I often see references to this "class" of up-wing fly in US fly tying books yet there's nothing in Goddard's Waterside Guide with this term (unless I missed it). What's the UK equivalent? The reason I ask is that I was on the Test yesterday and there was a large hatch of very small up-wing flies that upon getting home and finding my Waterside Guide (which obviously isn't much good as a waterside guide if you leave it on the book shelf) I think were either Small Dark Olives or Pale Wateries. It would seem to me that flies called PMD would be a good imitation. Yes? No?

Hi', Steve. Four of the small olives have a flight period that takes them through October, weather conditions permitting. Iron Blue Dun and small Dark Olive are the dark pair. Pale Watery and Small Spurwing are the light pair. PW or SS can be copied with very simple patterns, and a popular up here in Cumbria, especially in the Carlisle and west of the county areas, is a Badger and Yellow. I find a Grizzle and Yellow just as effective. Yellow tying thread or body, tails of several strands of hackle barbs/fibres, grizzle cock hackle at the shoulder. Some anglers would recommend Tup's Indispensable.
For a wet fly, try Snipe and Yellow, Starling and Yellow or similar.
Up here, we used to get good hatches of the light pair bringing up the grayling in October. Iron Blue and Small Dark Olive were not as common after the end of summer. Might be now due to climate change!! TerryC

Thanks Terry. The Small Dark Olive female dun looks rather light in colour in the photo in Goddard's book. Is this just the photo printing?

I will take a look at the Badger and Yellow. BTW take a look at the post I made in thefly tying section: Small Dark Olive/Pale Watery Dun It was interesting that the trout took a good look at the Tups Indispensable but then gave it a sharp rejection. It was the only thing I had with a pale yellow body and so I ended up switching to nymphs. What's the rationale behind the pink in a Tups Indispensable?

In addition to your Badger and Yellow I will also tie up some PMD Barr Emergers and PMD Barr Vis-a-Duns.

I'm just disappointed to be one step behind the curve. A day on a chalkstream is a big expense for me and while I had a full bag I missed the magic of a dry fly session matching a big hatch. I had one brown on a Klinkhamer, one on a Rusty Spinner and, surprisingly, my last on a Golden Stimulator late in the day but they all felt "lucky". (The Rusty Spinner was chased and slammed.) The balance of the day fell to a Sawyer Killer Bug.

Hi', again, Steve.
Success, consistent success, with dry fly on a particular day depends very much on the weather conditions affecting emergences of aquatic flies.
In warm, bright and sunny weather, especially with a bit of wind, emerging duns may break through the surface barrier of the water -- it is a barrier to them -- and travel relatively short distances while afloat before their wings dry and stiffen sufficiently to support them in flight. The birds of the air just love that, but the trout that have been feeding on ascending nymphs, and the even more vulnerable emergers in the surface water, will have little incentive to make the extra effort involved in taking dries, or relatively little opportunity. On humid days, overcast and, better still, with drizzle in the air, the duns' flight departures are delayed, and you may well find the fishing under such conditions the more memorable of the season.
Such phenomena have evaded my fellow-anglers on the Eden system this year on all but the odd outing. Instead, we have had to rely very much upon daytime terrestrial falls, shade-fishing in the sheltered margins, or upon spent fly falls in late afternoon or evening. I would guess that most of this season's Eden trout have been taken on upstream or downstream wet flies, and medium to heavy nymphs fished under supporting dry flies or floss indicators, or upon Czech-style presentation.
When conditions result in your seeing trout bulging at ascending nymphs and emergers, while duns of the same species are floating over their heads on the same riffles, having travelled down from their native upstream riffle, you are truly blessed with a great day. Make the most of them. It isn't often, these days that dry fly/nymph enthusiasts on our Cumbrian rivers see this happen. Some anglers, 'newbies', especially, may never have seen it.
Cheers, TerryC
PS It was the above special condition that induced me, in the days when the hatches were better, to use a dry fly dropper with a light-weight Greenwell's Glory nymph on the point. Rises could be expected to either fly. Do I fish that way now? No, I just don't get the chance; but I live in hope. That was a style I used mainly thirty to forty years ago. I was lead to believe it was called 'West Country Style', but no one on here has yet confirmed that.

While I can't speak from vast experience on UK rivers, I think this last Sunday was perhaps one of those days. Grey, slightly damp at times but mid warm in temperature (c16 degrees C). Plenty of flies in the air (hundreds if not thousands) and drifting down the river surface. Trout having a relative feeding frenzy for several hours from about 10am. Still, the trout were relatively fussy and as I note above most of my dries were rejected. The one that got the most attention, but still rejection, was the only thing I had with a pale yellow body - the Tups Indispensable. Perhaps it was the pink that turned them away at the last millisecond.

The beat was single fly only otherwise a set-up of a dry trailing an emerger would have likely been quite a combo.

And now I have to wait until next year (and save some money between now and then!)

Hi', Steve.
Regarding the Small Dark Olives, the duns have olive-grey bodies, while both Pale Watery and Small Spurwing duns are generally lighter in body colour. You might need to have one of each in front of you to be able to make a positive identification. With a good magnifying glass you might well see the difference in the hind wings, and eye colours might help, but I would expect trout feeding on any of these three to accept a copy of a Pale Watery dun.
Tup's Indi. is not a favourite with me, but that's just me. If trout were definitely taking natural duns off the top and leaving bubbles, while rejecting your offerings, I would suggest one of three possible causes. The artificial was too large ( a size match is vital ), the tippet was too heavy ( its stiffness influencing the movement of the dry fly on the water ) or something was inducing drag.
Colour would be my last worry, as the duns would be seen in silhouette.
I envy you the sight of a hatch like the one you saw. Best wishes for the grayling season, and for next year's bash at the Test trout. TerryC

Cheers Terry. Thanks for the help. Hopefully if I get another shot at a chalkstream, let alone a hatch such as that one, I'll be more on point as a result of your help!