This fly is an old Welch pattern imitating an aquatic beetle.
The attached illustration is by Charles Orvis in Favorite Flies and Their Histories (1892) by Mary Orvis Marbury.
Lay down a base of red thread
Tie in length of black silk thread at the hook bend; wrap a tag with the black thread; tie off and clip extra
Tie in the gold wire to use as a rib
Tie in three or four strands of Peacock herl to the tag; touching wrap to an eye length behind eye (leave room for a front hackle); tie off; clip extra
Spiral wrap the wire around the herl body; tie off; helicopter off (or clip) extra
Tie in a soft front hackle (traditionally used coch-y-bonddu feather that had black rim and center with red between the black); wrap to end of feather; catch in; pull back on hackle fibers and wrap back over feather end to make the head; clip or snap off extra hackle
Finish head; whip finish; head cement.
