Fagi or Hermione...

[David M]

Still can't make my mind up on this one.

Woodland or Rock Grayling?

Seen at approx 1,100m in the foothills of the Spanish Pyrenees on 15th July this year:

[Padfield]

I've examined hundreds of set specimens and while there are certain rules that work for most populations, most of the time, there are none that work everywhere, all the time. Size is actually a very good criterion, but it is rarely possible to measure to the nearest millimetre in the field!

That said, I think this is hermione. The eyebrow isn't marked but it does clear the eye in the characteristic arch (in fagi it goes across the top of the eye in a more or less straight, often diffuse, cut); the white band is relatively narrow and shows clear white spots outside it (this is not a good criterion everywhere, as I saw fagi in the South of France with Roger with similar bands - but all my Spanish fagi have broad, chalk-white bands); the white bands are not solid, chalky white (see previous caveat!).

I regard the eyebrow criterion as the best. I discovered it about 20 years ago, after studying dozens of pictures and real-life butterflies.

Examining Julien organs is in my opinion only for experts as to expose them you have to squeeze the abdomen and you risk harming the butterfly.

Guy

[David M]

Many thanks for this, Guy.

I've seen both these species, but never together.

I must study this 'eyebrow' feature rather more.