It is found in chalk downland, in warm, sheltered spots, flying low over vegetation, seeking females that are rich chocolate brown in color.

The male has the upper side wings a brilliant sky blue, with a fine black line round the edge and a white margin.

Of the size of icarus but the male above of a very light and glittering sky-blue: the female dark brown, with a red submarginal band and on the forewing a black discocellular spot.

The underside bears some resemblance to that of coridon, as the rings of the ocelli are large and contrast conspicuously with the brown ground, which is especially dark in the female.

(81 c) [Lysandra × polonus (Zeller, 1845)] is found only in certain districts East Prussia, Russia, Syria and Spain; the light blue colour is shaded with silvery, the black border is somewhat broader and the hindwing bears dark dots at the outer margin.

latefasciata Schultz — In Algeria flies a form which has a magnificent glossy blue upperside, is usually somewhat larger than Central European specimens and has distinct black spots before the distal margin of the hindwing above; this is punctifera Oberth.

Also in Europe occur occasionally specimens with traces of some submarginal dots on the hindwing above, without the other characters of punctifera; Aigner-Abafi named this form ab.

German entomologist S. A. von Rottemburg described the Adonis blue in 1775 as Papilio bellargus, noting it was very rare locally but came to his garden in June.

Sometimes human-created landforms provide refuges for the plant and the butterfly; an example of this is on Martin Down in Dorset, where horseshoe vetch only occurs on ancient earthworks with thin calcareous soils.

[4] The Adonis blue is at the most northerly edge of its range in Britain and has always been restricted to the warmer dry calcareous grasslands of southern England.

There are efforts from conservation organisations and local Biodiversity Action Plans to encourage the populations of chalk-grassland butterflies through managed grazing programs.

The recent hot and dry weather associated with climate change seems to be beneficial for this species by making more habitats suitable.