The Natural History of Se I borne 359 



bling spiders' webs, or rather raw cotton. It was of a very 

 clammy quality, sticking fast to everything that touched it, 

 and capable of being spun into long threads. At first I 

 suspected it to be the product of spiders, but could find none. 

 Nothing was to be seen connected with it but many brown 

 oval husky shells, which by no means looked like insects but 

 rather resembled bits of the dry bark of the vine. The tree 

 had a plentiful crop of grapes set, when this pest appeared 

 upon it ; but the fruit was manifestly injured by this foul 

 mcumbrance. It remained all the summer, still increasing, 

 and loaded the woody and bearing branches to a vast degree. 

 I often pulled off great quantities by handfuls ; but it was so 

 slimy and tenacious that it could by no means be cleared. 

 The grapes never filled to their natural perfection, but turned 

 watery and vapid. Upon perusing the works afterwards of 

 M. de Reaumur, I found this matter perfectly described and 

 accounted for. Those husky shells which I had observed, 

 were no other than the female coccus, from whose side this 

 cotton-like substance exudes, and serves as a covering and 

 security for their eggs." 



To this account I think proper to add, that, though the 

 female cocci are stationary, and seldom remove from the place 

 to which they stick, yet the male is a winged insect ; and that 

 the black dust which I saw was undoubtedly the excrement of 

 the females, which is eaten by ants as well as flies. Though 

 the utmost severity of our winter did not destroy these insects, 

 yet the attention of the gardener in a summer or two has 

 entirely relieved my vine from this filthy annoyance. 



As we have remarked above that insects are often conveyed 

 from one country to another in a very unaccountable manner, 

 I shall here mention an emigration of small aphides, which 

 was observed in the village of Selborne no longer ago than 

 August the first, 1785. 



About three o'clock in the afternoon of that day, which 

 was very hot, the people of this village were surprised by a 

 shower of aphides, or smother-flies, which fell in these parts. 

 Those that were walking in the street at that juncture found 



