Found this version on Kieron Jenkins blog http://ronsfishing.com/2013/05/24/its-mayfly-time/ Tied here as a March Brown; change colors to suit your needs

hook - Tiemco 300 #10
thread - Danville 6/0 brown
tail - pheasant tail
abdomen - dubbing tan
rib - pheasant tail (twisted it with tying thread for re-enforcement; wire rib could be used, as well)
wing - CDC brown dun
thorax - Haretron dark
hackle - barred rusty dun


Regards,
Scott