INSECTS AFFECTING PARK AND WOODLAND TREES l8q 



Spruce gall aphid 



Cher Dies abictis Linn. 



Somewhat cone-sliaiied, many-celled galls are forineil at the bases of vomit; spruce 

 shoots; later these dry, turn brown antl open, thus allowint; the inclosed ])lant lice to 

 escape. 



This specii's has bcL-n observed l)y us on spruce in Albany, and il also 

 occurs in other parts of the State. It is, according" to Professor Coolev, 

 widely distributed in America, since it has been met with in New Enijland, 

 recorded by him from Canada, occurs as far west as Washing-ton, and has 

 been recei\'ed from a nimiber of intervening localities. 



Description. The gall is a somewhat conelike, many-celled structure 

 about 3/j[ inch in length. It is at first entirely green or more or less rosy in 

 color, taking on a yellowish tinge in August, at which time the cavities 

 open slowly and the gall begins to dry up and turn brown. 



The eggs are deposited in small clusters, each attached to a leaf by a 

 slender stem. They are ellipsoidal in form, about ' 60 inch in length, light 

 yellow when deposited, gradually turning darker. The newly hatched 

 young measure about ' 60 inch in length, are oval, tapering slightly toward 

 the posterior end. The full grown young are about ' ,2 inch long, with the 

 head, thorax and all the appendages yellow, the abdomen rather reddish 

 and the wing pads tinged with green in man\' indi\"iduals, though in some 

 they are light brown. The winged female is from abotit '8 to '^10 inch in 

 length, with a wing e.xpanse of about ' , inch. Recently emerged individu- 

 als are a nearly uniform yellowish color, but with age darker mai"kings 

 become apparent and the head and thorax are then a nearly uniform deep 

 brown, while the abdomen retains its yellowish color, the fore wings with 

 the stigma and costal cell are distinctly green. The posterior end of the 

 thorax is covered with a white, tlocculent secretion, which extends along 

 the sides of the abdomen toward the thorax. The young of the winter 

 generation measure about ■ 60 inch in length. The dorsum of the head and 

 thorax and the spots on the dorsum of the abdomen are brown ; the 

 remainder of the body is yellowish brown. 



