390 INSECT ARCHITECTURE. 



of the roots of cabbages, and the knob-like galls on 

 turnips, called in some places the anbury. We have 

 found them also infesting the roots of the holyhock 

 (Alcea rosea). They are evidently beetles of an allied 

 genus which form the woody galls sometimes met 

 with on the leaves of the guelder-rose ( Viburnum), 

 the lime-tree (Tilia Europcea), and the beech (Fagus 

 sylvatica). 



There are also some two-winged flies which pro- 

 duce woody galls on various plants, such as the 

 thistle-fly (Tephritis cardui, Latr.) The grubs of 

 this pretty fly produce on the leaf-stalks of thistles 

 an oblong woody knob. On the common white 

 briony (Bryonica dioica) of our hedges may be found 

 a very pretty fly of this genus, of a yellowish brown 

 colour, with pellucid wings, waved much like those 

 of the thistle-fly with yellowish brown. This fly lays 

 its eggs near a joint of the stem, and the grubs live 

 upon°its substance. The joint swells out into an 

 oval form furrowed in several places, and the fly is 

 subsequently disclosed. In its perfect state it feeds 

 on the blossom of the briony* Flies of another 

 minute family, the gall-gnats (Cecidomyim, Latr.), 

 pass the first stage of their existence in the small 

 globular cottony galls which abound on germander 

 speedwell ( Veronica chumcrdrys), wild-thyme (Thy- 

 mus serpyllum), and ground-ivy (Glechoma hede- 

 racea). The latter is by no means uncommon, and 

 may be readily recognised. 



Certain species of plant-lice (Aphides), whose 

 complete history would require a volume, produce 

 excrescences upon plants which may with some pro- 

 priety be termed galls, or semi-galls. Some of these 

 are without any aperture, whilst others are in form 

 of an inflated vesicle, with a narrow opening on the 

 under side of a leaf, and expanding (for the most 

 * J. U. 



