After looking at a lot of Heath (M. athalia), Meadow (M. parthenoides) and Provencal (M. dejone) Fritillaries I think I may be able to tell them apart, but I’m sometimes less than 100% sure. The dejone male upperside ground colour is clear orange-yellow with thin black markings, consistent in the male, but the female often has paler bands giving a colour contrast, clearly visible in 10439. I tend to feel that the marginal lunules are more arched and arrow-shaped in dejone than in it's relatives, but this may not be conclusive, or even indicative.

The underside has a reddish feel to it, often with a clear reddish spot in each post-discal space. In some textbooks dejone is spelt deione.

In the new European taxonomy, the Mellicta fritillaries are now grouped with the Melitaea genus, so this species now has the scientific name Melitaea dejone.

observations

a male, in typical territorial pose.

an unusual opportunity to compare the two uppersides, the female being on the left. The male is more typical of the strong orange-red colouring than 10475.

a shot of courtship, the female above, I think. 

a typical female, showing the unmistakeable colour contrast that leave little room for doubt that it is dejone.  

The red spots in the unh post-discal spaces are rather small, whereas they are usually red-filled, but the strong redness of the unf is usually a good indicator of dejone. I find it hard to get opportunities to photograph the underside, hence this rather old photo. However, Tim Cowles points out that the unh marginal band is yellow and contrasting with the adjacent white, which conclusively indicates athalia. The black shadow to the unf marginal lunule in s2 strongly indicates athalia. I think the redness may be a factor of the film camera I was using at the time, which often enhanced colours sometimes unnaturally. Athalia it is, then, but I'll leave it on this page to invite further comment on dejone/athalia ID features.