Jay Fullum, Fishy’s Flies, Mechanicsburg (PA), Stackpole Books, 2002, p. 34.
The stomach was full, so the fish had been feeding on something. I opened it with my kniffe and to my surprise, it was full of small pebbles. I carefully picked through the contents, searching for some clue as to why this trout had been feeding on rocks. Finally I found an intact clump and discovered that the trout had been feeding on caddis larvae, eating them along with the cases the insects had built using small pebbles from the bottom of the stream.
This triggered an idea. before leaving the water that morning, I collected some of the fine sand and pebbles from the bottom of the stream, filling a container I normally use when collecting insect samples. Later that week, I rinsed the material to remove any debris and spread it out in a shallow container to dry. After the sand and pebble mixture was dry, I sifted it using several different wire sieves to produce a small quantity of fine, medium, and coarse material.
Making up a supply of the Stone Caddis was easy. I simply prewrapped a few hooks with thread, applied a little five-minute epoxy to the rear portion of the hook shank, and set the hook into a small pile of the material. As the epoxy began to Harden, I removed the hook and kneaded the material into the shape of the caddis cases I’d seen clinging to the larger rocks on the bottom of the stream.