This is one of two species I find very difficult
to separate - the other one is the Shepherd's Fritillary, C. pales.
There are another 2 very similar species (Balkan and Cranberry
Fritillaries, B. graeca and B. aquilonaris) that further
confuse the situation but these are both relatively uncommon where they
overlap and can be readily separated. See the table for B.
graeca for more information on all 4 species.
Certain females
of napaea are instantly recognisable by the violet mauve sheen
that covers the uppersides. Specimens without this sheen need closer
inspection for proper identification. To separate napaea and pales
it is first necessary to note where they were found. Their ranges only
overlap in the eastern Pyrenees and the Alps.
In
the Pyrenees:
Feature
napaea
pales
Underside forewing black markings
shadows only
clearly marked black
In the Alps:
Feature
napaea
pales
comment
Two rows of submarginal spots
roughly parallel
start converging from space 4
To me it seems the spot of the inner row in
space 4 is displaced outwards making it look like the rows start
converging.
Upper forewing black discal markings
fine
thick
This feature is variable and I'm not always
convinced it holds true
Underside "feel"
yellow, better defined
reddish, markings blended or smudged
together.
Subjective test but may help when other
features considered