MAY-FLIES AND THEIR NEIGHBOURS 227 



of their own cases until they were completely en- 

 cased in a new tube, they occupied just about three 

 hours : which, considering that they had no choice 



Fig. 151. A large dragon-fly. 



of material other than that provided, appeared to 

 me to be rather smart work. 



To remove a caddis-worm from its case is no 

 easy matter, and if I refer my reader to Fig. 150, 

 where is shown a magnified view of the latter end 

 of the body of a caddis-grub, showing the horny 

 hooks by means of which it retains hold of its 



