The chrysalis, which is figured on Plate [116] (after Frohawk), is ochreous when first formed, but becomes darker gradually; the wing-cases, however, remain of the original colour, but their hind margins darken. From a chrysalis found on July 12 the butterfly emerged on July 16.
There is some evidence in favour of the supposition that this caterpillar is in some way dependent upon ants for nourishment after the third moult, if not before, but what the exact requirement may be is not known. Probably the circumstances connected with the discovery of the chrysalis in 1905 by Messrs. Frohawk & Rayward may afford a valuable clue to the direction in which their future investigation will have to be conducted. We may hope, therefore, that the mystery that has so long hung over the last stages of the caterpillar will be solved before very long.
Lewin (1795) and Donovan (1796) both refer to this as a rare English butterfly. The former states that it is on the wing in July, and is found on high chalky lands in different parts of the kingdom, having been taken on the cliffs in the neighbourhood of Dover, Marlborough Downs, the hills near Bath, and near Clifden in Bucks.
Stephens, in 1828, wrote of it as "an insect of great rarity." He mentioned the localities given by the older authors, and added that it had been taken in the Mouse's Pasture, near Bedford, in rocky situations in North Wales, and had been plentiful near Winchester.
Newman (1871) wrote, "Its 'metropolis,' if I may borrow an expression from the revered fathers of British entomology, is in South Devon; it has occurred in some abundance in Somersetshire, and on the Cotswold Hills in Gloucestershire; from Gloucestershire we ascend to a Midland county, Northamptonshire, in which county (at Barnwell Wold) a considerable number have been taken." One specimen was reported from Charmouth in Dorsetshire, and the butterfly has also been recorded from Herefordshire, but these are matters of ancient history. At the present time the species is only to be found in limited numbers in the Cotswolds; it seems to have become much rarer than formerly in its South Devon locality, i.e. Bolthead, near Plymouth; one never hears of it now from Clovelly, in North Devon, where, according to Dale, it was once reported to be abundant. In 1891 Messrs. Waterhouse obtained a fine series of specimens in West Cornwall, and since that time the district has been annually visited by an increasing number of entomologists. Judging from the "big bags" that are made each year it would seem that the butterfly has a very strong and widely distributed settlement in those parts.
Abroad it is distributed throughout Europe, except the Polar and the south-western parts, and is also found in Armenia, Bithynia, and South Siberia.
Our next species belongs to the Nemeobiinæ, a sub-family of Lemoniidæ = Erycinidæ. Only one member of the family is known to occur in Europe; this is Nemeobius lucina.
As the fore legs of the male butterfly are aborted, and are therefore useless for walking, the species would seem to come near the Nymphalidæ, in which the fore legs of the butterflies, in both sexes, are reduced. In its early stages, however, the species seems to be most nearly related to the Lycænidæ.