Look closely at these pictures of the case and you can see it's not solid wood pieces, but that some of the silk used to attach the wood is showing through in the cracks.
Pycnopsyche (Great Autumn Brown Sedges) Caddisfly Larva from Mystery Creek #62 in New York
Troutnut.com is a collection of pictures and information about fly fishing. Fly fishermen, fly tiers, and trout enthusiasts of all stripes can learn more about life beneath the surface of trout streams, as well as how to better imitate aquatic insects with artificial flies to catch trout. There are aquatic insect pictures, underwater pictures, landscape pictures, and a comprehensive reference to the common names of trout stream insects.