Pale and Dark Grannom caddis larva/pupae (one pattern does both). This insect can be found in nearly all riffles and moving water with rock and cobble bottoms. Their cases are distinctive with many layers of finely shaped fibers glued together in the shape of a skinny pyramid with the top cut off. Grannom activity continues all year long subsurface, but is lowest in the winter. Pale is best March - July, and Dark from July - Nov, but I've caught fish on both March- Nov. Fish this fly dead drift and as near to the stream bottom as you can get. Allow the fly to swing out/drag at the end of the drift.
Size 12-16 Scud Hook. Add a bead (gold seems to work best for the pale grannom) and weight with lead wire as desired. Mix 50/50 Yellow and Natural Hare's Ear dubbing. 6/0 Uni dark brown (the thread color if VERY important). Dub three fourths of the available shank with the dubbing mix. Dub loosely. Dub a dark brown thorax, whip finish. Use a dubbing brush to loosen the body and thorax fur slightly. When this fly is wet the abdomen portion will become translucent and the darker thread will show through. If you've achieved this in your tie, you've done it right.
The body on the Dark Grannom is Olive/Brown or dark olive, and the thorax is black or dark brown. Use a black tungsten bead. The body of this fly is not translucent when wet but do brush out fibers on the abdomen and thorax.