SMOTHER'FLY. 251 



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 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. * 

 Those that were walking in the street at that juncture, found 

 themselves covered with these insects, which settled also 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 day in the easterly quarter. 

 They were observed, at the same time, in great clouds about 

 Farnham, and all along the vale from Farnham to Alton, f 



LETTER XCVIII. 



TO THE HON. DAINES HARRINGTON. 



DEAR SIR, When I happen to visit a family where gold 

 and silver fishes J are kept in a glass bowl, I am always pleased 



* There are several species of these troublesome, although minute, 

 animals ; the loftiest tree is as liable to their attacks as the most humble 

 plant. Their numbers are incalculably great. They prefer the young and 

 tender shoots, and frequently insinuate themselves into the very heart of 

 the plants, where they commit much havoc. Some feed indiscriminately 

 on every kind of plant, while others confine their ravages to one species 

 of plant only. The aphis of the rose tree too frequently despoil this 

 delightful flower. The aphides afford a very striking deviation from the 

 general laws of nature, one impregnation of the female is sufficient for 

 nine generations. ED. 



f For various methods by which several insects shift their quarters, 

 see Derham's Physico - Theology. 



| The gold and silver fishes are but one species, the cyprinus auratus 

 of Linnaeus. The young fry, when first produced, are perfectly black, 

 but they afterwards change to white, and then to gold colour ; the latter 

 colours appear first about the tail, and extend upwards. The smallest 

 fish are the most beautiful, being of a fine orange red, appearing as if 

 sprinkled over with gold dust ; some are silvery white, and others white, 



