THE CANKER-WORM 



largely localized, an orchard here and there showing by the 

 browning of the foliage the presence of the enemy, while 

 neighboring orchards and isolated trees remain- uninjured. 



THE LIFE-HISTORY OF THE CANKER-WORM 



In regions where the canker-worm is present in destructive 

 numbers one will sometimes see orchards which in June appear 

 seared and brown as if scorched by fire. Closer examination 

 will show that the green portions of the upper surfaces of the 

 leaves have been eaten off, so that there remain only the veins 

 and more or less of the withered under surface. Had you 

 observed the trees during May you would have found myriads 

 of looping caterpillars each busily feeding upon the succulent 

 tissues. These canker-worms are green or brown, more or 

 less striped with longitudinal lines. Just back of the head are 

 six legs with pointed claws, and near the posterior end of the 

 body are four or six other legs, different in form. When the 

 caterpillar crawls the middle of the body assumes the shape of 

 a hump or loop ; on account of this these insects are called loop- 

 ing caterpillars or measuring worms. If the twig upon which 

 they are stationed is jarred, each caterpillar drops earthward, 

 spinning from its mouth a silken thread, which prevents too 

 sudden a descent to the earth below. 



Early in summer, the canker-worms become full-grown in 

 the larval state. They then enter the soil two or three inches, 

 sometimes simply seeking the shelter of the rubbish upon its 

 surface, where, protected by silken cocoons in cells, they 

 change to pupae. There they remain until autumn or the fol- 

 lowing spring, when the moths emerge. In these, the sexes 

 are strangely different ; the males are small of body and large 

 of wing, well adapted to easy fliglit ; while the females are 

 large of body, and wholly destitute of wings. The latter are 

 thus doomed to pass the short remainder of their lives in the 

 vicinity of their emergence. They crawl up the trunks of 

 neighboring trees, where upon the twigs they deposit their 

 eggs, dying soon afterwards. When the leaves appear, burst- 

 ing through the buds, the eggs hatch into the young caterpillars, 

 that feed upon the tender foliage. 



