224 MINUTE MARVELS OF NATURE 



species will often use a variety of substances 

 which happen to be near at hand. Fig- J 49 



Fig. 149. Specimens of the cases built by caddis-worms. 

 Natural size 



shows a number of these cases made of various 

 substances and in many forms. The first is built 

 of water-logged bits of stick cut to suitable sizes 



