FIELD BOOK OF PONDS AND STREAMS 



Family Limnophilidae. — The caddis worms of this family are 

 most abundant in ponds and slow-moving streams. The 

 cases of different species are made from a great variety of 

 materials and sometimes the young and old larvae make very 

 different cases. 



Fig. 198. — Case of Limnophilus combinattis. 



Limnophilus combinatus. — When they are young the larvae 

 make cases of the log cabin type, but when they mature they 

 migrate away from the grassy shorelines and gather their 

 building materials from the bottom, using bark and seeds. 

 When little mollusks are available the case may be made 

 almost entirely of Planorbis (Fig. 251), and SphcErium (Fig. 

 266) shells with their occupants often still alive; such cases 

 are about three quarters of an inch long. 



Family Sericostomatidae. — These are caterpillar-like larvae 

 w^hich are found in both streams and lakes. 



Helicopsyche. — The little Helicopsyche cases (Fig. 199) are 

 good examples of objects which may be in abundance before 

 our eyes yet altogether undiscovered. Helicopsyche lar^^as 

 are rarely seen when they are creeping over the sandy bottom, 

 only becoming known when the fullgrown larvae cluster by 

 dozens upon the rocks and fasten their snail-shaped cases 

 down tightly to them in preparation for the pupal change. 

 They weave silken lids over the openings of the pupal cases; 

 these can be seen with a hand-lens. The adults emerge in 

 June and July. 



Cases less than a quarter of an inch wide. 



Goera. — The larvae of Goer a can be found on current-swept 

 rocks from late summer till the end of March. Their cases 



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