Wire March Brown (Semperfli 0.2mm) (1 strand (rib))
Mirage opal tinsel Opal, large (1 strand (wing case))
UV nymph dubbing Tan UV nymph dubbing (Dubbing loop (body))
How to tie it
Slide the bead to the eye with the countersunk (ceramic) side forward and start the thread; build a small thread dam behind the bead to push the mass up and forward so the fly rides inverted.
Wrap the thread back to the bend and tie in 8-10 Partridge fibers for the tail, a little shorter than the shank, imitating the long tails of the swimming Callibaetis.
Tie in the wire rib along the far side and bind it down the full body length up to the bead.
Flip the fly (balanced style) and tie in a length of large Mirage opal tinsel at the front for the shell-back/wing case.
Form a short dubbing loop (about two shank lengths), load it with tan UV dubbing, spin it tight and wrap a slim body forward to the thorax, then brush it out buggy.
Counter-wrap the wire rib forward in evenly spaced turns to segment and reinforce the body, then helicopter off the excess.
Pull the Mirage tinsel forward over the top as a wing case and secure it behind the bead.
Tie in the Partridge feather and take one or two turns for legs, sweeping the fibers back, then secure.
Build a neat thread collar behind the bead, whip finish and add a drop of cement.