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Light Cahill
A dry fly, tied #12–16, a summer pattern. It is tied against 2 named insects in this book — May–August.
- #12–16Hook size
- dry flyType
- SummerSeason
- 2Hatches matched
What it looks like
A drawing, not a photograph, and not traced from one. Its proportions were read off 5 independent reference photographs of the pattern and written down as 5 measured characteristics — wing angle, tail length against the shank, how far a hackle fibre reaches — every one of which had to hold across more than one of them before it could be drawn. What survives across many photographs of a fly is the fly.
What it imitates
Each of these is the same hatch record the app's own panel reads, so a pattern recommended on a river card in the app is recommended for one of the insects below.
- Cream Cahill Maccaffertium modestum · July–August · 62–74°F · #14–16
- Light Cahill Maccaffertium ithaca · May–July · 55–68°F · #12–16
Tying recipe
In tying order. This dressing is the standard one — these patterns have been in the publicrecord for decades — and materials substitute freely: the proportions and the silhouette are the pattern, not the brand of dubbing.
| Hook | Standard dry-fly hook, sizes 12–16 |
|---|---|
| Thread | Cream 8/0 |
| Tail | Cream hackle fibres |
| Body | Cream fox or synthetic dubbing |
| Wings | Wood-duck flank, upright and divided |
| Hackle | Light ginger |
When to fish it
The last hour of light from late May through midsummer on freestone water. Fish it tight to rock-lined banks, where the clinger nymphs live.
A summer pattern. The insects it matches are active may–august, in water from 55°F to 74°F.
Target species
- Trout
Rivers it fishes well
Rivers with a page here that sit in the regions where the insects this pattern imitates are recorded. It is a claim about coverage, not a report of a fish caught.
- Au Sable River northern lower Michigan · July mean 72.1°F
- Catawba River the North Carolina mountains · July mean 76.7°F
- Jackson River the Virginia mountains · July mean 66.3°F
- Muskegon River northern lower Michigan · July mean 71.0°F
- Escanaba River the Upper Peninsula · July mean 68.3°F
- Saint Croix River northern Wisconsin · July mean 77.2°F
- Smith River the Virginia mountains · July mean 51.9°F
- Tygart Valley River the Virginia mountains · July mean 74.6°F
- Kalamazoo River southern lower Michigan · July mean 71.3°F
- Aaron Creek the North Carolina mountains · July mean 76.7°F
- Aaron Run the Virginia mountains · July mean 77.1°F
- Aarons Run the Virginia mountains · July mean 74.2°F
Related patterns
Same type of fly, or tied for the same insects.
- Rusty Spinner dry fly · #14–20 — Almost every mayfly spinner is rust-coloured. This covers the last hour of light.
- Adams (Catskill) dry fly · #12–20 — The original. Rides higher than the parachute in broken water.
- Adult Cranefly dry fly · #10–16 — Long trailing legs, sparse hackle, skittered rather than drifted. Autumn and spring evenings on the bank side.
- Adult Damsel dry fly · #10–14 — Blue or olive extended body on a foam post. For midsummer afternoons on slow weedy water.
- Blue Quill dry fly · #16–18 — Small dark mayfly dun. Spring Blue Quills and fall Mahoganies are the same fly.