446 NATURAL HISTORY OF ARTHROPODS. 



throughout the northern portions of the United States and Canada. The fore wings 

 of the male moth expand two inches or more, and are of a dull yellowish color 

 sprinkled with brown, with two brown lines across them, and a brown dot on the end 

 of the cell. The portion of the wing beyond the outer line is usually somewhat 

 darker. The hind wings are much paler, sprinkled with brownish, with a dot on the 

 end of the cell, of the same color. The female is wingless, yellowish white, sprinkled 

 Avith black along the sides, with two black spots on the top of each segment, except 

 the last, which has but one. The eggs are laid in the autumn, in clusters, on the 

 branches of trees. They are oval, of a pale yellow color, and covered with a net- 

 work of raised lines. They hatch early in the spring, and feed on the leaves of 

 apple, basswood, elm, and hickory. 



Two distinct species of geometrid moths are known as canker-worms; and since 

 they resemble each other both in appearance and habits, it is not surprising that they 

 have been included under one common name. The males have well-developed wings, 

 but the females are wingless. 



Anisopteryx pometaria, sometimes called the fall canker-worm, emerges from 

 the ground late in the fall, even after quite heavy frosts, and ascends the trunks of 

 trees. The females deposit a hundred or more dull whitish eggs, in a cluster, exposed 

 on the twigs or branches. These eggs are flower-pot shaped, attached by the smaller 

 end ; and the larger, or exposed end, has a central depression and a dark ring near the 

 outer edge. It sometimes occurs that the females crawl up on the side of buildings, 

 and deposit their clusters of eggs far from the trees or any suitable food for the cater- 

 pillars. The eggs hatch the following spring, at the time the young leaves begin to un- 

 fold. The mature caterpillar is about an inch long, with only three pairs of abdominal 

 legs. They vary in color, from greenish yellow to dusky or dark brown, with broad 

 yellowish or pale stripes along each side. When not feeding they take a rigid position, 

 either along the twig on which they rest or at an angle of about forty-five degrees, 

 resembling, both in color and position, a dead twig, and thus avoid detection. After 

 they are done feeding they descend to the ground, either on the trunk of the tree or 

 by means of a thread which they spin, and burrow to the depth of several inches, 

 where they spin their buff-colored cocoons of silk mixed with particles of earth. 

 They remain in the pupa state, in the ground, during the rest of the summer, and the 

 perfect moths emerge late in the fall, as stated above. 



The males, which expand nearly an inch and a half, have brownish gray fore wings, 

 crossed by two irregular whitish bands, the outer one of which enlarges on the costa, 

 forming a whitish spot. The hind wings are grayish brown, with a blackish dot near 

 the middle, and an indistinct band crossing beyond. The female is ash gray, a little 

 more than a third of an inch long ; and the abdomen is greatly distended with eggs, 

 giving the insect a broadly oval outline. The antennae are simple. 



A. vernata, usually called the spring canker-worm, emerges from the ground in 

 the spring, though a few make their appearance in the fall. The wingless females 

 ascend the trees and deposit their pearly, oval shaped eggs in crevices of the bark, 

 to the number of a hundred or more. These eggs hatch at about the same time as 

 those of A. pometaria, and the mature caterpillar closely resembles that of the other 

 species, but has only two pairs of abdominal legs. They are also similar in their habits, 

 and descend into the ground at the same time, but form a more fragile cocoon. The 

 male moth, which expands about an inch and a quarter, has ash colored or brownish 

 gray fore wings, with a silky lustre. A broken whitish band crosses the wing, near the 



