I know that "Czech Nymphing" is a technique or style of nymphing, but whenever I see a fly called a "Czech Nymph" it is always the same type of fly - grub-style and heavily weighted. Are all "Czech Nymphs" imitating a caddis larva, mostly with a hot spot? I never see a heavily weighted mayfly-looking nymph with a hot spot called a "Czech Nymph". I realize you can use any type of heavier weighted fly in a Czech Nymphing rig, but is that just the type of fly that was originally used in that set-up and is now called a Czech Nymph?
I'm leaving in a week and a half for my annual trip to northern New Mexico and a couple of streams - the Costilla, Comanche, and the Culebra in southern Colorado to name a few - have a lot of deep undercut banks that the "Czech Nymphing" technique could be productive in and I just got curious about the origin of the name of that style of fly.

Joe