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 antenna?, which 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 wings are transparent, but 

 their veins, the short honey-tubercles, the third joint of the 

 antennaa, -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 

 groves. 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 little 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 S/tlicti was long ago appropriated by Schrank to a very different 

 species of Aptrig. Inhabiting Europe. This name must therefore fall as a synonyme 

 to some other which may be applied to it. It might be called Aphis Sahcicola. 

 UHLKR.] 



