74 FISHIXG GOSSIP. 



this state the larvce of the Phryganidae are the cadis, 

 case-worms, or cad-bait of our old writers on angling. 

 But, as the venerable Walton says, " to know these 

 and their several kinds, and to know to what flies 

 every particular cadis turns, and then how to use 

 them, first as they be cadis, and after as they be flies, 

 is an art, and an art that every one that professes to 

 be an angler has not leisure to search over." 



When the period arrives for the larva to assume 

 the pupa state, it securely anchors itself to the bottom, 

 and closes up the mouth of its case with a network 

 of strong silk, leaving but a few apertures to admit a 

 current of fresh water for the purpose of breathing, 

 effected by the spiracles of the pupa ; Eeaumur having 

 actually observed this network in motion, alternating 

 from concave to convex, as the water passed out and 

 in. After passing its due time in this state, the 

 pupa, endowed with greater powers of motion than 

 are possessed by any other incomplete pupa, with its 

 stony mandibles cuts its way through the network, 

 and leaving its case, throws off a filmy skin and 

 becomes a fly. There are slight differences in the 

 transformations of the many Phryganidae. Thus the 

 pupa of the Pliryganea grandis, the stone-fly of fisher- 

 men, leaving its case makes its way to the shore, and 

 lives several days in an incomplete state before it 

 becomes a fly. In this state it is the water-cricket 

 or creeper of the north of England and Scottish fisher- 



