FIELD BOOK OF PONDS AND STREAMS 



Members of the subfamily RhyacophilincB, represented here 

 by Rhyacophila (Fig. 190), do not make cases until they are 

 full grown and ready to pupate when they wall themselves 

 in loosely and spin a parchment-like cocoon. In the other 

 subfamily, Glossosomatince, the larvae make cases of which the 

 turtle-shaped Glossosoma (Fig. 191) is a type. 



Fig. 190. — Caddis worm, Rhyacophila. 



Rhyacophila. — This larva creeps about naked on the under 

 surfaces of stones in riffles until it is fullgrown. It then 

 enters a crevice between them and walls itself into a chamber 

 much larger than itself, by fastening the pebbles together 

 with its own saliva. Here it spins a brownish, parchment - 

 like cocoon within which it transforms (Fig. 190). The adults 

 emerge from late May to the middle of July, probably all 

 summer. Length of fullgrown larva, one half inch. 



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Fig. 191. — The turtle-shaped case of Glossosoma 

 americana: I, upper and 2, under side. (After 

 Lloyd.) 



Glossosoma americana. — These larvse build turtle-shaped 

 cases of pebbles and sand grains (Fig. 191). They live singly 



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