THE SUBTERRANEAN PLANT-LICE. 
239 
substance like the bloom of a plum, with four rows of little 
transverse black spots on the back; the top of the thorax 
and the veins of the wings are black, as are also the shanks, 
the feet, and the antennae, Avhich are clothed with black 
hairs; the thighs are reddish brown. This species sucks 
the sap from the limbs, and not from the leaves, of the 
hickory. 
There is another large species, living in the same way on 
the under side of the branches of various kinds of willows, 
and clustered together in great numbers. About the first 
of October they are found in the winged state. The body 
measures one tenth of an inch in length, and the wingS 
expand about four tenths. The stylet is wanting; the body 
is black and without spots ; the wrings are transparent, but 
their veins, the short honey-tubercles, the third joint of the 
antennje, and the legs, are tawny yellow. This species 
cannot be identical with the willow-louse. Aphis Solids of 
Linnaeus, which has a spotted body; and therefore I pro¬ 
pose to call it Aphis Salicti^^^ the plant-louse of willow 
gi'oves. When crushed, it communicates a stain of a red¬ 
dish or deep orange color. 
Some plant-lice live in the ground, and derive their nour¬ 
ishment from the roots of plants. We annually lose many 
of our herbaceous plants, if cultivated in a light soil, from 
the exhausting attacks of these subterranean lice. Upon 
pulling up China asters, which seem to be perishing from 
no visible cause, I have found hundreds of httle lice, of a 
white color, closely clustered together on the roots. I could 
never discover any of them that were winged, and therefore 
conclude from this circumstance, as well as from their pecu¬ 
liar situation, that they never acquire wings. Whether these 
are of the same species as the Aphis radicum of Europe, 
I cannot ascertain, as no sufficient description of the latter 
[ 10 The name Salkti was long ago appropriated by Schrank to a very different 
species of Aphis, inhabiting Europe. This name must therefore fall as a synonyme 
to some other which may be applied to it. It might be called Aphis Salicicola. — 
Uhler.] 
