This is very similar to the High Brown Fritillary (A. adippe) and the Dark Green Fritillary (A. aglaja), although niobe is usually slightly smaller. For the principal differences based on an upperside view, see the adippe and aglaja pages. The undersides of each of the three species are different and more easily easily distinguishable than the uppersides.

In the niobe underside, which is superficially similar to adippe, the veins  are usually lined black and there is (allegedly) usually a small black spot within a small lighter spot near the unh base (see illustration below - although the black spot is usually larger than this), although in the far south of France niobe is rarely seen with the famed black spot. Indeed, every specimen seems to be of the form eris, which appears to be predominant in the south. Eris is usually lacking the unh black lines, which seems to contradict the descriptions in most of the text books which state/suggest that the black lines are characteristic of niobe.

At high altitudes, I have sometimes found rather dark forms of niobe, as illustrated by some on this page.

Niobe is an early emerger compared to adippe and aglaja, appearing in May. It is also seems to a more southerly distribution whereas adippe and aglaja do not seem to occur in the far south of Var on the Mediterranean coastal regions.

observations

a male, a slight aberration shown by the rather heavy black markings in the discal and post-discal region. This has been a common feature of 2010, as noted elsewhere, perhaps because of the cold and damp early spring weather.

I suspect this is a male niobe (rather than aglaja) based on the slightly lighter markings especially around the uph basal area and the marginal uph marks which are more crescent-shaped but more solid in aglaja. However, that post-discal uph spot is s4 looks heavy for niobe and suggests aglaja, but the very small spot in s6 is a strong indicator of niobe. The sex brands on upf v2 and v3 are quite slender but enough to confirm male, along with the body shape.

a very fresh male, the orange colouring is very rich.

a typical female, quite large and with a slight sheen across both forewings.

a very dark female, judging by the body length and shape and behaviour. 23227 is the underside. It is the underside that confirms niobe, as I would not be confident of an ID based on the upperside alone.

I suspect this is a male, based on what I could recall from seeing the upperside. The unh is a beautiful blend of beige and pale orange, with (unusually for the specimens I see in the far south of France) black edging to the markings, which adds to its appeal. The famed basal black spot is absent, but it is just possible to see two black pin-pricks within the yellow spot. It is the southern form eris.

a female, the underside of 23232 above. Although it is rather dark and diffuse, it is still very attractively marked.

a rarity! A female with a clearly visible, if still small, black spot. Curiously, the veins are not lined black, in contrast to 6360 which has black veins but no black spot.

a rather dark niobe, possibly female based on its behaviour. The colouring is about halfway between typical 11621 and the high altitude 23227.