GALL MITES. 



335 



CASE opening to tke interior from the under side of the leaf, while the 

 latter has none, but is a closed sack. 



Leaf of American vine bearings trumpet g'alls (work of a 

 Cecidorayia). Copied from Mr. Riley's figure. 



Section of ditto, drawn ironi 

 description. 



But to return to the history of the discovery of the makers of 

 these gails : Whether Reaumur saw them or not, at least no one 

 else did for about too years after. About 1832 and 1834, how- 

 ever, the publication of M. Duges' valuable papers on the classifi- 

 cation of the Acaridse to which we have already had so often to 

 refer, gave an impulse to their study, which led to fresh discoveries; 

 and M. Turpin observed in the nail-galls of the lime-leaf, a quan- 

 tity of very minute semi-transparent fleshy mites of a new and 

 hitherto unknown form — a narrow creature with two pairs of small 

 legs at its head, and some kind of sucker apparatus at its tail, on 

 which it rests and raises itself, swaying about its body. He 

 regarded it as a species of Sarcoptes. 



The different views enunciated on each successive discovery by 



