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 emigration, 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.[895] A similar emigration of these insects Mr. Kirby once witnessed, 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 autumn, 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.[896] 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.[897] 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 erroneous, belief in England is, that Aphides are produced, or brought by, a northern or eastern wind. Thomson has fallen into the error; he has also confounded the mischief of caterpillars with that of the Aphis: For oft, engendered by the hazy north, Myriads on myriads insect armies warp, Keen in the poison’d breeze, and wasteful eat Through buds and bark into the blackened core Their eager way. A feeble race! Yet oft The sacred sons of vengeance, on whose course Corrosive famine waits, and kills the year. Coccidæ--Shield-lice. The Kermes-dye, or scarlet, made from the _Coccus ilicis_ of Linnæus, an insect found chiefly on a species of oak, the _Quercus ilex_, in the Levant, France, Spain, and other parts of the world, was known in the East in the earliest ages, even before the time of Moses, and was a discovery of the Phœnicians in Palestine, who also first employed the murex and buccinum for the purpose of dyeing.