Blemish (lepidopterology)

A blemish ( Latin macula , 'spot') in butterfly studies ( lepidopterology ) is a spot on a butterfly's wing that can be helpful for determining the species, especially in owl butterflies . Depending on the position on the wing, one differentiates:

Ring flaw: A mostly round, occasionally elongated flaw in the central cell of the forewing. It can be open towards the front edge or reduced to a small point.
Kidney Flaw : A mostly elongated, often kidney-shaped flaw at the end of the middle cell of the fore wing. It can be colored similar to the ring flaws or it can be the dominant drawing element.
Tenon flaw: A mostly elongated flaw that protrudes from the inner transverse line into the middle field. It can be reduced to a dark point at its tip or connected to the outer transverse line by a black line.

Examples

Perigrapha i-cinctum : The large, bright, outer, kidney-shaped spot on the forewings is the kidney flaw. The light spot in the center cell, which shows the shape of an 8, is the ring flaw. A tenon flaw of this type is missing.
Ulochlaena hirta : The yellow-brown, kidney-shaped spot is the kidney blemish. The yellow-brown, teardrop-shaped spot is the ring flaw. The yellow-brown, elongated mark below the ring flaw is the cone flaw.
Mountain steppe earth owl ( Euxoa recussa ): The light brown, kidney-shaped spot is the kidney flaw. The light brown, almost circular spot is the ring flaw. The black, elongated mark below the ring flaw is the tenon flaw.
Exclamation mark ( Agrotis exclamationis ): The large, kidney-shaped, dark brown-edged spot open towards the front edge is the kidney defect. The circular, dark brown-edged spot, open towards the front edge, is the ring flaw. The black, elongated mark below the ring flaw is the tenon flaw.