ROSE GALLS. 507 



colored insect, named Cynips rosce, which selects the tender twigs 

 of roses, and deposits its eggs upon them. 



I have now before me quite a collection of these galls, some of 

 which are so variable in shape that they scarcely seem to have 

 been made by the same species of insect. When the Cynips rosse 

 deposits her eggs upon the rose, the effects are rather remarkable. 

 Each egg becomes surrounded with its own cell or gall, and the 

 whole of them become fused into one mass. The exterior of these 

 galls is not smooth, like that of the specimens which have been 

 described, but is covered with long, many-branched hairs, which 

 stand out so thickly that they entirely conceal the form of the 

 gall itself. 



Keaumur, who gave much attention to galls, thought that the 

 hairs were formed by the exudation of sap through little orifices 

 in the growing gall, just as the web of the spider is formed by the 

 exudation of a glutinous liquid from minute pores. This theory, 

 however, is scarcely tenable, because sap has no power of hard- 

 ening into threads when exposed to the air, and, besides, a well- 

 defined vegetable structure is seen in the hairs, which would not 

 be the case if they were merely hardened sap. Moreover, if the 

 hairs were formed in this manner, they could not have the power 

 of throwing out the tiny branchlets with which they are studded, 

 or of ramifying like the bough of a tree, as is often the case with 

 them. 



The number of galls in a single Bedeguar is mostly very great. 

 A specimen of average size, taken at random from the drawer in 

 which the galls are kept, was, when fully clothed, as large as a 

 golden pippin. When the hairy clothing was removed, its size 

 notably diminished, and it was then seen to be composed of a large 

 number of woody tubercles, varying much in size and shape. 

 Their average dimensions, however, are about equal to those of an 

 ordinary pea. The tubercles in question are fused together more 

 or less strongly, some falling off at a slight touch, while others 

 can not be separated without the use of the knife. There are 

 about thirty-five of these wooden knobs. 



On selecting one of the knobs, and examining it, a few very 

 small circular holes are seen, showing that the insects have made 

 their escape from the cells. Indeed, one or two of the insects 

 were found entangled amid the dry and crisp hairs that surround- 

 ed the gall, and which formed a second barrier, which they could 

 not penetrate. When, however, a sharp knife is carefully used. 



