Trying to understand more about cased caddis patterns.
My understanding is that a cased caddis pattern represents the larva stage of the caddis fly. The hackle is trimmed short giving it a spikey appearance, imitation the tiny prickly follicles it has (similar to a caterpillar).
If that it the case, then why do some larva patterns not have this spikey hackle? Like patterns that use green beads for example. And why are these patterns typically tied on an emerger hook, not a straight nymph hook like the cased caddis.
Also why is it called cased? Isn't a non-cased caddis called a pupa? Why not just call a cased caddis a caddis larva instead?