Midge / EmergersGrannom Pupa and Ovi-Grannom
Hans Weilenmann built this as a pair: a weighted pupa with a rabbit-and-hare body, peacock herl head, and ringneck pheasant hackle to fish the ascent, and an Ovi-Grannom dressed with a brown goose-biot abdomen, hare's-ear thorax, and CDC wing for egg-laying females on top. Fishing them together covers a grannom hatch from below the surface to on it. The pupa works a dead drift or gentle swing while the CDC pattern rides in the film.
Spring, Summer, Fall
Intermediate
Trout
Feb 2026
Overview
The pupa carries a cream rabbit and dyed-olive Argentinean hare body in a 3:1 blend, ribbed with black nylon rodwinding thread and finished with a peacock herl head and a ringneck pheasant neck hackle for legs. The companion Ovi-Grannom adds an olive hare egg sack behind a dyed-brown goose-biot abdomen, a natural CDC wing, and a dark-olive hare's-ear thorax spun in split thread for legs. Hans Weilenmann dressed both to match the ascending pupal stage and the returning, egg-laying adult of the same hatch. Fished as a pair on moving water, the weighted pupa searches the water column while the CDC-winged adult covers risers once egg-laying females return to the surface.
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Materials
- Grannom Pupa — Hook:
- Grip 14723BL #14
- Grannom Pupa — Thread:
- Benecchi 12/0, dark brown
- Grannom Pupa — Head:
- Peacock herl
- Grannom Pupa — Hackle:
- Ringneck pheasant neck "ring" feather
- Grannom Pupa — Rib:
- Nylon rodwinding thread, black
- Grannom Pupa — Body:
- Rabbit, cream; Argentinean hare, dyed olive - 3:1
- Ovi-Grannom — Hook:
- Tiemco 102Y #15
- Ovi-Grannom — Thread:
- Benecchi 12/0, dark brown
- Ovi-Grannom — Egg sack:
- Argentinean hare, dyed olive
- Ovi-Grannom — Abdomen:
- Goose biot, dyed brown
- Ovi-Grannom — Wing:
- CDC, natural
- Ovi-Grannom — Thorax/Legs:
- Hare's ear, dyed dark olive - in split thread
Behavior & Presentation
Natural Behavior: Grannom caddis pupae ascend through the water column during spring emergence windows, rising from riffle substrate toward the surface with gas bubbles trapped under their wing cases. These pupae exhibit jerky swimming motions during ascent, pausing mid-column before continuing upward through the film where they transform into adults.
Where Trout Eat It: Trout feed almost exclusively on grannom pupae during spring emergence windows when pupae rise toward surface mid-morning through noon.
How to Fish It: Swing weighted pupa with 3-inch pulls or dead drift under indicator allowing fly to lift at drift's end.
Best Water: Target riffle edges and current seams where ascending grannom pupae concentrate during synchronized emergences.
Strike Type: During the weighted swing with 3-inch pulls or dead drift under indicator, watch for subtle indicator hesitations or quiet sips as pupae rise. Gentle hook sets are essential when the indicator dips or the drift line tightens at drift's end.
Fishing Strategy
Rigging Suggestions: Use a 12-15 foot leader with 6X-7X tippet. Fish alone or as a dropper beneath a small dry fly.
Seasonal Timing: Most effective during peak feeding periods at dawn and dusk. Water temperatures between 45-65°F typically produce best results.
Pro Tips: Sinks at a moderate rate depending on hook weight. The natural materials blend well with the aquatic environment.
Entomology
Midge pupae ascend slowly through the water column in jerky, undulating motions before hanging helplessly in the surface film while their adult forms emerge from pupal shucks. Fish station themselves at specific depths to intercept these ascending pupae because the insects are completely vulnerable during transformation and cannot evade predators effectively.
- Order
- Diptera
- Family
- Chironomidae
- Common Name
- Midge
- Organism Type
- insect
- Life Stage
- general
