Malopolskie, Poland Lasiommata petropolitana, the northern wall brown, is a butterfly species belonging to the family Nymphalidae.

[1] It can be found in large parts of Europe, from the Pyrenees and Alps up to Scandinavia and Finland, east to Russia and Siberia.

Above very similar to the next species, maera, but always black-brown, of the colour of the darkest maera form, the forewing less pointed, with straighter distal margin; on the underside of the forewing the russet-yellow distal band does not extend without interruption to the anal angle, but stops at the lower median vein or is there interrupted.

The apical ocellus, moreover, has less often a double pupil, being mostly quite circular and not always accompanied by a small accessory eye-dot (towards the apex), as is nearly always the case in maera.

— Larva uniformly green, the dark dorsal line being only distinct posteriorly; on Festuca.