In Ægon, the male is a warm violet-blue, the outer margins being bordered with black. The female is brown shot with blue, which becomes more intense near the outer margin of the hind-wings, where there is a row of orange spots touching an outer row of black spots; but these two rows may be nearly or altogether absent. The under side ([Plate XV.], Fig. 4) is banded with orange and black-spotted, the black spots being ringed with white. The silver studs are on the outer margin of the orange band, principally on the hind-wings. This is a fairly abundant species all over England on dry soils, and has been met with in Scotland. The caterpillar is green, sometimes brown, with a darker line along the back and white lines on the sides. It feeds on Clover, Vetch, Broom, and other leguminous plants. The butterfly is out in July and August.
The Brown Argus (Lycæna Astrarche), [Plate XII.], Fig. 11. —Here is a “blue” in which both sexes are brown, a rather unusual thing. In every other particular, however, it bears the family hall-mark. The upper surface is dark brown, bordered with bright orange spots. The under side ([Plate XV.], Fig. 6) is banded with orange and spotted with black dots ringed with white. For the Scotch variety, Artaxerxes, these spots are solid white, and there is in addition a white discoidal spot on the upper side of the fore-wing. This variety is local in Scotland, but fairly numerous where found, generally near the sea, and plentiful all along the Ayrshire coast in June and July. It is said to feed on Helianthemum, but has probably many other food-plants, such as the Hemlock Stork’s-bill (Erodium cicutarium), which is common where it flies.
The caterpillar is green, with a darker line along the back, and a pale line on each side; head black and shining. There are many intermediate forms between Artaxerxes and the type.
The Common Blue (Lycæna Icarus), [Plate XII.], Fig. 12.—Known to everyone who sees anything at all of the country. It is the blue butterfly, noticed even by those who hardly know a butterfly from a bullfrog.
An intelligent little chap he is, too, with an eye for his own safety, as I once found when I had the opportunity of observing quite a number of them on a piece of waste ground near the sea. The weather was dull and threatening rain, and not a butterfly was on the wing; but I could see plenty of our common blue friend hanging on, with closed wings, to the ends of rushes, grass-stalks, and on thistle-tops; but always when I came within a step or two they adroitly changed their position, putting whatever they were resting or hanging on between us, just edging round the corner as it were, so as to be out of sight. Apparently the idea of flying away from an enemy was here considered as too risky under the conditions which prevailed; the safest plan was to hide, so hide they did. It was the funniest game of hide-and-seek I ever played. I have since seen the small blue dragon-flies adopt the same tactics on the rushes by the side of a pond. No wonder this little fellow is so common. In the struggle for existence he has shown himself able and well-fitted to survive; nevertheless I had a good time amongst them that afternoon and boxed some fine varieties. The male bears a warm shade of blue, and the female is from nearly black to brown, with a blue blush spreading from the body outwards, both wings being bordered with a row of orange and black spots, often on a ground of white. Sometimes, too, there is a discoidal black spot edged with white; but the females are very variable. The under side ([Plate XV.], Fig. 5) has the characteristic markings of the “blues,” and, excepting that the female is a little darker in ground colour, both sexes are pretty much alike.
The caterpillar is green, with a dark line on the back, and a light yellow line on each side; it feeds on Trefoil and Clover. The perfect insect is common everywhere from June till August.
[The Clifden Blue, or Adonis Blue (Lycæna Bellargus)], [Plate XIII.], Fig. 1.—It will be sufficient to point out the specific characters of each of these blues without going into minute detail, which would be wearisome, even if it were possible (which it is not) to paint in words what Nature has painted so admirably on the butterflies’ wings. The male Adonis is a brilliant azure blue; fringe, deep and white, and divided into sections by black lines. Female, brown to nearly black, with a row of orange and black spots round the base of the hind-wing and sometimes continued faintly into the fore-wing; it is browner on the under side than the male. Both resemble the Common Blue very much, but the spots are scarcely so numerous or so bold. The wings, however, are generally more ample, those of the males being more rounded.
The caterpillar is green, with a darker line on the back, and a yellow line on each side; spotted with orange on the back. This is a fairly common species confined mostly to the South, where, being double-brooded, it is out in June and August.
The Chalk-Hill Blue (Lycæna Corydon), [Plate XIII.], Fig. 2. —A larger insect than the last, and the male an extremely pale iridescent blue, which is shaded off at the margins into a black border, with a white fringe checked with black. Female, dark brown, black and white checked fringe; eye-spots nearly obsolete along the margin of both wings. Under side in male almost white, shading to pale green, blue next the body on the fore-wing; hind-wing, with a wash of pale brown for the ground; spots black, outlined with white. A marginal row of orange spots is confined to the hind-wing in the male, but extends to the fore-wing in the female; the ground colour of it, however, is a pale fawn, which sets forth the eye-spots beautifully.