The forgotten underwing in the X2 Caddis

[Byron haugh]

I found it quite interesting that the X2 Caddis tied by Bucky McCormick of Blue Ribbon Flies in a video on their site leaves out the underwing....
Anyone else notice this?
I find it odd as BRF invented the original X a Caddis and popularized the "Improved X Caddis" which was later dubbed the X2 Caddis. BRF credits other tiers for the "improved" version.

If you look are Arrick's video, you will see it tied with the underwing, while the video by Blue a Ribbon leaves it out ????