66 THE SCIENCE OF DRY FLY FISHING. 



The following are some of the well-known forms of the 

 Ephemeridae : Olive Duns, Duns, Blue Duns, Autumn 

 Duns, Blue Winged Olives, Iron Blue Duns, Red Quill 

 Duns, Red Spinner, Jenner Spinner, May Fly, March 

 Brown, etc. 



THE TRICHOPTERA, OR CADDIS FLY. 



These insects, unlike those of the Ephemeridae and 

 Perlidae family, undergo a distinct metamorphosis during 

 their sub-aqueous existence. 



The larvae of the Caddis Fly may be divided into two 

 distinct classes. The one class, after leaving its egg, spins 

 a cylindrical case for its future home, to which it attaches 

 small stones, sand, wood, etc. ; these cover and mask this 

 case, form an armour-like protection against enemies, and 

 at the same time act as ballast. The larva uses this tube 

 as a movable residence, and from the open end its head, 

 thorax, and legs protrude and provide the motive power, the 

 weak and maggot-like body being always enclosed and 

 protected by the armour-clad case which it drags about 

 from place to place. After various enlargements to suit the 

 growing condition of its body, the larva enters and partially 

 closes the open end of its case ; it then commences its pupal 

 existence, i.e., it becomes a chrysalis, and finally tears open 

 the sac covering which has protected it during the dormant 

 existence. Swimming to the surface, it either supports itself 



