THE NET-MAKING CADDIS WORM 



about on the bottom of running brooks and creeks, 

 until ready to pass from the larval stage. Then it 

 fixes its case to a convenient rock or pebble and shuts 

 itself in to pupate. A score or more of such cases may 

 be found upon a stone as big as one's fist. To the 

 oddity of its appearance is due its wide popularity; and 

 certainly it is a curious object as it slowly plods along 

 beneath its mosaic-work armor of tiny stones, ever and 

 anon thrusting its head and the upper part of its body 

 out of its artificial shell. 



But one rarely hears of the net-weaving caddis. The 

 author confesses that until recently he knew it only 

 from the books. While collecting a few specimens of 

 the familiar armor-plated species from Brookcamp Run, 

 a stream that passes through an open wood on his 

 country-place, he drew from the water many of the 

 peculiar domiciles of a net-making species, probably 

 Macronema rebratum Hagen. His interest in them grew, 

 and led to prolonged studies, some of which he hopes the 

 reader will be glad to share with him. 



Let us remove from this short stretch of riffle some 

 of the stones that line the bottom. Our tray contains 

 specimens on the edges and under-sides of which are 

 fastened not only the compact, pellet-covered, tubular 

 cases of the familiar caddis fly just mentioned, but many 

 others of a quite different structure. They are little 

 piles of pebbles held loosely together by silken threads; 

 yet they adhere to one another and to their stone 

 "host" firmly enough to resist the action of the current 

 and the strain of removal. A number of specimens 

 gathered three months ago show the little cairns un- 

 broken. 



They are made up of pebbles from the bigness of a 



273 



