Hook: Size #8, #10,
or #12 nymph hook. Jennings used both
sproats and snecked hooks, but a 1 x-long or 2 x-long hook will work.
Tying thread: Black, 6/0.
Tail: Tips of a Partridge feather. (You can also substitute with Pheasant Tail
fibers, but my favorite tail is 3 Peacock Sword
fibers.)
Rib: Round gold tinsel.
Abdomen: Seal’s fur (or substitute) dark red and plum, mixed.
Thorax: 2-3 strands ofPeacock
herl.
Hackle: Furnace cock hackle, two to three turns.
Preston Jenning’s Isonychia Nymph Variation
Hook: Size #8, #10 or #12 nymph hook.
Tying thread: Black, 6/0.
Tail: 3 fibers of Peacock Sword.
Body: Seal’s fur (or substitute) dark red and
plum, mixed. (There is no Peacock Thorax or rib on this version).
Hackle: One to two turns of grouse for the hackle.
This
is a very traditional and old trout pattern.
Tie and fish it and you’ll be stepping back into Fly Fishing
History. It was developed by a fly
fisher named Preston Jennings. In his
day, Preston Jennings was a very well known fly fisherman and tyer. His book “A Book of Trout” was published in
1935. It was the first comprehensive
guide to the insect life that trout feed on and the patterns that would emulate
them. The book was the first of it’s
kind back then and the gold standard by which future books would be
measured. Jenning’s home waters were Catskill Rivers,
especially the Esopus Creek. He was one
of the most innovative fly tyers of his time.
Isonychia
Nymphs are not like other mayfly nymphs which seek cover on river bottoms. They are active swimmers. Often darting from rock to rock even in fast
water. What’s great about fishing these
nymphs is their larger size. Also, their
availability from May into October.
Jennings
tied his iso nymphs in a couple of different ways and materials. I like to tie his ‘traditional’ pattern and
tie a lot of them with peacock sword tails (a component of his variation). What’s great about fly tying is experimenting
for what works best for you.
Begin
by starting your thread an eye length behind the eye. Wrap down to the bend of the hook. Tie in approximately 6-8 fibers of Partridge,
about a hook gap length. (You can also
substitute with Pheasant tail or Peacock Sword fibers.) Next, tie in your gold rib. You are now going to dub a body of seal or
similar Isonychia prepared dubbing.
Begin at the bend of the hook and dub forward leaving enough room behind
the eye for your peacock thorax (about an eye’s length & ½ space). Wrap your rib forward making even spiral
wraps. Tie off your rib and cut off the
tag end of it. Tie in 2-3 stands of
peacock herl for your thorax. Wrap the
herl for your thorax. Approximately 3-4
wraps is all you will need. Make sure to
leave enough space for your hackle. Next
tie in your hackle. Make 2-3 turns then
tie and trim off. Form a head to the
nymph with your tying thread. Whip
finish and trim off your thread.
Finally, apply head cement to the wrapped head.
Tim Flagler of Tight Lines Fly
Fishing has an excellent instructional video on how to tie this fly below:
How
to fish this fly – You
can fish it as you would any other nymph or you can swing it like a wet
fly. One thing you have to do is to
occasionally twitch the fly. This is a
deadly technique on the Catskill streams and it works very well on the
Farmington & Housatonic. You can
twitch it with your rod tip or the way I do it, I’ll give it some short fast
strips with the line. As I said earlier,
Iso’s are great swimmers darting from rock to rock. My greatest success has been in the faster water
with this fly. If you have any questions about this fly or would like to submit a Fly of the Month, I can be reached at 203 305-3850 or pdinice@frontier.com .
