The Adonis Blue (Lycæna bellargus).
The butterfly on Plate [110] is the Clifden Blue of Moses Harris (1775), so named because it was said to have been first observed at Clifden in Bucks. The male is of a beautiful bright blue colour, but as in the same sex of the previous two species, it is not quite constant in tint. In some specimens we find a distinct mauve shade, and in others, but more rarely, the blue colour is tinged with greenish (Plate [118,] Fig. [11]): the veins become distinctly black on the outer margins, and appear to run through the white fringes on all the wings. Often there are black dots on the outer margin of the hind wings. The female is dark brown, sometimes slaty-black, with orange spots or crescents on the outer margins; these are often only faintly in evidence on the fore wings, and sometimes this is the case on the hind wings also; there is a black discal spot on the fore wings, and the fringes of all the wings are white chequered with black. The bases of the wings are powdered with blue, but this is more noticeable on the hind wings. On the under side the fore wings of the male are greyish, and the hind wings greyish-brown; all the wings of the female are brownish, with a faint grey tinge in some specimens; the ornamentation is very similar to that of the Common Blue. The two figures on Plate [110,] showing specimens with the wings closed, represent typical male and female, and the other figures of under sides on this plate exhibit minor aberrations from typical lines; examples of the more extreme variations will be found on Plate [118,] where also are figured some uncommon aberrations in the colour of the male on the upper side.
There is often a tendency in the female to assume the colour of the male, and this is usually seen on the hind wings, but occasionally on the fore wings also. In the extreme form of this phase of variation, var. ceronus, the whole of the upper surface, with the exception of the orange-spotted borders, is almost as blue as that of the male. This is a parallel aberration to that of the Chalk Hill Blue known as syngrapha, but it seems to be somewhat rarer in this country.
Figures of the early stages will be found on Plate [111.]
The egg is greenish-white, becoming rather greener in tint towards the top, which is depressed; the netting is whitish and shining, and somewhat rougher on the sides than towards and on the top.
Buckler describes the full-grown caterpillar as deep, full green in colour, covered with tiny black speckles, bearing little black bristles, which are longest on the dorsal humps and on the yellow-edged ridge above the spiracles; on the top of each of the eight pairs of dorsal humps is a deep bright yellow longitudinal dash, somewhat wider behind than in front; these dashes form in effect two yellow stripes interrupted by the deeply sunk segmental divisions; the line along the back is darker than the ground colour, and the spiracles are black. The head is dark brown, and there are two yellow dots on the first ring of the body near the head.
The chrysalis, when first formed, is greenish-brown with the wing-cases greenish, the whole afterwards becomes ochreous; the thorax and wing-cases are rather glossy, and the body is slightly hairy. Buckler states that some of his caterpillars buried themselves about half an inch deep in the loose soil, and formed a weak sort of cocoon; others, not having been supplied with soil that could be so easily penetrated, retired under the stems of their food-plants, and in angles formed by the branching stems spun a few weak threads to keep themselves in place.
The food-plant is the horseshoe vetch (Hippocrepis comosa). From eggs laid in August, the caterpillars appear to hatch towards the end of September, but do not feed up until the spring. Butterflies from these caterpillars are on the wing between the middle of May and the middle of June, thus occupying about nine months in passing through the various stages from egg to perfect insect. From eggs laid in May and June the butterflies appear in August and September. Although it is found in similar kinds of situations to those affected by the last species, and sometimes on the same grounds, it is more local, and almost confined to the counties of Kent, Surrey, and Sussex. It is, however, rather common at Ventnor and in some other parts of the Isle of Wight, and is found near Winchester. Barrett states that it is abundant at Corfe Castle, Dorset, and gives as localities for the butterfly Wotton-under-Edge, and near Bristol, near Torquay, Sidmouth, and Seaton. Its range abroad extends through Central and Southern Europe, to Armenia, Northern Asia Minor, and Western Kurdistan. It is also found in North-West Africa, where the males are greenish-blue with conspicuous black spots on the outer margins of the hind wings; this is the var. punctifera.