About Erebia montanus von Prunner, 1798
Erebia montanus (originally mislabeled as Erebia montana here) has a wingspan of 44–50 millimetres (1.7–2.0 in). These are small dark brown butterflies that have a broad bright orange postdiscal band. This band holds two oval white-pupiled markings at the apex of the forewings, plus one or two other less visible markings, and a series of three or four ocelli on the upperside of the hindwings. The underside of the forewings is red brown, with two ocelli at the apex and a wavy edge. The underside of the hindwings is marbled chestnut brown, which is the origin of its common name, with clearly marked whitish veins.
Seitz's description of this species, referred to there as E. goante Esp (= scaea Hbn.) (37 c): The upperside markings match those of Erebia nerine, but the ocelli are usually somewhat smaller, and the female's hindwing is more distinctly dentate. The forewing band narrows toward the posterior; it is bright russet in males and light russet-yellow in females. Two connected black ocelli with white centers lie near the forewing apex, and a black ocelliform dot sometimes appears above them, which only rarely has a pupil. A further small ocellus, occasionally with a white center, is present toward the hindmargin. In the somewhat narrower distal band of the hindwing, there are 3, rarely 4, black white-centred ocelli. The underside of the forewing is russet-brown, lighter in females, with a black-brown margin, and the apex is dusted with white-grey. The underside of the hindwing is black-brown, marbled with white-grey. The strongly dentate central band is bordered externally by a band-like line formed from accumulated white scales, which is interrupted in places; 3-4 black white-centred eye-dots are present toward the distal margin. Females are lighter in overall colour, with larger ocelli. The female's hindwing underside is white-grey, thinly dusted with brown flecks, and the veins have sparse white scaling. The male's distal margin is somewhat lighter than the ground colour, while the female's distal margin is chequered brown and white. This population occurs in the Alps in the mountain and subalpine region, as well as in the High Tatra and the Carpathian Mountains; a small form occurs in the Western Pyrenees, which Herrich-Schaeffer figured as gorgone, which is not considered part of the current understood distribution and may be a misidentification.
The adult butterfly flies in July and August, in dry stony localities, and prefers to settle with its wings half open on rocks. This species is rather similar to Erebia stirius, Erebia styx and Erebia pronoe. Regarding distribution and habitat: this species is found in Austria, France, Italy, Liechtenstein and Switzerland. These high-mountain butterflies inhabit warm rocky slopes, woodland clearings, and flower-rich grasslands. In the Alps, they occur from the Ligurian Alps and French Alps to the Tyrol and Dolomites, and they are also found in the Apuan Alps, as well as northern and middle Apennines, at elevations between 1,100 and 2,500 metres (3,600–8,200 ft) above sea level.
