STATE AGRICULTURAL SOCIETY. 
851 
POPLAR. LEAVES. 
The fourth oblique vein is slightly thicker at its base, where it is also a little dusky. The 
abortive basal third of the third vein is traced by a very slender line, which here appears to 
be more distinct than in any of the kindred spocies. The inner margin shows the same duski¬ 
ness for a short distance at and forward from the tip of the first vein that is common to the 
insects of this family. The abdomen is dusted over with a white mealy powder, with a black 
band on the hind part of each segment from the absence of this powder. 
The gall grows from the midvein of the leaf slightly above the point 
where it passes into the stem, instead of at or slightly below this point 
where the Poplar-stem gall first described is situated. And hereby 
this gall has a narrow portion of the base of the leaf below it. It 
grows either wholly upon the upper side of the leaf, or with a small portion 
protruding outwards from the under side. It is of a spherical form, but 
more or less irregular and with the surface uneven. It varies from a little 
over a quarter to a half inch in diameter, and is of a pale apple green 
color, sometimes with a deep carmine red cloud on the side most exposed to 
the light. Its walls arc nearly a tenth of an inch thick and very juicy 
and brittle, but become, as in other galls, more dry, wilted, and leath. r- 
like when old. The midvein where the gall is situated becomes thickened 
and curved or otherwise distorted, and the orifice of the gall opening along 
its side partakes of this curve. 
The winged flies are females, producing eggs of a dull wax color, the 
eyes of the inclosed larva appearing like two black dots near one end, as 
in other instances in this genus. These eggs hatch within a few moments 
after they are extruded. Before they leave the interior of the gall these 
flies are mostly of a pale lurid green color with the knees and feet dusky, 
and only the antennae and the'thickened tip of the rib-veins are then of the 
black hue which the body acquires after its exposure to the light. And 
after they have come abroad the under side of the abdomen often retains 
this same lurid green color. 
305. Poplar-vein gall-lodse. Pemphigus Populi-vcnw, new species. 
In July an oblong compressed excrescence like a cock’s comb, of a light 
red color varied with pale yellow, growing from the midvein of Balsam 
poplar leaves on their upper side with an orifice on the opposite under 
side ; a cavity within containing a multitude of lice and their white cast 
skins, interspersed with a whitish meal-like powder; those with wings being 
black, with coarse thread-like antennae reaching to the base of the wings, 
which, with their oblique veins, arc pellucid and colorless, the coarse rib- 
vein being blackish and more thick at its tip along the inner margin of 
the stigma, and the vein of the outer margin being blackish and somewhat 
coarse from its base to the stigma ; its length 0.05 and to the tip of the 
wings 0.08. 
A number of these galls may sometimes be observed upon the leaves of 
particular trees. They are nearly semicircular and half as high as long, 
being usually over a half inch in length, with an uneven surface, their 
walls thick, brittle and suoculeut. They arc commonly placed near the 
