94 OUR INSECT FRIENDS AND FOES 



the veritable "old-clo' men" of the ponds and 

 streams. They are long, more or less cylindri- 

 cal insects, with only the head, thorax, and legs 

 horny, the rest of the body being quite soft, 

 and it is the necessity of hiding their sleek and 

 tempting bodies from their numerous hungry 

 foes that has made the Caddis-worms adopt the 

 " old-clo' " habit and manufacture out of the most 

 varied materials the curious cases with which 

 they clothe themselves. Tiny pieces of wood, 

 small twigs, bits of leaves, small stones and 

 grains of sand, and minute shells often still con- 

 taining their living owners, are all pressed into 

 service of the Caddis larva for the purpose of 

 making its body-case; while a little careful 

 observation will reveal the interesting fact that 

 each species of Caddis affects some particular 

 class of material for the construction of its case. 

 Nor are all alike in their habits, some living in 

 fixed cases at one spot, while others wander 

 about freely at the bottom of the pond or stream 

 by protruding the head and first two thoracic 

 segments beyond the mouth of the case, and 

 crawling, or half swimming, by means of the two 

 front pairs of slender legs attached to the thorax. 

 The third pair of legs are frequently tucked 

 away inside the case, so as to help the insect to 

 rapidly withdraw into its shelter. The larva has 

 also on the apex of the abdomen certain hook- 

 like appendages, which enable it to grip the 

 interior of its case. 



The cases, formed from such varied materials, 

 give the Caddis larvae a very curious appearance, 

 and make their movements far from graceful, 



