White Miller (Nectopsyche spp.)

Caddis, hatching July–September, active in water between 60 and 74°F, and imitated at #14–18. Recorded from the Wisconsin driftless and northern Wisconsin, where 1611 Wisconsin rivers on this site carry a page.

#14–18Hook size
60–74°FWater, active
Jul–SepPeak months
3Life stages fished

Subbasins with trout water where it is on record: 37 of Wisconsin's 43.

See Wisconsin's trout water on the live map → Every reach coloured by water temperature — the water these hatches come off.

What it is

Caddis · Nectopsyche spp. · larva → pupa → adult

A cream-to-white caddis with pale wings folded in a tent over the body, and long pale antennae. In the evening light a swarm of them over the water is unmistakable.

A pale cream caddis that comes off in clouds on midsummer evenings and is a Wisconsin classic. It swarms over the water at last light long after the fish have stopped rising to it, so the fishable window is earlier than the spectacle suggests.

When it hatches

Peak is July–September. 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.

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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.

60°F 74°F

Active from 60°F to 74°F. On this map that is cold-transitional, cool, warm water — the band crosses 2 of the three breaks 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
larva	A case-builder in slower sandy and silty water, using sand grains and plant fragment. Rarely fished directly.
pupa	Rises to the surface at dusk to emerge. This is the productive stage and the one the fish are usually on before the visible swarm starts.
adult	Swarms in clouds at last light and after. Egg-laying females come back to the water, but much of the visible flight is above it, which is why the fishing often ends before the spectacle does.

Matching flies

4 patterns in this book imitate the White Miller, 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.

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.

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 Upper Peninsula MI
the Wisconsin driftless WI
northern Wisconsin WI
southeast Minnesota MN

Rivers in these regions with a page here

Related hatches

Same family, or overlapping this one's calendar on the same water.

Open the trout map →Every trout stream near you, coloured by today's water temperature.