HEMIPTERA. 191 



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 antenna?, and the legs, are tawny yellow. This 

 species cannot be identical with the willow-louse, Aphis Salicis of 

 Linnaeus, which has a spotted body ; and therefore I propose to 

 call it Aphis Salicti, the plant-louse of willow groves. When 

 crushed, it communicates a stain of a reddish or deep orange color. 

 Some plant-lice live in the ground and derive their nourish- 

 ment from the roots of plants. We annually lose many of 

 our herbaceous plants, if cultivated in a light soil, from the ex- 

 hausting attacks of these subterranean lice. Upon pulling up 

 China Asters, which seemed 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 circum- 

 stance as well as from their peculiar situation, that they never ac- 

 quire wings. Whether these are of the same species as the 

 Aphis radicum of Europe, I cannot ascertain, as no sufficient de- 

 scription of the latter has ever come to my notice. These little 

 lice are attended by ants, which generally make their nests near 

 the roots of the plants, so as to have their milch kine, as the 

 plant-lice have been called, within their own habitations ; and, in 

 consequence of the combined operations of the lice and the ants, 

 the plants wither and prematurely perish. When these subter- 

 ranean lice are disturbed, the attendant ants are thrown into the 

 greatest confusion, and alarm ; they carefully take up the lice 

 which have fallen from the roots, and convey them in their jaws 

 into the deep recesses of their nests ; and here the lice still con- 

 trive to live upon the fragments of the roots left in the soil. It is 

 stated * that the ants bestow the same care and attention upon the 

 root-lice as upon their own offspring, that they defend them from 



* See Kirby and Spence's Introduction to Entomology, Vol. II. p. 9], 92. 



