Dry FliesED (Ephemera Danica)
Hans Weilenmann built the ED to match Ephemera danica, tying a tan Argentinean hare abdomen ribbed in doubled brown Uni-thread and a dark olive Argentinean hare thorax under a natural deer hair wing and head. A sparse muskrat guard hair tail and the substantial deer hair collar give it the bulk needed for one of Europe's largest mayflies.
Spring, Summer, Fall
Intermediate
Trout
Feb 2026
Overview
Tan Benecchi thread underlies a tan Argentinean hare abdomen segmented by a doubled and twisted brown Uni-thread rib, a sparse muskrat guard hair tail, and a dark olive Argentinean hare thorax, with natural deer hair forming both the wing and the head. The deer hair provides the flotation needed to support a fly sized for Ephemera danica, a mayfly considerably larger than typical stream naturals. That size and buoyancy matter because these duns ride the surface for extended distances while their wings harden before their first flight. It's built for the brief but intense danica emergence on moving water and stillwater across spring through fall, when large trout target the sheer bulk of the naturals.
Where to Buy This Fly
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Materials
- Hook:
- Grip 14723BL #12
- Thread:
- Benecchi 12/0, tan
- Rib:
- Uni-thread 6/0, brown - doubled and twisted
- Abdomen:
- Argentinean hare, tan
- Tail:
- Muskrat, guardhair - sparse
- Thorax:
- Argentinean hair, dark olive
- Wing/Head:
- Deer hair, natural
Behavior & Presentation
Natural Behavior: Large Ephemera danica mayflies drift with wings held vertically upright after emergence, their substantial cream-colored bodies and long tails creating an unmistakable profile on European chalk streams. The extended body construction and oversized deer hair wings replicate the impressive size and sail-like drift of these premium mayflies.
Where Trout Eat It: Trout rise confidently to large mayfly duns floating in chalk stream glides and smooth pool surfaces, focusing on slow-drifting sections where danicas accumulate.
How to Fish It: Cast well upstream of rising fish to allow fly to settle naturally into feeding lane, using long delicate casts with abundant slack.
Best Water: Chalk stream glides with smooth current and meadow stream pool flats. Target back eddies near weed beds where large duns collect.
Strike Type: Big trout rise confidently to large mayflies with head-and-tail porpoising rises or aggressive surface boils; wait to see the fly disappear before setting.
Fishing Strategy
Rigging Suggestions: Use a 9-12 foot leader tapering to 5X tippet for delicate presentations. Apply floatant to the body and hackle.
Seasonal Timing: Most effective during peak feeding periods at dawn and dusk. Water temperatures between 45-65°F typically produce best results.
Pro Tips: Time fishing to coincide with peak emergence periods. The pattern's large profile and high visibility make it an attractor even outside specific hatches.
Entomology
Large mayflies ride the surface with wings upright after emergence, drifting considerable distances while their exoskeletons harden and wings fully expand before attempting first flight. Trout recognize these substantial insects as high-value meals, rising confidently to large adults that sail predictably in slower current lanes.
- Order
- Trichoptera
- Common Name
- Caddisfly
- Organism Type
- insect
- Life Stage
- adult
