Feb.] the HOT-HOUSE. X59 
to touch each other. And as they pierce that part of the leaf imme- 
diately under the scale with their proboscis, they thereby not only 
draw out the nutricious juices themselves, but also destroy the tubes 
through which they flow. The upper parts of the leaves being thus 
deprived of their nourishment, consequently die. But these insects 
do not attack the roots, as has been frequently asserted. 
3. The white mealy crimson-tinged insect. This insect, as 
well as the former, I have not found to be noticed by naturalists. 
This species also has all the characters of a coccus, but in all 
probability belongs to another genus. For whereas the two former 
species are undoubtedly oviparous, this seems to be viviparous. 
It is most probable that the young ones remain some time in the 
mealy down of the mother till they have acquired strength, and 
are arrived at such a degree of perfection, as to enable them to 
support themselves v/hen they forsake the parent insect and dis- 
perse to different parts of the plant. 
When this species is first perceived on the leaves of the pine, it 
appears to be nothing more than small particles of meal or powder 
collected together; but in a few days it assumes the form of a louse 
or bug, thickly covered with a fine meal or down of an oval form 
on its upper, and very flat on its under side, from whence proceed 
its legs, which are six in number. These, as well as many other 
particulars in the above, and preceding descriptions, are not to be 
distinguished without the help of glasses. 
The last described species is of a more pernicious nature than 
the former; it attacks every part of the plant, from the top of its 
fruit even to the most extreme parts of its roots. These animals 
wedge themselves in between the protuberances of the fruit in a 
most surprising manner, so as not to be got out without difficulty, 
which not only makes the fruit appear very unsightly when it be- 
comes ripe, but by robbing it of its nutricious juices is the cause 
also of its wanting flavour and being ill tasted. 
But the bad effects of this species on the roots of the plants are 
yet of a far worse consequence; for there, even at the bottom of the 
pots, they increase with an uncommon degree of rapidity, so as 
to become very numerous, and in the end to destroy the principal 
roots of the plants. 
There have been various methods used for the extirpation of 
these insects, such as shifting the plants and washing their roots; 
decoctions from tobacco, wormwood, walnut leaves, henbane, and 
other herbs of a bitter or poisonous quality. Some have added to 
the above snuff', sulphur and pepper. These and many other reme- 
dies have been tried to very little purpose; at length, Mr. William 
Speechly, then gardener to the Duke of Portland, England, dis- 
covered and recommended in his excellent Treatise on the Culture 
of the Pine-apple, the following receipt, which he asserts "for the 
destruction of these insects, bad never failed him; its efficacy 
being confirmed by nine years' experience." 
THE receipt. 
Take one pound of quicksilver^ put it into a glazed vessel, and 
X 
