Yellow Belly Olive Mayfly Dun

by @dekasso

Dry fly

Olive and gold drifting through lavender dusk

A slim two-tone mayfly dun in olive and yellow, size 14, for trout rising to duns on rivers.

A slim mayfly dun with an olive back over a bright yellow belly, crowned by tall grey wings. Fine silver wire segments the two-tone body, and long brown fibers form the splayed tail and sparse hackle.

Imitates
Olive and yellow mayfly duns, typically late spring and early summer afternoons
Hook
size 14
Tippet
5Xrule of three
  • Olive back over a yellow underbody
  • Silver wire rib segments the body
  • Grey mallard quill wings stand upright
  • Long splayed brown hackle-fiber tail
  • Size 14 dry-fly hook

On the water

A dry fly riding the surface of a trout river

Olive on top, yellow underneath, and a thin silver rib stitching the two together. Grey quill wings stand tall and lean back. A long brown tail fans out behind like whiskers.

Fish it on the surface when duns are riding the current and trout are sipping. Cast above the rise, mend once, and let it float drag-free through the seam. The yellow belly is the side the fish sees.

Olive Antron yarn makes the back. Pull it tight and centered over the dubbed body before the wire goes on, so each wrap of silver pinches the olive down into clean segments.

A coiled leader, tippet spools and an open fly box on slate

Rigging

Tippet
5Xhook size divided by three
Leader
Nine feet, tapered — longer and finer in flat water
  • Rig on 5X or 6X tippet with a long leader for flat, clear water.
  • Dress the hackle and wing with floatant so it rides high through the drift.
  • Cast a few feet above the rise and mend to keep the drift free of drag.

Where and when

Hatch
Olive and yellow mayfly duns, typically late spring and early summer afternoons
Target
Trout
Water type
Riffles, smooth glides and slow pools on rivers
Also fishes
Also fishes well on slow flats and stillwater margins in calm evening light when single duns drift and trout cruise.

Make it yourself

Intermediate7 materials · 10 steps

Style
Dry fly
Hook
Standard dry-fly hooksize 14
Thread
Brown 8/0
Fly-tying materials laid out on a dark bench

Materials in the order they go on the hook

  1. TailBrown hackle fibers
  2. RibSilver wire
  3. BackOlive Antron yarn
  4. BodyYellow dubbing
  5. WingGrey mallard quill slips
  6. HackleBrown rooster hackle
  7. HeadBrown thread

Details

Imitates
Mayfly
Colors
Olive, Yellow, Silver, Brown, Grey
A fly-tying vise holding a bare hook on a wooden bench

How to tie it

The steps, from first wrap to whip finish (10)
  1. Mount the hook in the vise and start the brown thread behind the eye, then wrap a smooth base to the bend.
  2. Tie in a bunch of brown hackle fibers for the tail, about one shank long, and let them splay slightly.
  3. Tie in the silver wire at the bend, leaving it trailing to the rear.
  4. Tie in a strand of olive Antron yarn on top of the shank at the bend, pointing rearward.
  5. Dub a thin, gently tapered yellow body forward to about three quarters of the shank.
  6. Pull the olive yarn tight over the top of the body and tie it off in front of the dubbing, then trim.
  7. Wrap the silver wire forward in five or six evenly spaced turns, tie it off and trim the tag.
  8. Match two grey mallard quill slips, tie them on top as an upright wing angled back, roughly one shank long.
  9. Tie in the brown rooster hackle and wrap two or three turns, letting the long fibers sweep down and back.
  10. Build a small, neat tapered head with the thread and whip finish.
Proportions (4)
  • Tail: about one hook shank long, fibers slightly splayed.
  • Body: slim, ending three quarters up the shank to leave room for wing and hackle.
  • Wing: roughly one shank long, upright and swept slightly back.
  • Hackle fibers: about one and a half times the hook gap, kept sparse.
Tips (4)
  • Use very little yellow dubbing; a thin body shows the olive and yellow split far better.
  • Keep the olive yarn centered on top so the yellow shows evenly along both sides.
  • Pair the quill slips from matching left and right feathers so the wing sits straight.
  • Space the silver wire turns evenly to make crisp, regular segments.
Common mistakes (4)
  • Overdubbing the body hides the split colours; twist on less dubbing than feels right.
  • Loose olive yarn rolls to one side; hold it firmly on top while tying off.
  • Crowding the eye leaves no room for the head; stop the body at three quarters of the shank.
  • Too many hackle turns make it bushy; two or three wraps are enough.
A dozen-fly materials kit laid out on slate with its recipe card.
The kit

