850 
ANNUAL REPORT OF NEW YORK 
POPLAR. LEAVES. 
In connection with the Poplar-stem gall-louse I introduce this species, 
it is so very similar, although I know nothing of its habits, beyond the 
fact that it was noticed in great numbers upon a Balsam poplar, P. balsami- 
fera, Linn., upon a warm sunny day in the middle of October, wandering 
up and down the trunk of the tree, in company with a species of Aphis. 
These were winged females, one of which was observed to extrude a small 
larva 0.02 in length, of a pale yellow color with watery white head and 
legs. 
As noticed at that timo, these flics were black, slightly dusted over with a glaucous gray 
powder; the abdomen dull green with a small coating of white flocculcnt wool, its oppo¬ 
site sides parallel and its tip abruptly rounded; the antennas short, thick and thread¬ 
like; the wings dull hyaline, their rib-vein black and the oblique veins slender and blackish 
with the basal third of the third vein abortive and the fourth vein perceptibly thicker 
towards its base; and the small branch of tho rib-vein bounding the anterior end of the 
stigma having nearly the same thickness with the rib-vein. 
355, Poplar-bullet gai.l-louse, Pemphigus Populi-globuli , new species. 
Iu July, on the leaves of the Balsam poplar slightly above their base, 
an irregular globular apple green gall the size of a bullet, projecting from 
the upper surface of the leaf, with a curved mouth-like orifice on the under 
side, the cavity within containing numerous small pale green and smaller 
dusky lice with the end of their bodies covered with short white cotton¬ 
like threads, and larger winged ones which are of a black color, with the 
abdomen dusted over with white meal and with thin white woolly fibres on 
the back, and their antennm reaching the base of the wings, which are 
clear hyaline, their veins slender and white or colorless, except the outer 
marginal vein which is black to the end of the stigma, and also tho rib- 
vein, which is much thicker at its apex; their length 0.07 and to the tip of 
the wings 0.11. 
I find several galls of this kind on a Balsam poplar in my yard, at the 
moment of sending these pages to the press. That I might render the 
history of the preceding species more complete, I wanted to think I here 
had the same insect at its summer employment which I had previously met 
with in autumn after its work for the season was closed. But on placing 
the two side by side I see some diflercnces between them, so slight that it 
may not be in our power to distingish them with any degree of confidence 
iu preserved specimens iu the*cabinet, yet so palpable that I am compelled 
to regard them as distinct species. And as in the gall-flies on oaks so also 
in the gall-lice on poplars it would seem that Nature designed to show how 
closely alike she could make several of these minute insects, and then 
placed them in dissimilar galls that the observer of her works might be 
assured they were really different the one from the other. 
These flies differ from those of P. Popularia in being uniformly a sizo smaller, with 
wings more clear and glassy, their veins more slender and quite colorless, the stigma less 
opake than in that and other species of these insects, and the rib-vein more thick where it 
bounds the inner margin of the stigma and especially at its apex. Tho oblique branch of the 
rib-vein bounding the anterior end of tho stigma is more slender than the marginal vein. 
