NATURE'S CRAFTSMEN 



sand and the palpitation of the chip showed that it was 

 at work underneath. At times it would reappear, to 

 add to or strengthen its outer wall. Often it would 

 thrust out the fore part of the body alone, and move it 



PUPAL CASE OF A NET-MAKING CADDIS WORM, 

 OPENED TO SHOW DEAD PUPA WITHIN 



about, weaving threads to tie or cement together the 

 sand grains with which it was building. Meanwhile it 

 seemed to be anchored by its anal hooks to some point 

 within. 



Having thus been permitted to uncover the secrets 

 of its craft, I was loath to disturb the little craftsman 

 and destroy its work. But hardening my heart "in 

 the interest of science," I lifted up the brown, water- 

 logged chip which had been the background of the 

 larva's operations. Down fell the wee protecting wall 

 of threaded sand pellets. The builder wriggled its pro- 

 test and fled; and, as expected, there appeared a tubu- 

 lar space which had been cleared away by pushing and 

 packing the sand to either side. This was meant to be 

 the refuge and home den, and in due time would have 

 been hung and carpeted with silken tapestry, and so 



280 



