"But when I do.........I prefer a green butt version.........
This pattern proves a couple of things:
1. I could never be a barber
2. I don't tie the Goddard Caddis very well.
Having said that, if tying an adult caddis I believe it should have either a trailing shuck or a green butt to imitate the egg laden female returning to the water.
The original G&H Sedge had a green underbody pulled up and tied off, but it was not just at the butt..........was not done to imitate an egg sack.