BRITISH GALLS. 



501 



tiny ichneumon flies of the most brilliant colors ; and in the Brit- 

 ish Museum there is an excellent example of a chrysalis, which 

 has been filled by a single ichneumon fly, of such a size that the 

 little chrysalis from which it was taken seems scarcely capable of 

 holding it and its cocoon. 



We now pass to a remarkable series of insects belonging to the 

 same order as the ichneumons, but parasitic upon vegetables and 

 not on animals. Their scientific name is Cynipidm, and they are 

 popularly known as GtALL Flies, because they cause those singu- 

 lar excrescences which are so familiar to us under the name of 

 Grails. This group comprises a vast number of species, all of 

 which have a strong family resemblance, though they greatly dif- 

 fer from each other in size, form, and color. 



British Galls. 



Leaf Galls of Oak. Bedeguar of Rose. 



Cynipa i^ollari (slightly magnified). 

 Oak Apple. 



Galls of Cynipa Eollari, 

 Currant Galls of Oak. 



In the accompanying illustration are given several examples 

 of British Galls, most of which are tolerably common in this coun- 

 try, and some of which can be found in plenty. 



