:
in summer 60 degs., rising to 75 degs. with sun heat, night 60 degs. to
65 degs., in winter 50 degs. to 55 degs. The hardy species will, of course,
bear the ordinary temperatures of this country; but, to enable them to
withstand a very cold winter, they must be kept as dry as possible. In
the colder parts of England it is not advisable to leave any of these
plants outside during winter.

Insect Pests.--Notwithstanding the thickness of skin characteristic of
almost every one of the Cactuses, they are frequently attacked by
various kinds of garden pests when under cultivation, and more
especially by mealy bug. There is, of course, no difficulty in removing
such insects from the species with few or no spines upon their stems;
but when the plants are thickly covered with clusters of spines and
hairs, the insects are not easily got rid of. For Cactuses, as well as
for other plants subject to this most troublesome insect, various kinds
of insecticide have been recommended; but the best, cheapest, and most
effectual with which we are acquainted is paraffin, its only drawback
being the injury it does to the plants when applied carelessly, or when
not sufficiently diluted. A wineglassful of the oil, added to a gallon
of soft water, and about 2oz. of soft soap, the whole to be kept
thoroughly mixed by frequently stirring it, forms a solution strong
enough to destroy mealy bug. In applying this mixture, a syringe should
be used, or, if the plants are to be dipped overhead, care must be taken
to have the oil thoroughly diffused through the water, or the plant,
when lifted out, will be covered with pure paraffin, which does not mix
properly with water, but swims upon the surface if allowed to stand for
a few moments. The plants should be laid on their sides to be syringed
with the mixture, and after they have been thoroughly wetted, they may
be allowed to stand for a few minutes before being syringed with pure
water. Plants that are badly infested with mealy bug should be syringed
with the paraffin mixture once a day, for about a week. It is easy to do
serious harm to these plants by using a stronger solution than is here
recommended, and also by not properly mixing the oil with the soap and
water; and the amateur cannot, therefore, be too careful in his use of
this excellent insecticide. It would be easy to recommend other
insecticides, so called, for Cactuses; but whilst they are less
dangerous to the plants, they are often as h