Hatches Made Easy:

Little Yellow Quills (Heptagenia Group)

05/12/08

There is a group of mayflies from different genera within the Heptageniidae
family that are lumped together under the title "
Heptagenia Group". The three
genera included in the group (
Heptagenia, Nixe and Leucrocuta) are very
closely related.
There is a very common two-tailed, yellow mayfly that starts to appear in late
summer in the Great Smoky Mountains National Park that I have not been able
to positively identify. In fact, I think there may be more than one species of them.
I have not taken the time to try to determine the species from keys under a
microscope.
The clinger nymphs of these mayflies are very common in the smaller brook
trout streams in the higher elevations. You can find the duns and spinners in
very plentiful quantities at times.
If you consider the number of them on the
water on a square yard basis, they would compare to the Quill Gordons
or other larger hatches in the Smokies.
They also occur in the lower
elevation streams but they don't seem to be quite as plentiful as they are in the
streams at higher elevations.
One reason I am convinced there is more than one species is the fact you will
find them for several months starting in late summer ( we show the 3rd week of
August) and continuing as late as the first week of December depending on the
weather. Also, there seems to be some minor differences in the ones I have
closely examined. I don't think any of the differences I have noticed has anything
to do with their behavior and certainly are not different enough to require
different imitations or flies. Most anglers I have asked thought these mayflies
were "Light Cahills" but they are not
Stenacron or Stenonema species.

These are the species listed for the park but I would make a friendly bet that
there are more of them.
Heptagenia julia
Heptagenia marginalis
Leucrocuta thetis

The "Little Yellow Quill" is the common name given to several species of the
Leucrocuta genus of mayflies that are fairly common in many Eastern streams.
One thing for sure is that the name "Little Yellow Quill" certainly fits the ones in
the park. At least they look very much like the pictures of the mayflies commonly
called Little Yellow Quills and I am fairly certain they are at least in the same
genus.

Note:
If anyone has any additional information regarding these mayflies, I would
appreciate you letting us hear from you. We receive email almost every day and
usually several per day regarding the "Hatches Made Easy" articles. Even
though we cannot possible respond to all of it, we do appreciate it.

Coming Up Next:
Little Yellow Quills - (Heptagenia group) - Nymphs and Emergers

Copyright 2008 James Marsh