MOTHS OF THE LIMBERLOST 



of the others. Lengthwise of a slender twig it spins a 

 long, slim cocoon; on a board or wall, roomier and wider 

 at the bottom, and inside hollow trees, and under bridges, 

 big baggy quarters of exquisite reddish tan colours that 

 do not fade as do those exposed to the weather. The 

 typical cocoon of the species is that spun on a fence or 

 outbuilding, not the slender work on the alders or the 

 elaborate quarters of the bridge. On a board the process 

 is to cover the space required with a fine spinning that 

 glues firmly to the wood. Then the worker takes a firm 

 grip with the anal props and lateral feet and begins 

 drawing out long threads that start at the top, reach 

 down one side, across the bottom and back to the top 

 again, where each thread is cut and another begun. 

 As long as the caterpillar can be seen through its work, 

 it remains in the same position and throws the head back 

 and around to carry the threads. I never thought of 

 counting these movements while watching a working 

 spinner, but some one who has, estimates that Poly- 

 phemus, that spins a cocoon not one fourth the size 

 of Cecropia, moves the head a quarter of a million times 

 in guiding the silk thread. When a thin webbing is 

 spun and securely attached all around the edges it is 

 pushed out in the middle and gummed all over the 

 inside with a liquid glue that oozes through, coalesces 

 and hardens in a waterproof covering. Then a big nest 

 of crinkly silk threads averaging from three to four inches 



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