757 
No. 145.] 
from rains and the night dews. The leaf-stalks also become bent, 
so that all the leaves growing upon a twig are, in badly-infested 
trees, turned backwards, pressing against the twig, and thus 
shielding that part of the colony which is located thereon. An 
infested tree may be distinguished at a distance of several rods 
by the leaves on the ends of its twigs being thus turned back¬ 
wards, instead of standing freely out in their natural position. 
The bark of the limbs, and the surface of the leaves also, becomes 
blackened as if it had been smoked by the flame of a candle or 
other burning substance. This blackness does not rub off upon 
white paper, but Mr. Briggs informs me that washing the bark 
with a solution of sal soda removes it entirely. He had observed 
this black appearance of his trees before he noticed the lice which 
caused it, and seeing a newspaper-recommendation of this wash 
for cleansing trees, he applied it to four of those in his orchard. 
The next day he was astonished at finding myriads of these lice 
crawling down and up the trunks of these four trees, and upon 
the ground they were heaped together in a ring around their 
bases. The alkaline matter in this wash had evidently tinctured 
the sap of the tree, and made it unpalatable to these insects, and 
they endeavored to emigrate to some place free from it, but on 
reaching the ground they knew not where to go, and many, there¬ 
fore, travelled up the trunk again in search of some other avenue 
of escape. 
A strong disagreeable smell is also emitted from trees that are 
badly infested with the apple plant-louse, and when a person has 
been examining infested twigs this smell remains upon his hands. 
The odor is peculiar and very loathsome, and reminds me of the 
smell of stale fish more than anything else with which I am able 
to compare it. 
All the insects of this family secrete copiously a sweetish fluid, 
called honey dew. This is ejected from the two little horns, or necta¬ 
ries, which project one on each side of the hind part of their bodies. 
Often a clear drop of this fluid may be seen at the tip of one or 
both of these horns. This fluid, falling upon the leaves and eva¬ 
porating, gives the leaves, under a colony of these lice, a shining 
