Slate Drakes – aka “Isonychias”

Fall fishing is a time of year when aquatic insect activity is minimal compared to the spring hatches. Therefore any hatch activity at all is usually met with anticipation and eagerness by the trout. Oftentimes windy weather and or rain will dislodge terrestrials from trees and bank-side vegetation; these include inchworms, ants, beetles, crickets, grasshoppers, bees, caterpillars, and spiders. This activity can be sporadic, heavier at some times than others from resulting conditions; consequently autumn dry fly fishing with terrestrial patterns can be effective. Beetles, ants, and my original Floating Inchworm pattern are my fall favorite terrestrial patterns. Among the buffet of terrestrial activity, there are still a few aquatic insect fall hatches that we anglers can take advantage of. One of my favorite mayflies in the spring, the Slate Drake, or Isonychia bicolor, also begins to emerge in the fall as the second brood of this species begins to hatch in mid-to-late September. Common in the Eastern United States on freestone waters, Slate Drakes can run almost to the end of October, often providing a near-exclusive aquatic insect match-the-hatch, dry fly fishing opportunity.

Floating Inchworm - extended body designed and tied by Don Bastian. The hook is a #16 Tiemco 2488, short shank,wide gape. This is a great fall terrestrial searching pattern.

Floating Inchworm – extended body designed and tied by Don Bastian. The hook is a #16 Tiemco 2488, short shank, wide gape. This is a great fall terrestrial searching pattern.

The first hatches of Isonychia bicolor in spring begin as early as mid-may and continue through July, sometimes sporadically, but there can be periods when these large, dark, slate-and-brown colored mayflies emerge in fairly heavy numbers, inciting trout to feed vigorously on the emergers and duns. The Slate Drake Spinner is also a significant element of this hatch and should not be overlooked. Typically these nymphs migrate to the shallows, but the nymphs living in large streams and rivers far from shore simply emerge from the water when their hatch time is ready.

A Slate Drake dry fly pattern in various styles is a good dry fly searching pattern whenever they are in season, but they are especially good in the fall when competition from other hatches is not as intense as the spring and early summer. Some traditional Slate Drake dun patterns include the White-gloved Howdy and Dun Variant. I like my BXB (Bastian Extended Body) Slate Drake Thorax Dun, Parachute, and Spinner patterns better than any other pattern style for this hatch. I’ve been fishing these patterns for nine years with wonderful success. Below is a photo of my BXB Slate Drake Thorax Dun pattern, still wet after it was removed from the jaw of an eighteen-inch brown that confidently took it on Big Pine Creek in May of 2012.

BXB Slate Drake Thorax Dun pattern. The hook is a size #14 but the fly is actually what would normally be considered a #8 or #10.

BXB Slate Drake Thorax Dun pattern. The hook is a size #14 but the fly is actually what would normally be considered a #8 or #10. The length of the pattern not including the tails is a good 3/4″ to 7/8″ in length. This fly was knotted to 4x tippet because I was fishing a fairly heavy riffle section, and I expected to encounter big trout. I did!

And here is a photo of that trout:

18-inch brown trout taken on my Extended Body Slate Drake Thorax Dun pattern, Big Pine Creek, May 2012.

18-inch brown trout taken on my Extended Body Slate Drake Thorax Dun pattern, Big Pine Creek, May 2012.

Here is a nineteen-inch brown I took fifteen minutes after the fish shown above:

19-inch brown taken on Big Pine Creek,May 2012, on my Slate Drake Thorax Dun pattern.

19-inch brown taken on Big Pine Creek, May 2012, on my BXB Slate Drake Thorax Dun pattern.

This article started off with the intention that it would be only about Slate Drake nymphs, but it obviously morphed into a work to also include dry fly patterns. These insects are large, often requiring size #8 hooks. That size may sound too large to some anglers, but if you consider the actual body length of a Slate Drake dun and compare it to the shank length of a standard dry fly hook, that’s what you would need to use. Too many fly anglers dislike large drys; they don’t know what they are missing by not using them. Large imitative or attractor dry fly patterns like the Fan Wing Royal Coachman or Royal Wulff can really stir up some excitement on the water. I’ve read the words of some writers who say that the fall Slate Drakes are as small as a size #14, but I personally have never seen a Slate Drake that small in my life. I would not tie this pattern smaller than a size #12 standard hook length for fall fishing, and I have full confidence fishing my large extended body patterns that imitate the spring hatches of the Slate Drake. Though I generally dress them on a #14 Tiemco 2488 hook, these flies are the equivalent size compared to a standard dry fly pattern in a size #8 or #10. Some of the same line of thinking by other fly tiers and anglers expresses surprise at my devotion to size #14 Sulfur patterns for Spring Creek, when most other anglers fish #16’s. Heck, I’m just imitating the actual size of the bugs I see on the water. And it’s not that #16 Sulfur dry flies don’t take trout, but a larger fly is easier to see under most conditions, and floats better. Most importantly, it works!

