Hatches Made Easy:

Cream Cahills - (Maccaffertium species) - Nymphs and Emergers

03/22/08

The Cream Cahills are difficult to describe. They are also very difficult to tell apart in
the field. The colors can vary from stream to stream and species to species. As you
can see below, there are several species that fall under the common name "Cream
Cahill".
The nymphs are very similar. They are almost impossible to tell apart with a
microscope. The duns, however, can vary in appearance quite a bit. The shade of
color of the wings, bodies, and other body parts varies from species to species.
Basically, they all have a cream, creamy white to beige body with a darker thorax.
They all have pale gray wings but the markings, if they have them, will vary.
Like most clinger species, the spinners are usually the same as the duns except the
wings become transparent and the front legs and tails become much longer. The
bodies usually become darker and change towards a brown or rusty color.
These are the known species that exist in the park. The
ithaca species can look as
much like a Light Cahill as a Cream Cahill.

Stenonema integrum (Now Maccaffertium mexicanum integrum)
Stenonema ithaca
(Now Maccaffertium ithaca)
Stenonema mediopunctatum
(Now Maccaffertium mediopunctatum mediopunctatum)
Stenonema meririvulanum
(Now Maccaffertium meririvulanum)
Stenonema modestum (Now Maccaffertium modestum)
Stenonema pudicum (
Now Maccaffertium pudicum)
Stenonema sinclari (
Now Maccaffertium sinclari)
Stenonema terminatum (
Now Maccaffertium terminatum terminatum)

It is very possible that some of these have recently been reclassified. I have not had
time to check that out. It makes no difference in so far as anglers are concerned.  
Update: 3/24/08:
As expected, I discovered that most of these have been moved to the Maccaffertium
genus. I am not sure about the ones still shown as Stenonema. I am revising the
above list.
Update: 3/25/08:
Revised list again to show all changes.

Nymphs:
As I mentioned above, there is almost no difference from species to species in the
appearance or behavior of the nymphs. They are all flat clingers that are brown to
dark brown with amber legs and tails. Like all clinger nymphs, these move from the
fast water they live in to nearby, slower water to hatch.
The big difference is the Cream Cahill nymphs hatch on a more irregular basis than
the closely related March Browns or Light Cahills. They are found in isolated areas
of the streams they exist in. By the way, they are found in most all of the streams in
the park but they are always scattered about the stream in a very inconsistent
manner as best I can determine. The Light Cahill are fairly consistent throughout
the park but the Cream Cahills are scattered about in isolated locations.
Our stream samples show that a large area of a stream may not contain any, yet
another area that appears identical  may have plenty of them. The bottom line is
that you never know when or where to anticipate a hatch.  You just need to be
prepared in the event you find them hatching.

Nymph Presentation:
Nymph presentation should be exactly like the previous article on Light Cahill nymph
presentation

Emergers:
It appears to me that most of these species in the Smokies hatch in the evenings. I
have not found many newly hatched duns. It seems you just discover the duns on
the stream and never see them hatching. I would assume they hatch in the surface
skim like but I do not know for certain. Most of the fly fishing books I have (which is
all of them as far as I know), say they hatch in the surface skim. Although I am
appreciative of the work and effort put forth by most of the writers, I have discovered
many errors that have been put in print as well as differences from one book to the
next. The Cream Cahill clingers are difficult to raise in an aquarium and I have not
seen them hatch.   

Emerger Presentation:
Since I haven't found them hatching, I have not tried the emerger patterns for the
Cream Cahills even though we have both a emerging nymph and trailing shuck
"Perfect Fly" pattern for the emergers. I wish I could be more precise and offer more
advise but I cannot at this time.
I am most interested in hearing from any of you that can add to this stage of the
Cream Cahills.

Coming Up Next:
Cream Cahill Mayflies (Maccaffertium species) -Duns and Spinners

Copyright 2008 James Marsh