First saw parasols in Schollmeyer and Leeson's Tying Emergers. Kelly Glissmeyer put together a nice Fly-of-the-Week here a while back; used his method (as well as the chartreuse wire rib he's fond of) and added a bit of contrast to improve visibility for me. Tied here as a PMD; change color/size to suit your needs.
hook ? Dai Riki 125 #16
thread - Danville 6/0 pale yellow
shuck/wingcase ? Congo Hair brown
rib - small wire chartreuse
abdomen ? pheasant tail
thorax - Superfine dubbing PMD
indicator - Congo Hair baitfish tan/McFlyfoam hot pink
Part 1
tie an improved clinch knot in a loop of 3x mono (apologies for the dirty fingernails; yardwork comes first)
insert a hank of CH/McFlyfoam; pull tight/trim
mash barb, start thread at point above point; tie in CH (let tag end extend over hook eye), rib, wrap to bend
tie in pt; wrap to point above point