- 

 cences made by gall-insects (Cynips). Had we been 

 aware of its real nature, we should have put it imme- 

 diately under a glass or in a box, till the contained 

 insect had developed itself; but instead of this, we 

 opened the ball, where we found a small yellowish 

 grub coiled up, and feeding on the exuding juices of 

 the tree. As we could not replace the grub in its 

 cell, part of the walls of which we had unfortunately 

 broken, we put it in a small pasteboard box with a 

 fresh shoot of hawthorn, expecting that it might con- 

 struct 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 considerable 

 portion of its nourishment, both from the part of the 



