The Caddis- Worm 



lengthens, tapers and ends by wrapping the 

 animal in a light and floating drapery. 



Thus clad for the time being, either in the 

 fine silk of the pond-weed or in the linsey- 

 woolsey supplied by the roots of the water- 

 cress, the Caddis-worm begins to think of 

 building a more solid sheath. The present 

 casing will serve as a foundation for the 

 stronger building. But the necessary ma- 

 terials are seldom near at hand: you have to 

 go and fetch them, you have to move your 

 position, an effort which has been avoided un- 

 til now. With this object, the Caddis-worm 

 cuts its moorings, that is to say, the rootlets 

 which keep the cylinder fixed, or else the half- 

 severed leaf of pond-weed on which the cone- 

 shaped bag has come into being. 



The worm is now free. The smallness of 

 the artificial pond, the tumbler, soon brings 

 it into touch with what it is seeking. This 

 is a little faggot of dry twigs, which I have 

 selected of equal length and of slight thick- 

 ness. Displaying greater care than it did 

 when treating the slender roots, the carpenter 

 measures out the requisite length on the joist. 

 The distance to which it has to extend its body 

 in order to reach the point where the break 



195 



