CHAPTER XXVI. 



PARASITIC NESTS— (CONCLUDED.) 



The Oak-tree, and its aptitude for nourishing Galls— Compound Galls, or 

 one Gall within another — The Sensitive Gall of Carolina — The fungus of 

 wine-vaults — Galls and the Insects which caused them — Colours of Galls — 

 Whence derived — The Galls of various trees and plants — The Cynips parasites 

 upon an insect — Galls produced by other insects — Mr. Eemiie's account of the 

 Beetix Gall of the Hawthorn— The Beetle Gall of the Thistle— Dipteeous 

 Gall-makeks— Leaf- Miners and Galls — Size of the larvse of Leaf-Miners— The 

 perfect insect and their beauty — Method of displaying the insect — Social Leap- 

 MiNEES — DiFTEROVS Leaf-Mimebs — Animal Galls — The Cbigoe and its habits 

 — Its curious egg-sac — ^Difficulty of extirpating it — The penalty of negligence — 

 The Bbeeze Flies and their habitations — "Wuebles and theii origin — Their 

 influence upon cattle — The Clerits and its ravages among the hives — The 

 Drilus, its remarkable form and the difference between the sexes — The 

 curious habitation which it makes. 



The reader cannot but notice the singular aptitude possessed by 

 the oak-tree for nourishing galls. No part of the tree seems to 

 escape the presence of a gall of some sort, diverting its vital 

 powers into other channels. The tree, however, does not appear 

 to suffer from them, and it is just possible that they may be 

 useful to it. The leaves are studded with galls, and so are their 

 stems. The branches are covered with gaUs of various shapes, 

 sizes, and colours, some bright, smooth, and softly coloured, like 

 ripe finiit, others hard, harsh, spiny, and rough, as if the very 

 essence of the gnarled branches had been concentrated in them. 

 There are galls upon the flowers, galls upon the trunk, and even 

 galls upon the root. 



Some oak-galls may be called compound galls. M. Bosc men- 

 tions a small gaU which is found upon the American oak. It 

 is not larger than a pea, and if shaken is found to contain some 

 hard substance loosely lodged in its interior. When the gall is 

 cut open, a very curious state of things is seen. The walls are 

 very thin, so that in spite of the small dimensions, the cell is 

 larger than that of many cynipidae. Within the cell, no insect 



