272 



COCOTJS. 



my house, and which had produced the finest crops of grapes 

 for years past, was suddenly overspread on all the woofly 

 branches with large lumps of a white fibrous substance, 

 resembling 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 encumbrance. It remained aD. the 

 summer, stni increasing, and loaded the woody and bearing 

 branches to a vast degree. I often pulled off great quan- 

 tities by handfuls ; but it was so slimy and tenacious that it 

 could by no means be cleared. The grapes never fiUed to 

 their natural perfection, but turned watery and vapid. 

 Upon perusing the works afterwards of M. de Beaumur, 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 sides 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 de- 

 stroy 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 con- 

 veyed 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 Selbome, no longer ago 

 than August the 1st, 1785. 



At 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. 