Here are two similar Slate Drake nymph patterns; the first one was tied by my friend Bill Shuck, of Jarretsville, Maryland. Below that are photos of the same pattern that I tied. Bill made a couple modifications because he did not possess all the same materials that my recipe calls for.

This is essentially the Slate Drake nymph pattern conceived by my friend Dave Rothrock, but I made a few modifications to it in the interest of making it tie easier and faster.

Slate Drake Nymph - tied and photographed by Bill Shuck.

Slate Drake Nymph – tied and photographed by Bill Shuck.

Here’s a side view:

Side-view - note the bulge of the wingcase proflie

Side-view – note the bulge of the wing case profile. This is Dave Rothrock’s pattern design, with some tying modifications, but the use of poly yarn for the wing case is Dave’s accurate material usage to simulate the natural high wing-case profile of the Isonychia nymphs. This imitative design is a “strike-trigger” to the trout. Tied and photographed by Bill Shuck.

Isonychia / Slate Drake Nymph – Bill Shuck version

Here is Bill’s list of materials in order of tie-in::

Hook: Daiichi 1760, Size #10
Thread: Uni-Thread 6/0, black
Tail: Three natural grey ostrich herl strands, trimmed short
Rib: Pearsall's Gossamer silk thread, brown, doubled and twisted
Median stripe: Uni-Thread 6/0, white, doubled and twisted
Over Back: Medallion sheeting, dark dun
Abdomen: Blend of hare's fur, 50% claret/25% brown/25% black
Wing case: Black poly yarn, two strands
Thorax: Same dubbing as abdomen
Legs: Badger hen cape feather barbs

Bill wrote me in his e-mail with the recipe: “All typed out like that it seems like too much stuff to
bother with, eh?”
To which I replied, “Not when you consider how well this pattern works. The extra tying time 
pays off."

Today, Monday morning, two days after I initially published this article, Bill sent me another 
Isonychia nymph pattern, this is the same fly with the addition of a single strand of natural ostrich
herl wound as a rib. 
Isonychia nymph variation - tied with natural gray ostrich herl gills. Tied and photographed by Bill Shuck.

Isonychia nymph variation – dressed with natural gray ostrich herl gills. Tied and photographed by Bill Shuck.

Slate Drake Nymph - tied and photographed by Don Bastian.
Slate Drake Nymph – tied and photographed by Don Bastian.
Slate Drake Nymph - top view

Slate Drake Nymph #10 – 2x long – top view. Tied and photographed by Don Bastian.

Isonychia / Slate Drake Nymph – Don Bastian version

Hook: #10 - 2x long nymph hook, or 3x long TMC 200R or Dai-Riki 270
Thread: Danville Flymaster 6/0 #100 Black, or #73 Dark Brown
Tail: Three fibers of natural ostrich herl
Median Stripe: Danville Flymaster 6/0 #1 White
Ribbing: One strand of Uni-thread 6/0 Dark Brown
Overback: Black scud back 1/8”
Abdomen: Haretron Dubbing #16 Dark Brown
Gills: Abdominal dubbing picked out and trimmed parallel to body.
Wingcase: Black polypropylene yarn, two strands
Thorax: Haretron #16 Dark Brown
Legs: Natural mottled hen back, short and sparse
Head: Black
The main design of this pattern goes to my friend, Dave Rothrock, guide, and fly tier, from Jersey 
Shore, Pennsylvania. He uses a stripped cream hackle feather for the median stripe; the use of
thread is obviously a huge time-saver. I also use ostrich herl strands from anywhere along the 
stem, Dave uses only the tips, which are limited in number on any feather or bundle of ostrich
herl. I can make several sets of tails from just three strands of ostrich. I cut the tips at an angle with
my scissors, trimming only the outside edge of the barbs.

