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ANNUAL REPORT SMITHSONIAN INSTITUTION, 1924 



moving the legs and for enabling these members to drag the heavily 

 loaded body over the ground and up the tree, and of course there are 

 breathing tubes, nerves, and a heart, all of which organs are neces- 

 sary for existence. But the alimentary canal is reduced to a mere 

 thread, and the external organs for taking food are so rudimentary as 

 to be entirely useless, the material necessary for maintaining the life 

 of the moth and for maturing the eggs having l)een stored in the 

 body of the insect during her own caterpillar days. 



The exterior of the body of the moth appears to be covered with a 

 thick coat of fur, but, as with all moths, the material is really a 

 close growth of slender scales, which, however, are but modified hairs. 

 On the back of each of the seven exposed segments of the abdomen 

 there are two crosswise rows of recumbent spines directed backward. 



From the rear end of the body the 

 spring cankerworm moth can protrude 

 a long tapering tube made of the ter- 

 minal body segments, which are ordi- 

 narily retracted one into the other like 

 the sections of a telescope. The eggs 

 are extruded from the end of the tube 

 when the tube is extended. 



For a long period, sometimes for 

 several days, the female moth sits on 

 the trunk or on a lower limb of the 

 tree quietly waiting, perhaps not knoAV- 

 ing why, but events suggest that she 

 is waiting for a mate. At any rate, 

 a male moth (fig. 3) eventually comes 

 to her; he comes fluttering on large 

 wings, for in respect to organs of flight 

 he has not lost his insect heritage, though he too lacks organs for 

 taking food. After a brief time of courtship and mating the male 

 departs, and the deserted female is left to finish her life in solitude 

 as she began it. But now, in addition to her eggs, she carries 

 the fertilizing element of the male, without which the eggs would be 

 useless. The female soon resumes her journey upward and outward 

 on the branches of the tree, searching for suitable places at which 

 to deposit her eggs. 



When the egg-laying tube of the female is fully extruded it is 

 about as long as half the rest of the body. With its tip the moth 

 probes into crevices or beneath pieces of loose bark, and when an ap- 

 propriate place is located she deposits there a group of eggs (fig. 4). 

 Moths that were taken into a room for observation during egg laying 

 curved the egg tube forward beneath the body and ejected the eggs 

 forward and downward from its tip ; and the position of the eggs in 



Fig. 3. — Male moth of spring 

 cankerworm (X 2%) 



