For comments on the taxonomy of the Boloria group please see the page for the Balkan Fritillary (B. graeca). Napaea is very similar to the Shepherd's Fritillary (B. pales) and quite difficult to differentiate, especially as they often fly together at high altitudes. The female napaea is strongly suffused with a greenish sheen and quite different to the female pales. The key differentiating features of the males of these two species appear, from what I have read and observed, to be:

1) black markings: napaea has (allegedly) somewhat finer upperside black markings. However, the Alpine subspecies of pales is palustris, in which the black markings are narrower and the colouring redder. This rather negates the value of the fineness of the markings with regard to differentiating the two.

2) upf marginal markings: Lafranchis says that the upf post-discal and submarginal spots are broadly parallel from s1b to s6 for napaea, whereas for pales they are closer in s4-s6 than they are in s1b-s3. This may sound complicated, but it is the best means of differentiating between the two with any degree of confidence, and it does seem to work. It also seems to me that the napaea submarginal markings on both wings are rather more sagittate than pales.

3) undersides: there are some rather subtle differences in the shape of the underside markings, especially the unh. The white markings of pales seem more pronounced. The unh needs to be checked carefully against the illustrations in T&L. This seems to work quite well, and corroborates other identification clues.

4) wing shape: Lafranchis says the pales forewing is elongated and narrow and pointed at the apex. The napaea forewing is described as very broad.

5) distribution: both are local in the Alpes and Pyrénées, although Lafranchis says pales is widespread and abundant, where napaea is localised but abundant enough in the Alpes and probably restricted to the eastern part of the Pyrénées.

6) altitude range: according to Lafranchis, napaea is found only at high altitudes of 1800m and above, while pales has a normal altitude range of 2000-2500m but can occur as low as 1600m. Lafranchis says that where they fly on the same mountain, pales often flies at higher levels than napaea.