=> 
[9 ys) 
Many facts which have come under my observation go to show 
that a similar service is rendered to the lice of our corn and sor- 
ghum fields by this same everywhere abundant ant. 
Summary. 
By way of recapitulation of the facts relating to the plant-lice 
infesting sorghum and broom-corn, we may say briefly that four of 
these species are now known to injure these crops, three of them 
affecting the foliage and tops, and the fourth confining its injuries 
to the roots. It is also probable that at least one of those hitherto 
found only upon the leaves, likewise seriously injures the plant by 
draining the sap from the roots early in the season. All four of 
these species continue their depredations until October, retarding the 
growth of the plant by appropriating the sap and deadening the leaves, 
and in broom-corn further injuring the crop by staining the brush. 
The first of these species, which may be called the yellow sorghum 
plant-louse, described here under the name of Chaitophorus flavus, may 
be distinguished from the others by its nearly uniform lemon color in 
all stages, and by the fact that it attacks only the lower leaves of 
the plant, upon the inferior surface of which it clusters, usually 
nearest the midrib, having the effect, when numerous, to deaden 
the leaves entirely for a variable distance above the ground. On a 
more minute examination, it may be recognized by the fact that the 
antenne are but _five- jointed, while in the other aécrial species they 
are six-jointed, that the honey-tubes are low, conical tubercles, and 
that the back of all the forms is ornamented with several longitudinal 
rows of small tubercles, bearing stiff bristles. 
The second species is the well known plant-louse of Indian corn, 
Aphis maidis, and occurs chiefly upon the upper leaves of the plant 
until the head appears, when it attacks this also. The color of 
this species is dark green in all except the winged forms, and in 
these the head and thorax are black. The antenne are short, not 
more than two-thirds the length of the body; the honey-tubes are 
prominent, cylindrical, shghtly enlarged in the middle and expanded 
at the tip. ‘The slender terminal portion of the antenne, called in 
this paper the filament, is only about equal in length to the third 
joint of the same. 
The third aérial species is similar in general appearance and in 
situation to the corn Aphis just described, but may be distinguished, 
upon careful examination, by the fact that the filament of the 
antenne is one-third its whole length, being nearly twice as long 
as the third joint, while the cornicles are cylindrical and taper 
regularly from the base to the tip. The root-louse is white or 
yellowish-white, and easily recognized by the fact that it is entirely 
destitute of honey-tubes, these being replaced by circular pores 
which open upon the surface. The antenne will likewise serve for 
its recognition, as they are without the slender, filament-like termi- 
nal portion with which all the other species are furnished. From 
the root form of the corn plant-louse, which sometimes occurs in 
connection with it, this species may be distinguished by the two 
characters last mentioned—the absence of the honey-tubes and of 
the antennal filament. 
