Mayfly, hatching June, active in water between 44 and 56°F, and imitated at #16–18. Recorded from southeast Minnesota, where 99 Minnesota rivers on this site carry a page.
Mayfly · Paraleptophlebia adoptiva · nymph → emerger → dun → spinner
A small, dark mayfly — slate-grey wings and a nearly black-brown body — coming off the same cold April water as the Hendrickson and often mistaken for a small one at a distance. Two tails, not three.
Runs with the Hendrickson and two sizes smaller. When fish refuse the bigger dun, this is usually why.
These are Minnesota's own dates, not this site's shared calendar. They are the Iron Blue Quill (Paraleptophlebia sp.) row of Hatch Chart for Southeast Minnesota Trout Streams, Minnesota Department of Natural Resources, Lanesboro Area Fisheries (Vaughn Snook, Assistant Fisheries Supervisor), as of 15 June 2016. The chart's calendar runs January to October and makes no claim about November or December. Its own footer says it is a general time frame, that some streams have only a few of these hatches, and that others may see hatches it does not list.
Peak is June. 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
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 44°F to 56°F. On this map that is cold water. Breaks at 58, 64 and 70°F.
What the insect is doing, and what that means for what you tie on.
| Stage | What it is |
|---|---|
| nymph | A slender, agile swimmer that lives in slower water and leaf packs rather than fast gravel. Small dark nymphs, size 16 to 18, are the imitation. |
| emerger | Emerges in the surface film in the middle of the day, and in cold water it emerges slowly enough that trout take the stuck dun in preference to the free one. |
| dun | Small and dark, riding low. On a bright April afternoon the rise forms are gentle and the fly is easy to lose track of at fifteen yards. |
| spinner | Evening fall, clear wings, dark body. Less concentrated than the Hendrickson's and often overlooked. |
4 patterns in this book imitate the Blue Quill, 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.
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.
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.
Same family, or overlapping this one's calendar on the same water.