I also chose to change the dubbing to Haretron; my reason is that the increased density of fine fibers – 
under fur and the Antron – makes it easier to pick out the gills. Dave’s use of poly yarn for the wing 
case is a stroke of genius in imitative pattern design. Its bulk simulates the natural profile of the live
nymphs. This is a trigger-point for the trout and significantly contributes to the inducement of strikes,
if not being the primary reason that trout take this pattern with voracity.
Below is a photo of my Slate Drake Parachute Dun:
Don Bastian's BXB Slate Drake Parachute Dun.

Don Bastian’s BXB Slate Drake Parachute Dun.

Any of these pattern can be ordered by visiting my product pages at MyFlies.com: http://www.myflies.com/BXB-Slate-Drake-Set-P741.aspx

or the Slate Drake Nymphs may be ordered by visiting my Custom Order page: http://www.myflies.com/Don-Bastians-Custom-Fly-Orders-P750.aspx

If you get a chance to venture out for some fall fishing, most streams in the Eastern United States have Isonychia populations – be prepared, and have some of these patterns to fish with.

I meant to include these photos yesterday when I wrote this post…the wordpress format was having “issues,” giving me technical difficulties, and I forgot. Here is a soft-hackle Slate Drake Flymph tied and photographed by Bill Shuck:

Isonychia Flymph - tied and photographed by Bill Shuck.

Isonychia Flymph – tied and photographed by Bill Shuck.

Here is the recipe for this pattern:

Isonychia / Slate Drake Flymph

From Bill: “This was a pattern that I posted on the Flymphforum in April 2012. The vintage hook is one given to me be a friend in Virginia, and the European hare dubbing was dyed by another friend who lives in Holland, the same guy I hosted for two weeks this past spring and who gave me an excellent 5 wt. bamboo rod he made himself.

Hook: Vintage Mustad 3913B. Size #12

Thread: Pearsall’s Gossamer silk thread, #14 claret

Hackle: Medium dun hen saddle

Tail: Three moose body hairs

Body: European hare dyed claret, spun in a dubbing brush with claret silk thread

Nice that you got a bamboo rod for hosting your friend! Such a deal!

I close this with image of a half-dozen Slate Drake Nymphs:

Slate Drake Nymphs, tied and photographed by Don Bastian.

Slate Drake Nymphs, tied and photographed by Don Bastian.

And one final shot, lined up in a row:

#10 3x long Isonychia - Slate Drake Nymphs. Tied and photographed by Don Bastian.

#10 – 3x long Isonychia – Slate Drake Nymphs. Tied and photographed by Don Bastian. These are dressed on Montana Fly Company Curved shank straight eye nymph hooks, #7002 Stimulator Hook.

12 comments on “Slate Drakes – aka “Isonychias”

  1. Aaron Marzec says:

    Wow… Love the nymph!

  2. Don Bastian says:

    Hi Aaron;
    Thanks! This pattern is actually the most imitative mayfly nymph that I tie. But fishing it proves that it is well worth the extra attention to detail. Thank you for your comment!

  3. Kelly L says:

    I liked the blog today Don. I guess you know you are partially responsible for the decrease in my funds. I started buying DRY FLY capes. Yes, you read that right. I couldn’t believe it myself. I have actually been tying a few.

  4. larry pauley says:

    DON I Have BEEN Using BIGGER DRYS INSTEAD OF All THE SMALLER ONES THEY WORK BETTER FOR ME HERE NC MT. NEXT TIME IN PA WOULD LIKE TO TRY TO MEET YOU.

    • Don Bastian says:

      Hi Larry;
      Good to hear that someone else likes big drys! You know what I meant though, so many people are always thinking “small flies.” It would be great to hook up when you visit Pennsylvania…just let me know. Thanks for your comment!

  5. Darin Clapp says:

    Love that Flymph pattern. Do you think Claret seal fur would be as effective as Hares fur for the body?

  6. Don Bastian says:

    Hi Darin;

    Thanks for your comment! I’m glad you like Bill’s Flymph, he does a great job on those, and his photos are also good. I’m sure claret seal fur would do equally as well as the hare’s fur on this pattern. Thanks again!

  7. Beautiful series of flies. I am a big fan of ISO patterns, and look forward to trying these.

  8. Bruce says:

    Hey Don! Have you ever posted the pattern for your Iso Extended Body Dry? I bet I could use a few this Monday.
    Bruce

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