STATE AGRICULTURAL SOCIETY. 
84 1 
POPLAR. LEAVES. 
same bullet-like excrescences were then growing on the poplars everywhere 
in and around the city, and were so numerous on particular trees that 
scarcely a leaf could be found which was destitute of them. The speci¬ 
mens shown me were taken from the River poplar or Cotton tree, (i opu- 
lus Icevigata , Aiton.) 
Three years since, on the twenty-seventh of June, a leaf which had 
fallen from a Lombardy poplar in my yard, was found wilted and some¬ 
what shrivelled, which showed on the middle of its stalk, a bullet-like 
gall, of which, and the insects within it, full memoranda were taken, 
which describe these Albany leaves perfectly ; and when the leaves fell 
from this tree in autumn, a few were found among them, more faded than 
the others and having these same excrescences, but placed at the base of 
the leaf instead of on the middle of its stem, and the galls having now 
become black, dry and hard. 
These excrescences are about a half inch in diameter and somewhat 
more long than thick. They arc of a pale green color, similar to that of 
the stalk on which they grow. At their base they are wrinkled with 
parallel plaits running from the excrescence a short distance downwards 
upon the stem on which they grow, which stem is slightly thickened at this 
point. On their upper side the surface is rough from numerous small 
smooth elevations resembling pimples, some of them round, others oblong, 
which are green at first, but soon become whitish and remain of this color 
after the gall is dead and black. They are of a weak leathery texture, 
having a large cavity inside, the walls being the thickness of thin leather. 
The cavity within is completely filled with a confused mass of little lice, 
sprinkled over and obsured-by a white meal-like powder, and intermingled 
with them are a multitude of white shrivelled cast skins. These lice when 
more particularly examined, are fouud to be of three different kinds, 
namely, larvae, pupae, and perfect or winged flies. In the first gall which 
I inspected more than a hundred and fifty of these insects were counted. 
The Laiivas, or smallest insects in those galls, are about 0.03 long, but variable in size. 
They are of a dull white color with the knees a little dusky and the eyes blackish. They are 
oval, slightly narrower anteriorly, with their sutures well marked by transverse impressed 
lines. 
The Pupa 2 are similar to the larvm in color and form, but of a larger size, and particularly 
distinguished by having little oval scales, which are the wings in their rudimentary state, 
pressed a'gainst each side of the body. Their feet as well as their knees are dusky, of a 
much darker shade in some than in others, and in some individuals the head and thorax have 
a reddish tinge. Their length is about 0.07. These were far the most numerous individuals 
in the gall first examined. 
The Winged flies are of a blue black color throughout, sometimes with the base of the 
abdomen and of the legs dull brownish yellow, and when newly hatched the under side or 
even the whole of the abdomen is dusky lurid greenish. The wings are closed together hori¬ 
zontally upon the back before the fly has left tho gall, but after it has used them, they are 
held together above the baok in a stoop roof. They are whitish hyaline, not clear, being like 
the body so dusted over and dimmed with white moal-liko powder that they appear almost 
opake until this extraneous matter is brushed ofF. The vein forming tho outer margin is 
coarse and blue-black from tho base to tho commencement of tho stigma, and very fine and 
slender beyond that poiut. Tho rib-vcin also has tho samo color and is still more thick and 
