Wing span: 26–34 mm
Flight period of butterflies: in one generation from July to October
Larval host plants: common restharrow (Hippocrepis comosa)
The Karst blue (Polyommatus coridon or Lysandra coridon or Meleageria coridon) belongs among the larger blues, but it is still a fairly small butterfly. The male is dorsally deep blue with a pronounced metallic sheen, along the edge of the forewings he has a broad black-gray band; this is narrow on the hindwings, but here it is joined by a series of oval black-gray spots. The dark color of the marginal band, following the veins, extends into the interior of the wings. The underside of the male is light to brownish-gray with a light turquoise sheen near the body and a pattern of black spots with a broad white border in the middle of the wings. The orange-black 'eye-spots' lined along the outer edge of the underside of the hindwings are white-edged. For the Karst blue there is also an elongated white patch between the band of orange and a row of white-edged black spots on the underside of the hindwings.
The female is dorsally dark brown and has along the lower edge of the hindwings a series of orange eye-spots. As with the male, the fringes on the edge of her wings are bicolored, white and gray-brown, but the two-tone of the female's fringes is even more pronounced. The underside of her wings is brown with a greenish sheen near the body, the pattern of black spots with a broad white border and orange eye-spots is the same in the female as in the male.
The Karst blue is also a myrmecophilous ('ant-loving') species, as some species of ants adopt growing butterfly larvae and then take care of them until the caterpillars pupate.
The Karst blue is a common warm-loving species in our country. It lives on colorfully flowering dry meadows and shrub-covered areas with low grass, for example on Karst meadows. It prefers warm habitats on calcareous substrates, where it occurs from the lowlands to high mountains.
