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Little Sulphur (Ephemerella dorothea)
Mayfly, hatching May–July, active in water between 50 and 62°F, and imitated at #16–20. Recorded from the Virginia mountains, where 796 Virginia rivers on this site carry a page.
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- #16–20Hook size
- 50–62°FWater, active
- May–JulPeak months
- 4Life stages fished
What it is
Mayfly · Ephemerella dorothea · nymph → emerger → dun → spinner
A small pale mayfly, sulphur-yellow body washed with orange, pale dun wings and three tails. Distinctly smaller than the E. invaria sulphurs that precede it — a #18 where those are a #14.
The smaller, later half of what everyone calls 'the sulphur'. Where E. invaria comes off in the afternoon at a #14, dorothea comes off at dusk two or three sizes down, and a refusal in June is usually a size problem rather than a pattern one.
When it hatches
Peak is May–July. The pale months either side are the shoulder — the app widens a peak by one month in each direction and recommends the bug there, and no further: that widening is bounded so that a bug peaking in May is never offered in August.
peak shoulder not recommended
Water conditions
The band is a water temperature, not an air temperature, and it is the range in which this insect is worth fishing — for a mayfly that is the emergence window; for a scud or a midge it is simply the range trout will still eat one in.
Active from 50°F to 62°F. On this map that is cold, cold-transitional water — the band crosses 1 of the three break the river colours use. Breaks at 58, 64 and 70°F.
Stages
What the insect is doing, and what that means for what you tie on.
| Stage | What it is |
|---|---|
| nymph | A stout crawler in gravel and among weed, dark olive-brown. Available for months before the hatch and worth fishing as a dropper all spring. |
| emerger | Emergence is at dusk and in the film. The stuck-in-the-shuck stage is where most of the eating happens, and a low-riding comparadun is usually the difference between refusals and takes. |
| dun | Pale yellow, upright-winged, on the water in the last half-hour of light. It rides briefly in warm weather and much longer in cool. |
| spinner | Falls after dark, often over the same water an hour after the hatch. A rusty spinner fished blind into the sound of rises is the standard way to fish it. |
Matching flies
5 patterns in this book imitate the Little Sulphur, across its stages. Which one to tie on follows the stage the water temperature says it is in — the app makes that call on a live reading; this page lists the whole set.
- Pheasant Tail Nymph nymph · #12–22 — The mayfly nymph. Beadhead or not, size 16, and half the trout in the world have eaten one.
- RS2 emerger · #16–24 — The emerger that saves a hatch you cannot otherwise crack. Fish it in the film.
- Rusty Spinner dry fly · #14–20 — Almost every mayfly spinner is rust-coloured. This covers the last hour of light.
- Sulphur Comparadun emerger · #14–20 — No hackle, sits in the film. What to tie on when duns are drifting past untouched.
- Sulphur Dun dry fly · #14–18 — Pale yellow-orange. Evening hatch fly on nearly every eastern river.
Where to find it right now
The rivers with a page here that sit in this insect's regions, with a USGS gauge reporting water temperature. This list is re-ranked against the reading each gauge is sending now and today's date, so it is live — the fallback below it, if the readings do not arrive, is each river's measured July mean.
- Camp Branch the Virginia mountains · July mean 56.0°F
- Cascades Creek the Virginia mountains · July mean 59.2°F
- Left Prong Wilson Creek the Virginia mountains · July mean 59.2°F
- Lick Block Run the Virginia mountains · July mean 59.2°F
- Smith River the Virginia mountains · July mean 51.9°F
- Als Run the Virginia mountains
- Alum Creek the Virginia mountains
- Anderson Run the Virginia mountains
- Ararat River the Virginia mountains
- Auberry Creek the Virginia mountains
Regional presence
Regions, not collection records. This insect is recorded from the coarse regions below; nobody has surveyed which named river it has been caught on, and this page will not pretend otherwise.
- northern lower Michigan MI
- southern lower Michigan MI
- the Wisconsin driftless WI
- the Virginia mountains VA
- the North Carolina mountains NC
- southeast Minnesota MN
Rivers in these regions with a page here
- Jackson River
- Smith River
- Als Run
- Alum Creek
- Amos Branch
- Anderson Run
- Ararat River
- Auberry Creek
- Back Creek
- Back Creek
- Back Fork
- Back Run
- Baker Branch
- Baldwin Branch
- Baldwin Branch
- Barbours Creek
- Bark Camp Branch
- Bark Camp Branch
- Barkcamp Branch
- Barnard Creek
- Barney Run
- Barterbrook Branch
- Batie Creek
- Battery Creek
- and 772 more
Related hatches
Same family, or overlapping this one's calendar on the same water.
- Light Cahill Maccaffertium ithaca · Mayfly · May–July
- Sulphur Ephemerella invaria · Mayfly · May–July
- March Brown Maccaffertium vicarium · Mayfly · May–June
- Isonychia / Slate Drake Isonychia bicolor · Mayfly · June–September
- Yellow Drake Ephemera varia · Mayfly · June–August