

E. 



^« 



\. 



D. 



A. 



c. ,, 



-^-s (. f '' f 





t^ 



A. Home of tin Nit-hiiildiiiv Caddis Jlr. B. House made of hollow 

 seeiion of stiek. C. Made of snail slielh. D. Home of pebbles. B. 

 Composed of st razes. 



SincL- these worm-like creritures are in reality larvae, 

 they must enter the dormant or pupal state before be- 

 coming a full-fledged fly. ^^'hl■n ready to change, the 

 larvae blocks up the entrance to the home with a ])ebble, 

 leaving sufficient space for a circulation of water, or it 

 may weave a gauze web across the entrance. 



As soon as the newly developed insect leaves the pupal 

 case it swims rapidly to the surface, using its middle pair 

 of legs as oars. Its wings are folded in little packets on 

 each side of the bodv but instantly upon coming into 

 contact with the air, tliey expand to their normal size and 

 away flies the fully developed caddis-fly, Comstock esti- 



