INSECTS AFFECTING PARK AND WOODLAND TREES 1 89 



Spruce gall aphid 



Chcniiis abictis Linn. 

 Somewliat cone-shaped, many-relied galls are formed at the bases of yomii:,' spruce 

 shoots; later these dry, turn brown and open, thus allowing the inclosed plant lice to 

 escape. 



This species has been observed b)- us on spruce in Albany, and it also 

 occiu's in other parts of the State. It is, according; to I'rofcssor Cooley, 

 widely distriljiited in America, since it has been met with in New Eno;land, 

 recorded by him from Canada, occiu's as far west as W'ashini^ton, and has 

 been received from a munber of intervening- localities. 



Description. The yall is a somewhat conelike, luany-celled structure 

 about -^4 inch in leni^th. It is at first entirely green or more or less rosy in 

 color, taking on a yellowish tinge in .\ugust, at which time the cavities 

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



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

 slender stem. They are ellipsoidal in form, about ■ ,„, inch in length, light 

 yellow when deposited, gradually turning darker. The newly hatched 

 young measure about ■ ,„_, inch in length, are oval, ta[)ering 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\- individuals, though in some 

 the)' are light brown. The winged iemale is from aliout 's to ', i,, inch in 

 length, with a wing expanse of about ' ^ inch. Recently emerged individu- 

 als are a nearly uniform yellowish color, but with age darker markings 

 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 distinctlv 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 arc brown ; the 

 remainder of the body is yellowish brown. 



