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cyanic acid gas. However, owing to the dangerous nature of the 
last named remedy, it was thought inadvisable to make use of 
this method of extermination. Owing to the active movements of 
this pest when in the adult stage, it is rather difficult to exterminate 
it by means of spraying, since it is necessary for the spray actually 
to hit the insect; but by spraying two or three times at intervals 
of a day or two, the pest may, for the most part, be overcome. 
Other sucking insects that are almost invariably present in plant 
houses (and the conservatories of the Brooklyn Botanic Garden 
are not exceptional in this respect) are the mealy bug (Dactylopius 
destructor), several species of scale insects belonging to the 
Coccidae, and the red spider (Tetranychus telarius). Mealy bug 
and scale insects can be destroyed by constant spraying with a 
contact spray of some kind, the most effective preparation being 
kerosene emulsion. The spraying, however, has to be repeated 
often, and the more efficacious method is, where the nature of the 
plants permit, to wash off the insects with a sponge and soapy 

-water. Red spider flourishes in a dry atmosphere, and the best 
methods of control are the maintenance of humidity and spray- 
ing with clear water, which must be applied to the underside of 
the leaves, where the red spider has his habitation, with a suff- 
cient force to break the webs. Potassitm sulphide, at the rate 
of one or two ounces to three gallons of water, applied in the 
same way, is also helpful, but has the disadvantage of discoloring 
any paint with which it comes in contact. 
A sucking insect, which amongst horticulturists goes by the 
name of the white tailed mealy bug, lantane bug, and white fly, 
has been observed on: plants of Coleus. Te ee (Orthezia 
insignis) belongs to the Coccidae and is extremely difficult to 
control. The most effective preparation to use against these in- 
sects is kerosene emulsion. 
Plants out of doors have been attacked by other sucking insects, 
in addition to aphids; namely, the leaf hopper, and one of the 
lace bugs (rhododendron fly) which have attacked the rhodo- 
dendrons. 
Of biting insects, those which have caused the most trouble 
are the larvae (caterpillars) of various kinds of moths and butter- 
flies. The principal objects of attack have been the willows, which 

