What general style of pattern do you use for a mayfly dun hatch?

The abdomen is indeed a biot wrapped smooth. I really like the thin profile and the segmented body it gives the fly.

I wish I could tie these extended body parachutes - they have been very useful.
http://www.cabelas.com/dry-flies-parachute-extended-body-bwo-1.shtml

RE> “I wish I could tie these extended body parachutes - they have been very useful.
http://www.cabelas.com/dry-flies-par...dy-bwo-1.shtml

This method puts the parachute below the body (where the real bug’s legs are), rather than on top.

Put a #13 beading needle in the vise, horizontally. Tie a body with tails and wing on the needle.
Slide it off the needle. Tie a hackle feather on a scud hook. Mount the body, somewhat loosely.
Wind thread horizontally a few times, between body and hook.

Wind the hackle. Whip finish. Put a drop of CA glue at the fulcrum of the hackle finish off the fly.