The winged root louse lias been frequently taken on the 
leaves of corn during the month of June—from the 9th to the 
24th precisely—and in the latter instances has been frequently 
found breeding* there to some small extent; but attempts to 
raise these young on corn or broom corn, or to follow them 
in the field to the adult condition, have all thus far failed. On 
the other hand, the first observed appearances of the aerial louse 
(during the latter part of July) come after just about the in¬ 
terval required by the hypothesis of an origin from the winged 
root form. 
The aerial aphis grows much more freely on .sorghum and 
broom corn—especially the former—than on maize itself, but 
no experiments have as yet been made with the transfer of the 
corn-root louse to the leaves of either of these plants. 
In our large cloth-covered breeding cages inclosing corn 
abundantly stocked with root lice and ants, we have occasion¬ 
ally got an appearance and temporary continuance of the root 
form on the stalks or leaves, running up to a week with the 
usual production of young, and in two instances, out of about 
thirty experiments tried, aerial lice appeared later on the corn 
plants thus inclosed. A possible source of error appeared, 
however, in the fact that where the leaves of the growing corn 
pressed against the cheese-cloth covering, winged viviparous 
aerial lice were seen crawling about outside, where their young 
might easily have passed through the meshes of the cloth and 
reached the plant within. This year, with a very large cage 
covering four planted hills throughly stocked with root lice 
there has not been a trace of the aerial louse; and all attempts 
to evolve it by directly transferring the root louse to the 
leaves have failed. 
Passing now to the other end of the season we find that the 
aerial lice continue to breed generation after generation of both 
winged and wingless viviparous females until the autumnal cold 
and the perishing of their food plants destroy them en masse, 
leaving behind no trace or remnant of a hibernating brood, nor 
evolving, so far as we have been able to discover, any oviparous 
generation. These aerial lice pass rapidly and freely from 
plant to plant in the fall, concentrating thus on the latest 
remnants of green vegetation about the corn, and spreading 
likewise to the perennial grasses around the borders of the 
field. We have dissected them by the hundred at this season, 
finding only females, and these all viviparous, and have bred 
them in warm breeding rooms throughout the winter, no less 
than nine generations in succession occurring between October 
7 and the 8th of March. In all these winter generations no 
trace of oviparous females occurred, and no variation of tem¬ 
perature or exposure made any appreciable change in the form 
or habit of the louse. 
The aerial louse is extremely like the apple louse {Aphis mall). 
and its general disappearance in autumn from the corn at a 
time when this last species is laying its eggs freely on the apple 
