about 7mm long.


if you are giving the name what is the key that helped you identify it?

No key Pom ~ engraved on my brain. VLUU-NV7 resolution won't allow wing trailing edge vein definition. Defo not spurwinged though; I'll go male sub-imago of Baetis scambus although the example isn't quite as dark as I'd hoped or a smallish B. vernus - Medium olive. The eyes have it.

__________________


Save the softmouth trout

I'd go with Empheralla - the Small Dark Olive.

FBA Scientific Publication No. 47 (1983)

I’ve removed this image because of unauthorised use after it had been downloaded from the forum – all my images bear a copy-right signature so they clearly should not be used without having first obtained permission. I’m disappointed to have to do this but feel I don’t have much option.

Ok heres another view

does that confirm what you think?

these where about too Body length 5mm, I cant see the rear wing and havent picked it up on any photo so I cant work out if its; B. scambus or B. bioculatus

Pom
The Pale Watery B.bioculatus has been renamed it is now B.fuscatus.

The dun (sub imago) in your latest post has reddish eyes and at 5mm is almost certainly a Small Dark Olive (B.scambus). But I would need to see the double intercalary veins in the forewing and a hind wing to be 100% sure. But I'm pretty certain it's not a male Pale Watery as the eyes would be lemon yellow.

The spinner (imago) in the last photograph is female and for B.scambus and B.fuscatus(bioculatus) they are impossible to tell apart

Single intercalary veins in the forewings would indicate a Spur Wing, a Pale Evening Dun, a Pond or Lake Olive; at 5mm I'd guess it would be a Small Spurwing (Centroptilum luteolum).

Hope that helps

OB

I'd also spotted the single intercalary veins but OB veat me to it as I faffed about looking for the scanned drawing below which explains all. Wing type 'B' therefore: Centroptilum luteolum.

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Save the softmouth trout

that was a really useful key on the intercalary viens I hadnt picked up on.
wouldnt it be great if all these sources were combined in one book.
So the Quest Now is to photograph Mrs SDO of the Brook.
Mayflies have just about packed up after a week of appearance (compared to a month last year).
It seemed like a population explosion this year, but maybe the hot turn after a very cold few weeks , forced them all through in a short burst... i wait to see if a second flush comes through if the weather warms up.

Next on the list of What the ****?
Its got stripy eyes.


I have gota feeling that this is MR but realise its not worth saying anything on these threads until the experts have been for a visit.

Hi Pom

Could they be Electrogena affinis?

OB

Please tell me more? I have no idea.

Its in a back garden pond near the Chelsea and westminster hospital,
I have seen it hatch each year for about 3-4 years and just thought it was a pond olive, To be honest i am usually there working out whats wrong with the plants and not studying insects unless theyre eating the Trachelospermum and I am wondering how to kill them, so i wasnt taking much notice.
Then i photographed it and decided to look a little closer. Its a new specie to me. Cant find Keys for Electrogena affinis in my books.However from what i have seen from the web its a long way from where its been sighted previous.