Here's an underwater view of the pupal
shucks (Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult.) of several already-emerged
Brachycentrus numerosus caddisflies.
See many more fly fishing, trout stream, and stream insect pictures on the
Troutnut.com homepage and
discussion forum.