REMEDIES. 
245 
There are several other species- of Eriosoma or downy lice 
in this State, inhabiting various forest and ornamental trees, 
some of which may also have been introduced from abroad. 
The descriptions of foreign plant-lice are mostly so brief and 
imperfect, that it is impossible to ascertain from them which 
of our species are identical with those of Europe ; I shall 
therefore omit any further account of these insects, and close 
this part of the subject with a few remarks on the remedies 
to be employed for their destruction generally, and some 
notice of the natural enemies of plant-lice. 
Solutions of soap, or a mixture of soapsuds and tobacco- 
water, used warm and applied with a watering-pot or with a 
garden engine, may be employed for the destruction of these 
insects. It is said that hot water may also be employed 
for the same purpose with safety and success. The water, 
tobacco-tea, or suds should be thrown upon the plants with 
considerable force, and if they are of the cabbage or lettuce 
kind, qr other plants whose leaves are to be used as food, 
they should subsequently be drenched thoroughly with pure 
water. Professor Lindley recommends syringing plants, as 
often as necessary to remove the lice, with a solution of half 
an oimce of strong carbonate of ammonia in one quart of 
water, which has the merit of being clean as well as effectual. 
Lice on the extremities of branches may be killed by bend- 
ing over the branches and holding them for several minutes 
in warm and strong soapsuds, or in a solution of whale-oil 
soap. 
Against the depredations of the plant-lice that sometimes 
infest potato-fields, dusting the plants with lime has been 
found a good remedy. Lice multiply much faster, and are 
more injurious to plants, in a dry than in a wet atmosphere ; 
hence in green-houses, attention should be paid to keep the 
air sufficiently moist; and the lice are readily killed by fumi- 
gations with tobacco or with sulphur. To destroy subterra- 
nean lice on the roots of plants, I have found that watering 
with salt water was useful, if the plants were hardy ; but 
