Hatches Made Easy:

Eastern Pale Evening Duns

03/25/08

The Eastern Pale Evening Dun (Ephemerella
invaria
) is another mayfly that is often confused
with the Sulphur
. This is just another example of
common name confusion and the main reason
scientific names are used. Of course there is
no "right and wrong" common name but I will agree with most authors that the
Ephemerella dorothea is usually a "sulphur" color whereas the Ephemerella
invaria
is usually a yellowish tan color.  The only good thing about this confusion
is the fact that there is little difference in the species. The Sulphur is slightly
smaller than the Eastern Pale Evening Dun. The Sulphur is usually found in
slower, more moderately flowing water than the Eastern Pale Evening Dun.
Imitating the two species requires different presentations in many cases. The
Eastern Pale Evening Dun usually hatches about two weeks earlier in the year
than the Sulphur.

You will find that the Smoky Mountains National Park has relatively few of these
mayflies as well as the true Sulphur. Both are crawler nymphs that prefer slower
moving, calmer water that you find in short supply in the Smokies. Even so, there
are many areas of the park's streams where the Eastern Pale Evening Dun
hatches in good quantities. It is a mayfly that you will want to be able to imitate if
you encounter a hatch.

Coming Up Next:
Eastern Pale Evening Dun - Nymphs and Emergers

Copyright 2008 James Marsh