[4] The Latin species name boeticus refers to Baetica, a province of the Roman Empire in the Iberian Peninsula .

Its common name refers to the long streamers on its hind wings, the male's bright iridescent blue colour, and peas, which is the typical host plant of the butterfly.

[6] This species inhabits the edge of forests, mountain meadows and hot flowery places at an elevation up to 2,700 metres (8,900 ft) above sea level.

[8] In these small butterflies (although unusually large for their family) the males have a mainly blue violet upper face of the wings with the brown edges, while the females have only a small amount of blue colour in the centre of the wings (sexual dimorphism).

[9] The underface of each hindwing shows a pair of small black eye-spots beside each tail, with an orange marginal spots at the anal angle.

Upperside violet-blue, with hair-like, whitish scales dispersed over the entire surface of both wings.

Upperside with some slight brownish suffusion, some shining blue scales at the base of both wings and in the interior portion of the forewing; on the hindwing there are two spots in interspaces 1 and 2 as in the male, and some pale brown spots in continuation up the wing, all outwardly edged by a fine white subterminal line, and across the disc there is a narrow white band, divided by the veins.