49 
ce upon roots not attended by ants, or to find ants frequenting a 
ill of corn which is not infested by root-lice. There can be no 
jubt that the latter are carried from place to place by the ants; and 
ley are probably scattered by them through the corn fields in 
)ring, especially in cases where the ground has not been previously 
ifested by this Aphis.* 
INJURIES TO BROOM-CORN AND SORGHUM. 
My observations on this species in fields of sorghum and broom- 
irn began at too late a date to give me any direct information as 
> the work of this louse upon the roots in spring; but we have 
luch reason to believe, both from analogy and from the condition 
f the sorghum at this time, that root-lice had infested this plant in 
manner similar to that in which they make their first attack upon 
orn. 
Their effect upon the foliage is to redden and curl the growing 
aves, injuring the plant much more seriously than the Chaitophorus 
[ready discussed, not only depriving it of the healthy activity of 
s leaves, but likewise arresting the development of those on which 
le further growth of the plant especially depends. When great 
umbers of these plant-lice are collected upon the leaves at the tip 
f the stalk, the latter will turn yellow or red. 
Whether or not they have any injurious effect upon the tops of 
le sorghum upon which they cluster later in the season, I am 
nable to say; but they are said to injure the quality of the “brush’' 
E broom-corn by staining it red, doubtless through the action of a 
ingus which almost always follows the plant-louse injury upon 
3 th 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, 
ad well known as a universal check upon the multiplication of 
iant-lice in general. The most effective seems to be a parasitic 
phidius which I have seen totally exterminate entire colonies, so 
fat among hundreds of swollen bodies of plant-lice upon the leaves 
f a hill of corn, not a single living individual was to be found. 
* I have this season demonstrated that the corn root-louse may live, at least at times, 
mnoneof the grass-like weeds most abundant in corn fields, Panicum glabrum. We 
ansferred, in July, to the Laboratory, some specimens of Schizoneura panicola infesting 
e roots of grass, placing in the box of earth with them some Panicum glabrum . upon 
hichitwas hoped that the Schizoneura would fix itself and continue its development. 
| hesc specimens, however, apparently died, as neither they nor any plant-lice which 
; )uld have descended from them were seen again; but upon the blades and heads of Pani- 
im a hundred or more individuals of the eorn plant-louse afterwards appeared. The 
’ass bad been carefully searched for plant-lice when placed in the breeding cage, but 
lubtless a few individuals were overlooked, either in the earth or beneath the sheaths of 
ie leaves. In the absence of other food, they bred and multiplied freely upon the grass, 
id in August were represented by all the aerial forms of pupa, apterous, and alate 
j males. There were no lice of any kind upon the roots. 
L 
