The chrysalis, of which two figures are given, had a pale brownish and rather shining head; the body was brown with a darker line on the back; the thorax and wing-cases dull yellowish-green, the former rather glossy. It was placed in an angle formed by a side and the floor of the cage, lying quite flat and secured by silken threads, which, owing to position, I was unable to examine. Some of the caterpillars that Mr. Frohawk reared were pale green with a dark purplish stripe on the back. Another food-plant is bird's-foot vetch (Ornithopus perpusillus).
The butterfly is on the wing in July and August, and seems to be more often found on sandy heaths than elsewhere. It is especially common, in some years, in the heather-clad districts of Surrey and Hampshire, as well as other counties in England. In Norfolk and Suffolk it is said to be common, but scarce in Gloucestershire and Somersetshire. Its range extends through the greater part of England and Wales, and into Scotland as far as Perthshire. Specimens from the northwest coast of Wales are said to be larger than those from inland localities.
As regards Ireland, there is only Birchall's record, "The Murrough of Wicklow, and near Rostrevor," in evidence of the butterfly occurring in that country at all.
Abroad, it appears to range pretty well over the whole of Europe, and through Asia eastward to Siberia, Corea, and Japan.
The Brown Argus (Lycæna astrarche).
Fore wings blackish or sooty-brown with a black discal spot, and a row of reddish-orange spots on the outer margin of all the wings; the fringes are white, sometimes with blackish interruptions. The under side is greyish or greyish-brown, and the black spots are distinctly ringed with white. On the fore wing there are seven of these spots, one at the end of the cell, and the others in an irregular series beyond; the last in this series is sometimes double, or it may be absent. On the hind wings the spots comprise a series of four preceding the white discal mark, and a series of seven beyond; the second spot in this series is placed directly under the first, forming a colon-like mark, and this character will help to distinguish the Brown Argus from the blackish or brown females of the next species.
The female has larger orange markings, and the outline of the fore wings is rather rounder on the outer margin, otherwise the sexes are very similar.
The orange spots referred to in the male are sometimes absent towards the tips of the fore wings, and in this respect lead up to the form known as the Durham Argus (var. salmacis, Stephens), which is blackish above and ochreous-brown below; the black spots on the under side are much smaller then in typical specimens, and some may be absent altogether. The male has a black discal spot, and the female a white one, on the upper side of the fore wings; the hind wings have a red or orange band on both surfaces. Sometimes the male also has a white spot on the fore wings. Specimens with the orange spots on upper side almost entirely absent are referable to var. allous.
Artaxerxes is the form occurring in Scotland, and is known as the "Scotch White Spot." Both sexes have a conspicuous white discal spot on the fore wings, and the spots on the under side are white, and rarely centred with black. In var. quadripuncta, Tutt, all four wings have a white discal spot above. Occasionally an odd specimen with white discal spots is found in the south.