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with a curved orifice or mouth on the under side; within these reside 
the lice, some of which are pale green, others ' very small and dusky, 
the larger winged ones of a black color. These are found in this con¬ 
dition in July. The winged individuals differ from P. popularia as 
follows: They are uniformly smaller, wings clearer and veins more 
slender and colorless, except the marginal vein, which is black to the 
stigma; the abortive basal third of the third vein is traced by a very 
slender line, which appears to be more distinct than in any of the 
allied species; the abdomen is dusted over with a white powder, with 
a black band on the hind part of each segment. Length to the tip 
of the abdomen 0.07 of an inch; to the tip of the wings u.ll of an 
inch. 
The gall which this species produces grows from the mid-rib of the 
leaf slightly above the junction of the blade with the petiole. It 
grows either wholly on the upper side of the leaf, or with but a small 
portion protruding from the under side. The winged individuals ac¬ 
cording to Dr. Fitch are females, which produce eggs of a dull wax 
color, the eyes of the enclosed larva appearing like two black dots 
near one end. These eggs hatch in a few moments after they are 
deposited. The so called eggs of Dr. Fitch, are doubtless the thin 
egg-like sacks which we have heretofore mentioned, in which the larvse 
are enclosed; hence, this method of reproduction must properly be 
classed as viviparous, or, perhaps more correctly ovo-viviparous. 
Pemphigus populi-vesle. Fitch. The Poplar-vein Gall louse. 
This species forms an oblong, compressed, cockscomb shaped gall, 
on the mid-veins of the leaves of the balsam poplar. These are situ¬ 
ated on the upper side of the leaf, with an orifice which opens on 
the under side; they are of a light red color, varied with yellow. 
The cavity within as in the others, contains a number of lice. These 
galls are nearly semi circular, and half as high as they are long, being 
usually over half an inch in length, with an uneven surface; their walls 
thick 'and britle. They are generally placed near the base of the leaf, 
though sometimes in its middle. 
The following is a description of the species as given by Dr. Fitch: 
The female larvae are dusky on the body and legs; and are quite 
small, measuring about 0.25 of an inch in length; straight along each 
side and slightly narrowing from behind forward. The male larvae 
are much less numerous, and double their size; are pale dull green 
with whitish antennae and feet. 
The adult wingless female is as broad as long, measuring from 0.04 
to 0.05 of an inch in length, the hind end usually being concave or 
notched, and the abdomen elevated or humped in the middle; pale 
dusky with two rows of snow white dots, formed of white powdery 
matter, along each side of the back, the dots of the inner row being 
more numerous than those of the outer row; head dark, legs dull yel¬ 
low and feet dusky. 
The winged individuals black, with coarse thread-like antennas, 
reaching to the base of the wings. The wings are pellucid and color- 
