THE NET-MAKING CADDIS WORM 



have become the tubular pupal case of a net-making 

 caddis fly. Later in the season the mode of building 

 here described was confirmed by observations fortunately 

 made upon a half-grown larva working in natural site 

 within the run itself. 



Curiosity having been satisfied, the ingenious builder 

 was replaced in favorable conditions, and left to restore 

 its fallen house or erect a new one. The pan was cov- 

 ered with netting in the hope that the larva would 

 pupate, and by-and-by emerge as an imago or perfect 

 hydropsychid fly, and thus be captured and identified. 

 This hope was disappointed; but within the pan was 

 found, beneath a small cairn, a tough, silken, tubular 

 case which held the dead body of a pupa. This marked 

 the failure of some larva to attain its perfect life. It 

 was the remains of our little builder, or mayhap of one 

 of its fellows. 



Another characteristic of hydropsychid cairns, and 

 the most striking of all, is now to be told: they are 

 fishing - lodges ! This cairn -making caddis is a fisher 

 worm, and earns its title of "net-making" or "net- 

 building" by taking its prey in a woven net which is 

 spread against some part of its cairn, or annex thereto, 

 usually near the circular door of the tube. As the 

 cairns are placed on the edge or facing the course of 

 the current, such small-fry larvae as it feeds upon drift 

 into and are stopped by or entangled within the net, 

 and thus are captured. 



While noting the structure and arrangement of sev- 

 eral of these nets grouped upon a plate, my thoughts, 

 by that strange power of association which puzzles 

 philosophers, were carried back through half a century, 

 to boyhood fishing-days in eastern Ohio. I seemed to 



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