152 
poplars, which somewhat resemble the flower of the double cocks¬ 
comb of our gardens. These galls turn black in winter, giving the 
Fig-. 27. 
Gall of Pemphigus vagabundus. 
tree a singular and rather unsightly appearance after the leaves have 
fallen off. The winged insect generally makes its appearance in 
September; (Vagabond Gall-louse. Fig. 25) the body is black, and 
about one tenth of an inch long; the expanded wings measure rather 
more than one-third of an inch from tip to tip; antennae six-jointed. 
The name vagabundus , or vagabond, has been given to it on acount 
of its habit bf wandering to a great distance from its place of birth. 
It is possible as has been sugges'cd, that Dr. Fitch’s winged specimens, 
described as P. pyri , belonged to this species. 
The original description by Mr. Walsh, is as follows: “Black, 
polished, with no app>earance of pwuinescence. Antennae and legs 
dull fuscous. Abdomen and venter obscure opaque yellowish, varied 
with fuscous or sometimes with brown. Wings subhyaline with a 
whitish tinge, costal and subcostal veins, and one-third of the inner 
edge of the wing from the tip of the first discoidal to the base of 
the wings, conspicuously fuscous; the remaining veins in both wings 
whitish hyaline; costal slightly tinged with brown, stigma pale 
fuscous brown, its interior vein thickened. Alar expanse .43—51 inch/’ 
“Sixth joint of the antenna is two thirds as long as fourth and fifth 
put together; and the stigma is 3-^ times as long as wide, very acutely 
pointed at both ends. There are four specimens which have a little white 
pruinescence still attached to their wings. Occurs very abundantly 
on various forest trees in September.” 
Pemphigus riiois. Fitch. The Sumac Gall Plant-louse. 
This species forms tomato-shaped galls on the leaves of different 
kinds of sumac, which usually arise from the mid-vein at or near the 