Every kit size

Materials only

Size 14 · Materials only · 12 flies

$55.05

$4.59 a fly

Includes Standard dry-fly hook · and 9 more

Every item in this kit · 10 items

Hooks & beads

  • Standard dry-fly hook$6.501 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$2.951 spool
  • Silver wire$3.251 spool

Materials

  • Brown hackle fibers$11.951 saddle pack
  • Olive Antron yarn$3.501 pack
  • Yellow dubbing$4.501 dispenser
  • Other material: Grey mallard quill slips$4.501 pack · From the recipe row "Wing"
  • Brown rooster hackle$11.951 saddle pack

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

Size 14 · Materials only · 48 flies

$92.53

$1.93 a fly

Bought separately $97.40 · you save $4.87

Includes Standard dry-fly hook · and 9 more

Every item in this kit · 10 items

Hooks & beads

  • Standard dry-fly hook$132 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$5.902 spools
  • Silver wire$3.251 spool

Materials

  • Brown hackle fibers$23.902 saddle packs
  • Olive Antron yarn$3.501 pack
  • Yellow dubbing$92 dispensers
  • Other material: Grey mallard quill slips$92 packs · From the recipe row "Wing"
  • Brown rooster hackle$23.902 saddle packs

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

Size 14 · Materials only · 144 flies

$231.26

$1.61 a fly

Bought separately $262.80 · you save $31.54

Includes Standard dry-fly hook · and 9 more

Every item in this kit · 10 items

Hooks & beads

  • Standard dry-fly hook$351 × 100 + 2 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$17.706 spools
  • Silver wire$9.753 spools

Materials

  • Brown hackle fibers$71.706 saddle packs
  • Olive Antron yarn$10.503 packs
  • Yellow dubbing$184 dispensers
  • Other material: Grey mallard quill slips$22.505 packs · From the recipe row "Wing"
  • Brown rooster hackle$71.706 saddle packs

Finishing

  • Head cement$5.951 bottle

Guide

  • Printed recipe and tying stepsIncluded1

With vise & tools

Size 14 · With vise & tools · 12 flies

$205.05

$17.09 a fly

Includes Standard dry-fly hook · and 18 more

Every item in this kit · 19 items

Hooks & beads

  • Standard dry-fly hook$6.501 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$2.951 spool
  • Silver wire$3.251 spool

Materials

  • Brown hackle fibers$11.951 saddle pack
  • Olive Antron yarn$3.501 pack
  • Yellow dubbing$4.501 dispenser
  • Other material: Grey mallard quill slips$4.501 pack · From the recipe row "Wing"
  • Brown rooster hackle$11.951 saddle pack

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

Size 14 · With vise & tools · 48 flies

$235.03

$4.90 a fly

Bought separately $247.40 · you save $12.37

Includes Standard dry-fly hook · and 18 more

Every item in this kit · 19 items

Hooks & beads

  • Standard dry-fly hook$132 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$5.902 spools
  • Silver wire$3.251 spool

Materials

  • Brown hackle fibers$23.902 saddle packs
  • Olive Antron yarn$3.501 pack
  • Yellow dubbing$92 dispensers
  • Other material: Grey mallard quill slips$92 packs · From the recipe row "Wing"
  • Brown rooster hackle$23.902 saddle packs

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

Size 14 · With vise & tools · 144 flies

$363.26

$2.52 a fly

Bought separately $412.80 · you save $49.54

Includes Standard dry-fly hook · and 18 more

Every item in this kit · 19 items

Hooks & beads

  • Standard dry-fly hook$351 × 100 + 2 × 25 · size 14

Thread & wire

  • Brown 8/0 thread$17.706 spools
  • Silver wire$9.753 spools

Materials

  • Brown hackle fibers$71.706 saddle packs
  • Olive Antron yarn$10.503 packs
  • Yellow dubbing$184 dispensers
  • Other material: Grey mallard quill slips$22.505 packs · From the recipe row "Wing"
  • Brown rooster hackle$71.706 saddle packs

Finishing

  • Head cement$5.951 bottle

Tools

  • Rotary pedestal vise$791
  • Ceramic bobbin$141
  • Fine-point scissors$161
  • Whip finisher$91
  • Hackle pliers$71
  • Bodkin$51
  • Bobbin threader$41
  • Dubbing wax$41
  • Canvas tool roll$121

Guide

  • Printed recipe and tying stepsIncluded1

The creator

An illustrated portrait for Dekasso (an illustration, not a photograph)

Dekasso

@dekasso

Wherever the truck rolls to a stop.

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See everything by @dekasso