V CADDIS-WORMS 253 



proceeding. This time I put it into a saucer of white 

 earthenware, half full of water, taking care to throw 

 in bits of straw, hay and wood. For nearly three- 

 quarters of an hour the larva crept about feeling the 

 sticks and straws without deciding how to make use 

 of them. They did not appear suitable to the work 

 in hand. Perhaps they were too light, for they were 

 not yet perfectly soaked in water. Then I broke up 

 the two sheaths from which the larva had been 

 successively expelled, and threw them into the w^ater. 

 Some of the fragments floated while others sank to 

 the bottom. I threw in also bits of leaves, and it was 

 not long before the Caddis-worm had found what it 

 wanted. It fixed upon a fragment of leaf nearly as 

 long as itself, and much broader. The hinder part of 

 the body moved up and down so that the bunches 

 of filaments carried upon it were seen to wave to and 

 fro. While this was going on, the head was busily 

 employed. The larva cut off bits of the leaf, and 

 passed its head to and fro between them, as if in the 

 act of spinning, and very shortly the pieces were 

 fastened together. Thus the work went on until in 

 a short time the sheath concealed the fore part of the 

 body. It gradually grew until the whole body was 

 covered, but so far the work was very rough, and 

 spaces could be seen between the fragments. The 

 sheath was moreover too large for the body, and 

 accordingly several pieces were slipped inside and 

 fastened down one after another. There happened 

 to be in the saucer a branch of a water plant with 

 nearly cylindrical leaves of about the dimensions of 

 a common pin. The Caddis-worm cut several bits 



