THE MAY-FLY AND THE CADDIS-FLY. 



631 



single day sometimes witnessing its entrance into the perfect state and 

 its final departure from the world. The popular idea concerning these 

 insects is that the whole of their life is restricted to a single day. This, 

 however, is an error, as they have already passed at least two years in 

 their preliminary stages of existence. In the larval and pupal states 

 they are inhabitants of the water, and are fond 

 of hiding themselves under stones or burrow- 

 ing into the muddy banks. Under the latter 

 circumstances they make a very curious tun- 

 nel, something like a double-barrelled gun. 



The May-fly is peculiarly notable for a stage 

 of development which seems to be quite unique 

 among insects. When it has passed through 

 its larval and pupal state it leaves the water, 

 creeps out of its pupa-case, and takes to its 

 wings. After a period varying from one to 

 twenty hours it flies to some object, such as 

 the trunk of a tree or the stems of water- 

 plants, and casts ofi" a thin membranous pel- 

 licle, which has enveloped the body and wing, 

 the dry pellicle remaining in the same spot, 

 and looking at first like a dead insect. After 

 this operation the wings become brighter, and 

 the three filaments of the tail increase to twice 

 their length. Some authors call the state be- 

 tween leaving the water and casting the pel- 

 licle the " pseudimago " state. 



Some of these insects are well known to fish- The May-fj.y {Ephemera 

 ermen under the names of Green and Gray vugaa). 



Drake, the former being the pseudimago, and the latter the perfect 

 form of the insect. Sometimes these insects occur in countless myr- 

 iads, looking like a heavy fall of snow as they are blown by the breeze, 

 and having on some occasions been so plentiful that they have been 

 gathered into heaps and carted ofl" to the fields for manure. 



The order called Trichoptera, or Hairy-winged Insects, is represented 

 by the common Caddis-fly. 



This fly is well known to every angler both in its larval and in its 

 perfect state. The larva is a soft white worm, of which fishes are ex- 

 ceedingly fond, and it therefore requires some means of defence. It 

 accordingly actually makes for itself a movable house of sand, small 

 stones, straws, bits of shells, or even small living shells, in which it 

 lives in perfect security, and crawls about in search of food, dragging 

 its house after it. When it. is about to become a pupa it spins a strong 

 silk grating over the entrance of its case, so that the water necessary 



