The Sparkle Dun is the go-to imitation for mayflies hatching in slow water — flat pools, spring creeks, tailwaters. Unlike a high-floating Parachute Adams, the Sparkle Dun rides flush in the film with a Z-Lon "shuck" trailing behind, suggesting a half-emerged dun struggling out of its nymph case.
Sizes 14–22 cover most mayfly hatches. Tie one in olive for BWO and PMD; gray for Hendricksons; cream for Sulphurs. When trout refuse a high-floating dry, this is often what they want.