Brown Argus - Aricia agestis. This butterfly is found in most parts of central and southern Europe but is absent from Spain , Portugal and Fennoscandia. In the British Isles it is widespread in the southern half of England and Wales but is replaced by the Northern Brown Argus in Northern England and Scotland . The usual habitats are chalk downlands and sandy heaths. The caterpillar has a black head and the body is green with purplish lines along the back and sides. It feeds on the foliage of rock rose (Helianthemum), stork's bill (Erodium) and cranesbill (Geranium). Caterpillars of the latter brood overwinter and pupate at the base of the food plant in the following spring. Butterflies may be found between April and August, according to locality. Usually double-brooded but in southern Europe there are three generations a year.
Text: Butterflies and Moths in Britain and Europe
(1982) David Carter. Pan Books
