99 
salt in one gallon of water, and to brush the trees 
all over with it. 
Mr. Harrison’s receipt for the destruction of 
their eggs will avail nothing ; for, providing there 
was eggs produced by this species, (a thing I 
very much doubt, as adverted to a few pages pre- 
ceding this) the ingredients he has laid down 
are not likely to destroy them, as we find they will 
not destroy those eggs which are produced by those 
species of the Aphides which produce eggs, and it 
will be a great chance if they meet with the insects 
themselves, if put on after all the leaves are off the 
tree, as will be seen by referring to the descrip- 
tion of their process, I would just observe that, 
providing there are eggs produced from this 
species of the Aphis, they are not produced by the 
Fly seen in the autumn months, as Mr. Harrison 
supposes, for it is clear the perfect insects estab- 
lish their progeny viviparously, as before related, 
and if eggs are produced it will be from their 
immature progeny. 
The tobacco dust or snuff will destroy the 
insects ■, but the process is tedious, especially upon 
a large scale. 
Smoking, as severally directed by Harri- 
son, Mackenzie, and Carr, will intoxicate 
them, and not prove quite so effectual as done in 
forcing houses, on account of the smoke escaping 
much sooner, so that many will fall to the ground, 
and will again recover. It is therefore neces- 
sary to destroy them while on the ground, as 
