Since a few tan caddisflies were fluttering about, I gave Robin a size 16 Elk Hair Caddis. We got into position, and I coached her as she cast to the fish. She was doing everything right. Time and again, her cast unfurled perfectly above the water, and her fly landed softly on the surface, where it drifted drag-free over the trout's nose. But the trout wouldn't take. She tried twitching the caddis and did so almost expertly, but to no avail.