Pale Evening Duns
.............................Fly Fishing Yellowstone National Park
08/11/08

Pale Evening Duns:

Pale Evening Duns can be an important mayfly to imitate on some of the streams in
Yellowstone National Park. It is not a huge hatch but on the streams where it does exist
it is important because if hatches at a time there are few other mayflies hatching. Most
of the stonefly hatches have occurred and there may not even be many caddsflies on
the water.
The Pale Evening Dun is in the
Heptagenia group of mayflies. The Heptagenia solitaria
species that exist in the West is usually called the Gray Fox. The other species, mainly  
the
elegantulata species, are usually called Pale Evening Duns. Although they almost
never hatch in prolific quantities, they may be found in just about all of the streams at
all elevations. We know they are found in the Yellowstone, Lewis and Gardner Rivers
but we have not checked specifically for the mayflies in other stream samples we have
taken.