49 
lice upon roots not attended by ants, or to find ants frequenting a 
hill of corn which is not infested by root-lice. There can be no 
doubt that the latter are carried from place to place by the ants; and 
they are probably scattered by them through the corn fields in 
spring, especially in cases where the ground has not been previously 
infested by this Aphis.* 
INJURIES 'TO BROOM-CORN AND SORGHUM. 
My observations on this species in fields of sorghum and broom- 
corn began at too late a date to give me any direct information as 
to the work of this louse upon the roots in spring; but we have 
much reason to believe, both from analogy and from the condition 
of the sorghum at this time, that root-lice had infested this plant in 
a manner similar to that in which they make their first attack upon 
corn. 
Their effect upon the foliage is to redden and curl the growing 
leaves, injuring the plant much more seriously than the Chaitophorus 
already discussed, not only depriving it of the heaithy activity of 
its leaves, but likewise arresting the development of those on which 
the further growth of the plant especially depends. When great 
numbers of these plant-lice are collected upon the leaves at the tip 
of the stalk, the latter will turn yellow or red. 
Whether or not they have any injurious effect upon the tops of 
the sorghum upon which they cluster later in the season, I am 
unable to say; but they are said to injure the quality of the “brush” 
of broom-corn by staining it red, doubtless through the action of a 
fungus which almost always follows the plant-louse injury upon 
both the leaves and the tops of all the plants attacked by it. 
NATURAL ENEMIES. 
The natural enemies of this species are those already referred to, 
and well known as a universal check upon the multiplication of 
plani-lice in general. The most effective seems to be a parasitic 
Aphidius which I have seen totally exterminate entire colonies, so 
that among hundreds of swollen bodies of plant-lice upon the leaves 
of a hill of corn, not a single living individual was to be found. 
*T have this season demonstrated that the corn root-louse may live, at least at times, 
upon one of the grass-like weeds most abundantin corn fields, Panicwm glabrum. We 
transferred, in July, to the Laboratory, some specimens of Schizoneura panicola infesting 
the roots of grass, placing in the box of earth with them some Panicum glabruwm, upon 
which it was hoped that the Schizonewra would fix itself and continue its development. 
These specimens, however, apparently died, as neither they nor any plant-lice which 
could have descended from them were seen again; but upon the blades and heads of Pani- 
eum a hundred or more individuals of the eorn plant-louse afterwards appeared. The 
grass had been carefully searched for plant-lice when placed in the breeding cage, but 
doubtless a few individuals were overlooked, either in the earth or beneath the sheaths of 
the leaves. In the absence of other food, they bred and multiplied freely upon the grass, 
and in August were represented by all the aerial forms of pupa, apterous, and alate 
females. There were no lice of any kind upon the roots. 
