INSECTS INJURIOUS TO CORN. 135 



by two small openings surrounded by narrow brownish 

 rings. The latter species is common upon the roots of 

 grasses, among which may be mentioned bhie grass, 

 timothy, and Paniciim glahruw, and though it rarely 

 becomes of any great economic importance, it is well to be 

 able to distinguish it from the more injurious Corn Eoot- 

 louse. 



Distrihution and Food. — The Corn Root-louse has been 

 reported from Illinois, where it occurs in all parts of the 

 State, Maryland, Xew Jersey, Delaware, Indiana, Ohio, 

 Kentucky, Minnesota, and Nebraska, so that it doubtless 

 occurs to some extent through the whole Corn Belt. 

 Besides broom-corn and sorghum no other cultivated crop 

 has been known to have been injured l)y this pest, though 

 it feeds in early spring and even as late as June upon 

 the roots of smaitweed, purslane, Fortiilaca solcracco, 

 ragweed, foxtail, and crab-grasses. The economic bearing 

 of its feeding upon these weeds will be seen in discussing 

 the life-history. 



Care of the Ants. — If you will break open the nests of 

 the small brown ants {Lasius niger and var. alienvs), 

 which are common in corn-fields which have been infested 

 w^ith the root-louse, during the winter, you will doubtless 

 find many of the little black aphis-eggs, which have been 

 carefully stored by the ants and which will be well cared 

 for by them during the winter. They are of a glossy 

 black color and an oval shape, and will sometimes be found 

 in small piles in the chambers of the ants^ nests. On 

 warm days the ants bring them up to the warmer surface- 

 soil, and in cold weather carry them far down into the 

 unfrozen earth. With the appearance of the young smart- 

 weed plants [Polygo7ium pcrsicaria) in early spring, the 



