- Family: Brushfooted Butterflies (Four-footed Butterflies) – Nymphalidae
- Subfamily: Heliconians (Longwings) – Heliconiinae
- Wing span: Medium-sized, 35–45 mm (1.37–1.76 in.). Females larger than males.
- Wing upper side: Orange with black blotches.
- Wing underside: Forewing orange with black blotches and spots. Black, very meandering stripe with white inner edge divides hind wing in two. Inner part a colourful rust-red and white area with white-edged, arrow-shaped black arcs. Reddish brown strip immediately on outer side of dividing strip. Edge of wing with row of white blotches, basal edge with reddish brown triangles. Lighter area between margin blotches and stripe, with row of dark, unclear spots. Row of white blotches between dark spots on basal side of wing.
- Habitat: Fell heaths above tree-line.
- Flying time: Latue June–early July.
- Overwintering form: Caterpillar (overwinters as a caterpillar apparently 2 seasons).
- Larval foodplant: Unknown. Probably mountain avens (Dryas octopetala) and Arctic white heather (Cassiope tetragona).
- Endangerment: Endangered.
The Polar fritillary can only be found in Finland on the high fells of northern Lapland. Good identifying marks are: 1) the margin blotches on the upper side of the hind wings, which form a black arch with the orange blotches, 2) the black meandering stripe on the underside of the hind wings which has a white inner edge, and 3) the white T-shaped margin blotches which have unclear dark triangles on their inner sides.
The males fly around the high fell tundra looking for females. There is no information available on how they lay their eggs.