CANKERWORMS SNODGRASS 



321 



Fig. 4.- — Female inotli of spring eaukerworm deix)sit- 

 Ing eggs in crevice beneath piece of loose bark 



most clusters found on the trees indicates that they must have been 

 placed in this same manner. Others, however, are deposited so far 

 under a ledge of bark that the moth must have entered the cavity in 

 order to have reached its innermost recesses with her egg tube. Her 

 habit of probing forward suggests that in such cases she backs over 

 the edge of the piece of loose bark and enters the cavity upside down. 

 The purpose of the spines on her back is not evident. Though they 

 may protect her body in 

 tight places, it would 

 seem that they would 

 also impede her en- 

 trance into crevices. 

 The spines are present 

 likewise on the same 

 segments in the male, 

 but are somewhat w^eak- 

 er than in the female. 



The eggs of the 

 spring canker worm (fig. 

 5) are to be found on 

 the trunk, on the limbs, 

 and on the twigs of the trees. Usually they occur in groups of 

 30 to 60, though as many as 150 have been recorded in one mass, 

 and often there are but three or four together. Dr. S. J. Hunter, 

 writing of the spring cankerworm in Kansas, says that a dissection 

 of 12 moths gave an average of 401 eggs in each, an exceptional in- 

 dividual containing 676 eggs. A count of the actual number of eggs 

 laid, however, he says gave an average of only 81 for each moth, 



but these records were made from moths 

 of a brood below normal vitality. The 

 eggs of the spring cankerworm are oval 

 in shape, rounded at one end, slightly 

 pointed at the other, and are about one 

 thirty-sixth of an inch in length. The 

 shells are soft, easily dented, and are 

 marked by fine lengthwise lines; those of 

 some groups are brownish, others are 

 greenish, but all are iridescent with pink and green reflections. 

 The eggs lie in jumbled masses, all stuck to the bark or to one an- 

 other, some flat on their sides, others inclined or standing on end. 



When the moth has deposited her eggs her brief life's work is 

 over. She falls back to the earth and there lies until her vital forces 

 are dissipated. Yet the eggs within her egg tubes previous to lay- 

 ing had no connection with her body ; being freed from their weight, 

 it would seem, should be a relief to her and not an exhaustion. Here 



Fig. 5. — Group of eggs of 

 spring cankerworm moth 

 beneath projecting piece 

 of bark (much enlarged) 



