94 



ELEMENTARY ENTOMOLOGY 



to both the neuropterous insects and the Lepidoptera. The mouth- 

 parts of the adults are quite rudimentary. The hind-wings are often 



somewhat larger than the 

 fore-wings and are then 

 folded under them in repose, 

 the fore-wings being held 

 like a roof over the back. 

 The antennae are usually very 

 long and slender. The lar- 

 vae are aquatic and form an 

 important item of fish food. 

 Some of them build most 

 interesting little cases from 

 grains of gravel, small shells, 

 bits of twigs, pine needles, 

 or whatever rubbish may be 

 at hand, lined within with 

 silk, which they carry around 

 with them, the head and 

 thorax projecting out as they 



move or feed. Every small pool or brook harbors some of these 

 interesting case bearers, which will hardly be distinguished except by 

 closely watching the bottom until they are seen in motion. Most of 

 these larvae are herbivorous, feeding on whatever vegetable matter 

 is available, and look like small 

 caterpillars. The caddis-worms of 

 one group construct silken nets 

 across small rapids, between stones, 

 or upon the brink of little water- 

 falls, which are doubtless of serv- 

 ice in catching the tiny insects 

 which float downstream, as the lar- 

 vae which make them are known 

 to be carnivorous. When ready to change to a pupa, the caddis- 

 worm closes up the entrance to its case, but leaves an opening for 

 the water to flow through so that the pupa can breathe, sometimes 

 making a simple grating of silk over the entrance. Upon trans- 

 forming to the adult the caddis-fly secures almost immediate use 



FIG. 120. Caddis-fly larval cases. (Enlarged) 

 (After Furneaux) 



FIG. 121. Adult caddis-fly (Goniotau- 

 lius dispectus Walk). (Enlarged) 



(After Needham) 



