TRICHOPTERA : CADDICE-WORMS. 



in time to catch unwary flies; but the small (less than .25 

 in. long) species of Boreus, which have no wings and are 

 found on the snow in the Northern States, must find poor 

 picking there. 



TRICHOPTERA 



These insects have an incidental interest in being near 

 to the ancestors of butterflies and moths, but they need 

 no reflected glory to give them an appeal. They have 

 complete metamorphosis, and, although the adults are 

 aerial, the larvas and pupae are aquatic. The name of the 

 order signifies "hairy winged"; the hair is, however, often 

 difficult to see without a lens and sometimes it is almost as 

 scale-like as in some Lepidoptera. The adults are fre- 

 quently attracted to our porch lights, with many people 

 passing for moths that hold their wings trimly against the 

 sides of their bodies and have very long antennas. The 

 larvae are popularly called Caddice- or Caddis-worms 

 the term coming from a German word for "bait" because 

 they were used for that purpose. In these days of dry 

 flies the adults serve as models for such favorites as the 

 Duns. Most of the larvae make portable houses for 

 themselves (see Plate XV). Phryganea interrupta and 

 Platycentropus maculipennis, both living in still water, use 

 light material, the former clipping pieces of leaves and 

 neatly fastening the edges together, the latter cutting 

 small sticks in short lengths and arranging them crossways 

 of its body. Molanna cinerea, Notidobia americana (case, 

 a narrow cone), Psilotreta frontalis (a similar case but 

 blunter, nearly cylindrical), and Helicopsyche annulicornis 

 all live in running water and build of sand. Halesus argus 

 also lives in running water but weights the case of sticks 

 with stones and shells, not always being careful to select 

 unoccupied shells either. In these and many other such 

 instances, the larvae go about with only their heads and 

 legs sticking out of their homes and are ever ready to 

 withdraw even those on approach of danger. The 

 materials used in constructing the cases are fastened 

 together with silk; when time for pupation comes, the 

 whole case is anchored with silken cords to some under- 



57 



