232 
NATURAL HISTORY OF SELBORNE. 
strange and unusual insect, I shall here transcribe a passage 
from a natural history of Gibraltar, written by the Reverend 
John White, late vicar of Blackburn in Lancashire, but not yet 
published : — 
" In the year 1770 a vine which grew on the east side of my 
house, and which had produced the finest crops of grapes for 
years past, was suddenly overspread on all the woody branches 
with large lumps of a white fibrous substance resembling spiders 
webs, or rather raw cotton. It was of a very clammy quality, 
sticking fast to every thing that touched it, and capable of being 
^pun into long threads. At first I suspected it to be the product 
of spiders, but could find none. Nothing was to be seen con- 
nected with it but many brown oval husky shells, which by no 
means looked like insects, but rather resembled bits of the dry 
bark of the vine. The tree had a plentiful crop of grapes set, 
when this pest appeared upon it ; but the fruit was manifestly 
injured by this foul incumbrance. It remained all the summer, 
still increasing, and loaded the woody and bearing branches to a 
vast degree. I often pulled off great quantities by handfuls ; but 
it was so slimy and tenacious that it could by no means be cleared. 
The grapes never 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 ac- 
counted for. Those husky shells, which I had observed, were 
no other than the female coccus, from 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 
* What is here termed coccus vitis vini/erce is now better known as the cocms vini. The male, 
which is less than the female, has two erect wings. The white fibrous substance (mentioned in 
the text) does not exude from the sides of the insect, as above stated, but is excluded together 
with the eggs, and from the same passage. The female dies almost immediately after depositing 
her ova, as is the case with all true insects ; but it is remarkable that she always expires upon 
her eggs, to which her lifeless body adheres, and serves as a covering. This genus comprises 
about thirty known species, all of which are stated to suck the juices of the plants they respec- 
tively infest; one of them, the C cacti, is the valuable cochineal of commerce. Various methods 
have been pjiblished for destroying them; but the most practised, and apparently the most ef- 
fectual, is to crush them, wherever they are seen, with a smooth blunt instrument, and after- 
wards to wash the plant thoroughly with soap and water. — Ei>. 
