AQUATIC INSECTS 



Caddis flies — Trichoptera 



Adult caddis flies look like moths but their bodies are more 

 slender and they are more delicately built. They are soft 

 brown, or gray, sometimes black, very rarely bright colored. 

 Their four wings are folded like a tent over their backs, and 

 their thread-like antennae, often longer than their bodies, are 

 extended far out in front of them. As in the butterflies and 

 moths their color lies mainly in the long, silky hairs and scales 

 which cover their wings and soft bodies. Caddis flies do not 

 go far from the watersides and they are seldom seen in the 

 daytime. Some swarm at dusk over water and under trees 

 but at night they gather around electric lights which are 

 near streams or on lake shores, and they may then be seen by 

 hundreds, creeping up on the lamp posts or fallen upon the 

 ground below them. 



Fig. 1 88. — Caddis fly life-history: i, larva; 2, pupa; 

 3, adult; 4, leaf-case. 



Caddis flies are mostly known by their larvce, the familiar 

 caddis worms or stick- worms which live in ever}^ brook (PI. I), 

 often creeping over the bottom where they can be clearly 

 seen from the banks. The best known are those which live 

 in cases made of little pebbles, or sticks or leaves which they 



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