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 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 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.*