Figures of the butterfly will be found on Plate [105,] and of its life history on Plate [104;] the upper egg is that from a typical female, and the lower one was laid by a female artaxerxes.
The egg, which is whitish, with a faint greyish tinge, is laid on the upper side of a young leaf of the rock-rose (Helianthemum chamæcistus). The caterpillar has a black shining head; the body is green with whitish hairs, a pinkish line along the back, a whitish one bordered with pinkish along the sides; the green colour becomes dingy as the caterpillar matures. The chrysalis is obscure yellowish-green, the front of the thorax is edged with pinkish, and there are bands of the same colour on the back and sides of the body; the thorax and the wing-cases are rather glossy. Held in position by a few silken threads between leaves of the food-plant.
The ordinary form of the butterfly is on the wing in May and June, and again in August. It is widely distributed throughout the southern half of England, and also in Wales.
Although chiefly associated with rock-rose, especially in chalky districts, it occurs too among stork's-bill (Erodium cicutarium), upon which plant the caterpillar also feeds, in sandy places inland as well as on the coast.
Caterpillars from the first flight of butterflies may be found in July, and those from the second flight hibernate and feed up in April.
The butterfly has a marked liking for roosting on the flower stems of long grasses, and quite a number may often be found resting together towards sundown, or on dull days, in sheltered hollows. Sometimes several specimens of this species and of the Common Blue may be found on the same perch. It is rather less frequently seen in the Midland counties, but it is more or less common in some parts of Derbyshire, Yorkshire, and Lancashire.
Larger Image
Pl. 106.