GALL-FLIES. 333 



saw it, we imagined that the twig was beset with some 

 species of the lanigerous aphides, similar to what is vulgarly 

 called the American or white blight {aphis lanatd) ; bnt on 

 closer examination we discarded this notion. The twig 

 was indeed thickly beset with a white downy, or rather 

 woolly, substance around the stem at the origin of the leaves, 

 which did not appear to be affected in their growth, being 

 well formed, healthy, and luxuriant. We could not doubt 

 that the woolly substance was caused by some insect ; but 

 though we cut ont a portion of it, we conld not detect any 

 egg or grub, and we therefore threw the branch into a 

 drawer, intending to keep it as a specimen, whose history 

 we might complete at some subsequent period. 



A few weeks afterwards, on opening this drawer, we 

 were surprised to see a brood of several dozens of a species 

 of gall-fly (Cynips), similar in form and size to that whose 

 eggs cause the bedeguar of the rose, and differing only in 

 being of a lighter colour, tending to a yellowish brown. 

 We have since met with a figure and description of this gall 

 in Swammerdam. We may remark that the above is not 



Semi-Gall of the Hawthorn, produced by Cecidomyia ? drawn from a specimen. 



the first instance which has occurred in our researches, of 

 gall insects outliving the withering of the branch or leaf 

 from which they obtain their nourishment. 



The woolly substance on the branch of the oak which we 

 have described was similarly constituted with the bedegnar 



