TRICHOPTERA 



77 



backs has been noted by everyone who 

 looks into a brook. 



The net-making caddisworms (Hydro- 

 psyche) live among the stems and stones in 

 the rapids of streams. Their young are larvae 

 and not nymphs. They differ most markedly 

 from the nymphs of the groups we have 

 been considering in being more wormlike in 

 form, in having a greater development of the 

 abdominal region of the body, less develop- 

 ment of the eyes, antennae, palpi and legs, 

 and no externally visible development of 

 wings at all. This last character at once dis- 

 tinguishes all true larvae of insects from 

 nymphs. 



Fig. 29. — The net-making caddis fly Hydropsyche. At the left below is a larva in its shelter, 

 its head behind its catching net. At the right is a pupa that has left its pupal chamber under the 

 barricade of stones below, and is swimming to the surface to transform. Above is the adult 

 caddisfly. The line at the right shows actual length. 



