STATE HORTICULTURAL SOCIETY. 197 



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 o.ii 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, according to 

 Dr. Fitch, are females, which produce eggs of a dull wax color, the eyes 

 of the inclosed larva appearing like two black dots near one end. These 

 eggs hatch in a kw moments after they are deposited. These so-called 

 eggs, by Dr. Fitch, are doubtless the thin egg-like sacks we have hereto- 

 fore mentioned, in which the larvae are inclosed; hence, this method of 

 reproduction must properly be classed as viviparous, or, perhaps more 

 correctly, ovi-viviparous. 



80. Pemphigus populi-ve7i(2, 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 situated 

 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 semicircular, and half as high as they are long, being usually 

 over half an inch in length, with an uneven surface, their walls thick and 

 brittle. 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 larvas are 

 much less numerous than the females, and are double their size ; are pale 

 dull green, with whitish antenna; 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 being usually 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 ; liead dark ; legs dull yellow, and feet dusky. 



The winged individuals black, with coarse thread-like antennie, 

 reaching to the base of the wings. The wings are pellucid and colorless, 

 as are the oblique or discoidal veins; the rib-vein blackish, coarse and 

 somewhat enlarged along the inner margin of the stigma; marginal vein 

 blackish. Length to the tip of the abdomen, 0.05 inch ; to the tips of the 

 wings, 0.08 inch. 



81. Pe7nphigus hamamelidis. Fitch. The Witch Hazel Gall-louse. 



Inhabits conical follicles on the upper surface of witch hazel leaves; 

 each follicle contains about a dozen individuals, and has a small orifice 

 on the under surface of the leaf. 



