The caddis flies which should possess the greatest interest 

 for us, because it is a personal interest, belong to this group. Their 

 larvae are the only caddis 

 worms which are carnivo- 

 rous. They are found both 

 in streams and in ponds, 

 but more commonly in 

 streams. They are elong- 

 ate and slender, with short 

 legs, and with anal pro- 

 jections Which bear Strong *> "5- Trap and larval case of 



Hydiopsyche. (Author s illustration.) 



curved claws with which 



they hold to the surface of rocks or to their cases. Their cases 

 are fixed and are generally composed of bits of stone fastened to 

 large stones or rocks at the bottom of the 

 water. Sometimes several larvae appear to 

 live in company in a common case, being 

 covered by a sheet of silk, to which minute 

 fragments of leaves and sticks are fastened. 

 There is usually more silk in the con- 

 struction of the cases of these insects than 

 with the caddis worms of the other families 

 which have stony cases, and although the 

 stones attached to it may be few in number, 

 there is apt to be a pretty dense, silken tube. 

 Sometimes this tube is simply covered with 

 slimy mud and has no other foreign objects 

 attached to it. Some of these larvae prey 

 upon other aquatic insects and it is prob- 

 able that this is a general habit of the group. 

 An interesting form which I have 

 watched in Rock Creek, near Washington, inhabits a case shaped 

 like a funnel, the tube of the funnel bent nearly at right angles 



204 



Fig. 1 1 6. Larva of 

 Hydropsyche, the 

 maker of the trap, 

 figure 1 1 5. 

 (Author's illustration.) 



