258 APHID^ — PLANT- LICE. 



Tisickes, and for others that are ulcered in the intestines, as 

 is confirmed by the Histories of Portufjall.^'^ 



The Aphides, like many other insects, sometimes migrate 

 in clouds ; and among other instances on record of these 

 migrations, Mr. White informs us that about three o'clock 

 in the afternoon of the first of August, 1785, the people of 

 the village of Selborne were surprised by a shower of 

 Aphides "which fell in those parts. Persons who walked in 

 the street at this time found themselves covered with them, 

 and they settled in such numbers in the gardens and on the 

 hedges as to blacken every leaf. Mr. White's annuals were 

 thus all discolored with them, and the stalks of a bed of 

 onions were quite coated over for six days afterward. These 

 swarms, he remarks, were then no doubt in a state of emi- 

 gration, and might have come from the great hop-plantations 

 of Kent and Sussex, the wind being all that day in the east. 

 They were observed at the same time in great clouds about 

 Farnham, and all along the vale from Farnham to Alton. ^ 

 A similar emigration of these insects Mr. Kirby once wit- 

 nessed, to his great annoyance, when traveling later in the 

 year in the Isle of Ely. The air was so full of them, that 

 they were incessantly flying into his eyes and nostrils, and 

 his clothes were covered by them; and in 1814, in the au- 

 tumn, the Aphides were so abundant for a few days in the 

 vicinity of Ipswich, as to be noticed with surprise by the most 

 incurious observers.^ Neither Mr. White nor Mr. Kirby 

 informs us what particular species formed these immense 

 flights, but it is most probable they belonged to the Hop-fly, 

 Aphis humuli. 



Reaumur tells us that in the Levant, Persia, and China, 

 they use the galls of a particular species of Aphis for dyeing 

 silk crimson.* 



In England, the mischief caused by the Hop-fly, Aphis 

 humuli, in some seasons, as in 1802, has brought the duty 

 of hops down from £100,000 to £14,000. 



A quite common, though erroueous, belief in England is, 

 that Aphides are produced, or brought by, a northern or east- 

 ern wind. Thomson has fallen into the error ; he has also 

 confounded the mischief of caterpillars with that of the Aphis : 



1 B. 3, c. xvi. p. 278. Printed 1613. 



2 Nat. Hist, of Selborne, p. 866. 



3 K. and S. Introd., ii. 9. 



* Reaumur, iii. xxsi. Pref. 



