Identifying features
Medium to large butterfly with a wingspan of 45–64 mm and large, broad wings. The wings’ base colour is brownish-yellow with black spots. The outer edge is scalloped, with light tufts both from the outside and inside, a dark edge, and a border of blue, crescent-shaped spots. At the front edge of the forewing, there are two large, black, square spots, and in the middle of the wing, three round, black spots. The underside of the wings is mottled brown. The larva is black with long, branched, yellow thorns.
Similar species
It can be very easily confused with Comma. Often, the only visible difference on the upperside is that large tortoiseshell has a blue or bluish-tinged wing margin at the outer edge of the wing, while Comma has a similar yellow or yellowish-brown margin. It also appears almost like a larger and paler version of Small Tortoiseshell (Aglais urticae).
Distribution
There are several older finds, mainly from Southern Norway, but it is unclear whether the species ever formed permanent populations in Norway. It is unlikely to be found in the country today.
Biology
The larvae live in an unusual way on maple trees, especially elm, but also among other cherry and apple trees. The adults often come to sap that flows from wounds in the trees or from stumps of newly felled trees.