200 CAD-CASES PIPER CADDIS. 



of straw, rush, loose particles of sand and fine gravel, 

 which they contrive in a very wonderful manner to 

 cement together into cylindrical tubes by means of a 

 glutinous secretion which exudes from their bodies for 

 the purpose, in order to afford them protection during 

 this helpless stage of their existence. Many of the 

 cases of the smaller species are composed of particles 

 of quartz sand, most artistically arranged so as to fit 

 accurately to each other, and with the smooth facets 

 towards the interior ; and when viewed through a 

 magnifying lens, the beautifully disposed different- 

 coloured crystals present no mean imitation of an 

 elaborate piece of mosaic work ; while the interior of 

 the tube is smooth and polished as glass, and lined by 

 a coating of the same glutinous cement which holds the 

 particles of sand together. Multitudes of these larvae, of 

 different species and sizes, and encrusted with various 

 substances, may be found adhering to stones and stumps, 

 or crawling about the bottom of every little rill and 

 pool in the vicinity of a river, like animated pieces of 

 straw, the head and fore -legs alone protruding from 

 the orifices of their unique habitations. 



The Piper Caddis, so called from the shape and ma- 

 terial of which its case is composed, is the larva of the 

 stone-fly, and the largest of the tribe ; being about an inch 

 in length, and forms one of the best angling baits among 

 the caddies. This larva is very common in northern 

 and Welsh streams, as well as the fly which produces 

 it ; and is said never to be found but where the bed of 

 the river is either composed of limestone or large 



