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SCHOOL ENTOMOLOGY 



worms " and are the larvae of two nearly related species of 

 moths, very similar both in appearance and habits. The 

 spring canker worm is so-called because its eggs are laid by 

 the females in March and April and hatch a month later, 

 while the fall canker worms hatch about the same tune from 



eggs laid the previous Novem- 

 ber or December. The female 

 moths are wingless and look 

 much more like spiders than 

 ordinary moths. The male 

 moths have delicate wings of 

 a dark gray color, expanding 

 about an inch. The fore 

 wings of the spring canker 

 worm male are crossed with 



three rather indistinct darker lines, while those of the fall can- 

 ker worm are crossed by two whitish bands. The young cater- 

 pillars commence to feed on the leaves just as they are 

 expanding, and if abundant will soon devour all but the mid- 

 ribs. They have a habit of dropping from the trees and 



FIG. 224. The spring canker 

 worm (Paleacrita vernata). 



a, male moth; b, female moth 

 both natural size. 



FIG. 225. Eggs of spring canker worm twice natural size. 

 (After W. E. Britton.) 



hanging suspended on strands of silk. They become full 

 grown in four or five weeks and are then about an inch long, 

 slender, cylindrical, varying from ash-gray to green or yellow, 

 but mostly dark greenish-olive or blackish, marked with 

 narrow pale lines down the back and a whitish stripe along 



