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tlie first; the fourth or stigmal vein is of equal robustness with the 
first and does not taper; in the hind wing the apex of the second 
discoidal is nearly twice as far from the apex of the rib-vein as it is 
from the apex of the first -discoidal. 
Length to tip of wings .09- 12 inch; expanse .20-.25 inch. The 
stigma is three times as long as wide, very acute at the basal end, 
and not materially wider than the costa. Found winged specimens 
, May 25th, in company with many larvae and pupae, and obtained others 
; in the course of June, all in the nest of the same yellow ant be tore 
mentioned. A specimen of the wooly secretion of the larvae which I 
have preserved appears under the lens like cotton wool, but at least 
ten times as fine and snowy white. 
Pemphigus pseudobyrsa. Walsh. 
Syn. Byrsocripta pseudobyrsa. Walsh. 
Pale obscure greenish, pruinose. Antennae sometimes obfuscated, 
always with the 6th joint unguiculate. Thorax blackish pruinose. 
Joints of abdomen with obscure fuscous fasciae. Legs with the tarsi, 
and sometimes the tip of the femora, obfuscated. V ings whitish sub¬ 
opaque, costa and stigma yellowish; veins hyaline except the costais 
which are pile, yellowish-brown, the subcostal generally blackish at 
base and black at the stigma but not thickened there. Hind wings 
with all the veins hyaline. Length to tip of wings .10-13 inch. 
The antennae scarcely attain the base of the 1st discoidal ot the 
expanded wing, and the stigma is about three times as long as wide 
and very acutely pointed at its basal end. Forms near the middle 
of the midrib of the leaf of the cotton-wood ( Populus angulata ) what 
appears above as a smooth, green, semicircular, compressed gall ; crowned 
by the midrib and from one quarter to two filths of an inch long, 
but which below is entirely open, the sides of the leaf bending^ down 
together so as to touch each other and conceal the opening. Lhe in¬ 
sects oten wander from this false gall and associate with Aphis popu- 
lifoliae Fitch. Comes very near popularia Fitch, (the gall of which 
is unknown) but that species has the discoidals “blackish” and the 
“antennae only two-thirds the distance to the wing-sockets.” Differs 
from populi ylobuli and populivenae Fitch in the sub-costal not being 
thickened at the stigma and also in the peculiar structure of its gal!. 
The recent larva is densely covered with white pruinescence, on re¬ 
moving which it is yellowish, with only the eyes and tarsi blackish, 
and the disk of the abdomen freckled with reddish (V alsh). 
Pemphigus vagabundus. Walsh. The Vagabond Gall-louse. 
«■ 
Syn. * Byrsocrypta vayabunda Walsh. 
This species produces a rather large, irregular gall on the tips of 
of the twigs of certain cotton-woods, and also occasionally on balsam 
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