Mark Lord's take on the big mayfly. Original pattern called for poly yarn body; swapped that for foam to help keep all that iron on top, or at least flush in the film. Again, another one that, with a few mods in size and colors could be used for other plus-sized mayflies.
hook - TMC 5212 #6
thread/rib - UTC 140 hopper yellow
tail - stripped grizzly hackle stems
underbody - 1mm foam yellow
overbody - deer hair
wing - Congo Hair white
hackle - brown/grizzly mix
Part 1
mash barb, start thread at 70% mark; create a thread bump at point above barb
tie in 2 stripped hackle stems
taper the end of a strip of foam and tie in
wrap foam forward; tie off, trim and smooth with thread wraps
clean, stack, measure (extend gap width past shank) a clump of deer hair
tie in, keep the hair on top then continue wraps back towards the tail segmenting all the way, give a firm pull at the tail to flare the tips; return to the front with crossing wraps, trim butts