- Family: Brushfooted Butterflies – Nymphalidae
- Subfamily: True Brushfoots – Nymphalinae
- Wing span: Large, 53–69 mm (2.12–2.76 in.).
- Wing upper side: Orange, leading edge of forewing with a row of black and white or pale yellow blotches. Black blotches also in middle of forewing and leading edge of hind wing. Especially margin of hind wing with row of black-edged blue arcs. Forewing margin black.
- Wing underside: Marble pattern composed of different shades of brown. Base of wing darker than outer part. Margin of both wings with thin shiny dark blue strand.
- Habitat: Open forests and fruit trees in gardens.
- Flying time: Initially from May–mid-June, then mid-July–mid-August.
- Overwintering form: Adult butterfly.
- Larval foodplant: Aspen (Populus tremula), elms (Ulmus), willows (Salix) and fruit trees, e.g. apple (Malus domestica).
The large tortoiseshell is very rare in Finland. It usually arrives from the south-east and can temporarily overwinter in the country.
The large tortoiseshell can be differentiated from the small tortoiseshell besides by the size by the more orangey colour of the upper surface of its wings and the orange base of its hind wings. It differs from the compton tortoiseshell in that it is lacking a white blotch on the leading edge of its hind wings. Compared to the yellow-legged tortoiseshell it has yellower blotches on the leading edges of its forewings and the dark margin band is thinner. The surest way to recognize it, however, is by its dark feet (hairs): yellow-legged tortoiseshell’s feet are light-coloured.
Males wait for females in forest clearings and margins, where they defend their territory. The females lay their eggs in clusters in the branches of the host plant. The caterpillars colonise the host plant together. No caterpillars have been found in Finland.