NATURAL HISTORY OF SELBORNE. 255 



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 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 Selborne no longer ago 

 than August 1st, 1774. 



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 themselves covered with these insects, which settled 

 on the hedges and gardens, blackening all the vegetables 

 where they alighted. My annuals were discoloured with 

 them, and the stalks of a bed of onions were quite coated 

 over for six days after. These armies were then, no doubt, 

 in a state of emigration, and shifting their quarters ; and 

 might have come, as far as we know, from the great hop 

 plantations of Kent or Sussex, the wind being all that 



