CANKER WORMS. I23 



have a broad, dark stripe along the back, as opposed to the 

 narrow markings of the other species. The eggs, which are 

 slightly larger than in the previous species, somewhat resemble 

 small flower pots and are attached to the bark, in exposed situ- 

 ations, in masses of from 60 to 200, placed side by side as seen 

 in figure 40, e. The eggs highly magnified, are shown in 

 figure 40 a and 40 b. 



The eggs are deposited in fall 

 or early winter (sometimes in mild 

 winters as late as March). They 

 hatch about the same time as those 

 of the other species and the larvas 

 act in a similar manner, entering 

 the ground about the same time. 



Instead of forming a cell lined with piguTe 40 -Fail canker worm; a. and 



silk however this snecies snins a <^. eggs, enlarged; c. segment of larva 

 SUK, nowcver, iniJ, bpcciCb bpnib a, enlarged; «. egg cluster;/, full grown 



tough cocoon, and the moths come '*'■^^■ 



forth and begin laying eggs in October and November. 



HOW TO FIGHT CANKER-WORMS. 



The natural enemies of the canker-worms, including 

 Ichneumon, Tachina and Chalcid flies, certain wasps and 

 beetles, and various kinds of birds, are so numerous as to 

 prevent serious damage save in exceptional years. In the 

 absence of these natural enemies, however, or when the weather 

 conditions are specially favorable to the increase of the worms, 

 active measures must be taken to save the trees. 



One of the surest preventive measures is to place a band 

 of tarred paper about the tree in March and smear it with 

 printers' ink, thus preventing the ascent of the female moths 

 and the deposit of eggs. In case the bark is very rough, it 

 should be scraped smooth to prevent the insects from crawling 

 up behind the paper. The ink must be renewed often enough 

 to prevent hardening, or it will be of no use. If the fall 

 canker-worm is present, of course the treatment must begin in 

 October. If the trees are already attacked, jarring the limbs 

 will cause many of the worms to spin a thread and drop to the 

 ground. If the band of printers' ink is in place they will be 

 unable to return to the attack and may be destroyed. 



