74 ‘ FISHING GOSSIP. 
this state the larve of the Phryganide 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; Reaumur 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 Phryganide. Thus the 
pupa of the Phryganea 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- 
