PLANT LICE. 177 
from the lice is much less apt to occur, and the principal danger 
period, namely, the first two or three years after planting in the 
orchard, will pass in safety. The value, as a means of protec- 
tion, of thorough cultivation and good care of young orchards 
can not be too strongly insisted upon. Vigorous growing trees 
have a decided power of resistance or are able to sustain with 
comparatively little damage the presence of the root-lice, while 
ill-cultivated and neglected orchards are especially liable to in- 
jury.” 
The Woolly-louse of the Apple has, like most other plant- 
lice, a large number of enemies; these will be described later. 
SUB-FAMILY APHIDINA. 
(Typical Plant-lice). 
This is a very large sub-family, frequently divided into a 
number of sub-families, but for purposes of this report it is 
not necessary to do so. Most of the species live above ground, 
on the surface of leaves or twigs of all kinds, and none produce 
true galls. They include such genera in which the third dis- 
coidal vein of the front wings is twice forked; the hind wings 
have two discoidal veins; the honey-tubes are usually well de- 
veloped, and are sometimes tuberculiform or are obsolete. 
The genus Lachnus, to which the largest of our species of 
Aphidide belong, have the six-jointed feelers about half as long 
as the body; the very long beak reaches to or beyond the third 
pair of cox, and is sometimes even much longer. The honey- 
tubes are short, not longer than broad, often tuberculiform, or 
are even wanting. 
Lachnus dentatus Le Baron. (The Toothed Willow Plant-louse). 
“This species is found in October and November in colonies 
on the under side of the branches of the gray willow; and occa- 
sionally, but apparently accidentally, on trunks of small nursery 
apple trees. The winged individuals measure about one-sixth 
of an inch to the tip of the abdomen, the wings expand about 
half an inch. Black, abdomen dark, and ash color, with six 
transverse rows of black dots. Antennz as long as the head and 
thorax. Front wings with a very long stigma, the third vein 
with two forks, as usual in this genus. Honey-tubes reduced to 
