A very attractive and rather variable fritillary, usually (but not always) found at altitude. It is easily recognised because the uph black/dark brown almost completely smothers the orange, reducing the orange to a series of disconnected spots mainly in the submarginal and post-discal areas. Darker specimens can look quite black in flight. It can vary in terms of size and shape, it seems to me, and can often be quite small.

The underside is characterized by the post-discal series of marks having (usually) a black spot and dark edging, although 18436 is obviously an exception.

One identification clue, that seems consistent, is that the marginal band is filled yellow which contrasts with the bands either side of it.

The subspecies vernetensis flies in the Pyrénées-Orientales and in Ariège and adjacent areas, which resembles Heath Fritillary (M. athalia) more than nominate diamina. It is not clear whether vernetensis replaces nominate diamina in these regions. If diamina flies in these regions, must it then be vernetensis or can it fly in company with the nominate form? Either way, where are the broad boundaries for vernetensis?

From an underside view alone, the unh yellow-filled marginal band is indicative of diamina vernetensis rather than athalia, and the black spots (rather variable in size and shape) in the unh post-discal spaces would tend to confirm diamina vernetensis, although the usually-reliable illustration in T&L shows this series with an absence of black spots.

From the upperside view, vernetensis resembles athalia quite closely and is probably undistinguishable from the general markings alone, except that the upf discal s2 mark is said (by Lafranchis) to resemble a dumbbell, but in his later Lafranchis ID book, he describes it as a club-shaped spot. I would describe as an old-fashioned key or even a fish skeleton. Either way, it is different to the athalia mark here, but the uncertainty is compounded by the illustrations in T&L of both nominate diamina and vernetensis of this mark as a smudge with almost no definition.

As such, this mark resembles, if not being identical to, the mark of nominate diamina, although even here the mark can vary from clear-cut to requiring a certain amount of imagination to see the key/skeleton.

I am still no clearer as to what characterises vernetensis as there seems to be very little information available on the internet. Is it the case that the underside looks like nominate diamina, quite variable, but 49186 being within range, and the upperside looks like 03-10A as above?

observations

a VERY dark male, although the dark uph is set off by the white margins.

a quite heavily marked male, although not quite in the same league as 12775.

this shot was taken in the Pyrénées and I think it must be diamina vernetensis as it matches the illustration in the Lafranchis ID (see comments above). That, in itself, would not be conclusive, given the high degree of variation of this genus, but it is supported by the characteristic upf discal s2 mark, which effects confirmation.

a female, larger and generally lighter than most males. It looks very much like a dark athalia although on balance I believe it to be diamina.

a male, in which the unh post-discal spots are faint unfilled circles rather than the solid black dots normal of diamina. The general colouring is unusually sandy yellow over the entire surface of the unh, especially the discal series (contrast with 25770).

a female underside, the dark-filled unh post-discal lunules being typical of diamina.

This is clearly a female from the body shape. I originally - and erroneously – had this labelled as Provençal Fritillary (M. deione) and had it temporarily on the page for deione. It was there because it was flying in company with deione and appeared quite red, usually an indicator of deione. It didn’t, however, look right for deione for several reasons and I commented to this effect when I originally posted it. I did wonder about diamina but the low altitude (620m) deterred me as I had never seen diamina at less than around 1500m except one or two spots at 1100m where it comes down to takes salts from the ground. Thanks to Tim Cowles for pointing out the correction.