The caterpillar is green, striped on the back and sides with yellow. A decidedly southern species, frequenting the chalk downs of the South and the Isle of Wight, or the limestone districts of the Midlands. It is out in July and August.
The Azure Blue or Holly Blue (Lycæna Argiolus), [Plate XIII.], Fig. 4.—This is a very dainty little butterfly of a deep sky-blue, with rounded wings narrowly fringed with white, ticked with black. The female has a broad, irregular, black border, occasionally extending well into the wing. But the under side ([Plate XV.], Fig. 3) marks a new departure, being of a very pale, shimmering blue, with only a few small, black spots, which form an incomplete row on fore- and hind-wings.
PLATE 15
1. [Brown Argus] (var. Artaxerxes)
2. [Brown Argus] (var. Artaxerxes) (under side)
3. [Azure Blue] (under side)
4. [Silver-Studded Blue] (under side)
5. [Common Blue] (under side)
6. [Brown Argus] (under side)
7. [Mazarine Blue] (upper side)
8. [Mazarine Blue] (under side)
9. [Chalkhill Blue] (under side)
10. [Large Blue] (under side)
11. [Little Blue] (under side)
The caterpillar is green, with a dark line on the back, and a black head. It feeds on the flowers of Holly, Ivy, and Buckthorn.
Being double-brooded, the perfect insect appears first in April and May, and again in August. It is generally distributed in England, though commonest in the South; not known to occur in Scotland.
The Mazarine Blue (Lycæna semiargus), [Plate XV.], Figs. 7 and 8.—Males, a very dark purple-blue—in fact, this is our darkest “Blue,” and shares the distinction with the Long-Tailed Blue of being extremely scarce. Possibly those met with now are visitors from the Continent. The blue deepens into a black border at the margins; fringe short and white. Female, a uniform dark brown; under side a pale buff colour, with an irregular row of black spots edged with white. There are no orange spots on this species. It is said to feed on Thrift; hence it is likeliest to be met with near the coast during July. Good Continental specimens can be purchased cheaply, or got by exchange. And I hold it is better to fill in your row with these, carefully labelling them to indicate their source, than to have an empty space always staring you in the face. Unless this species becomes more common, the average collector’s chance of capturing British specimens is exceedingly remote.
The Little Blue (Lycæna Minima), [Plate XIII.], Fig. 3.—The smallest of our butterflies, the average expanse being only 3/4 inch. Male, blackish-brown dusted with blue towards the base of the wings. Female, solid brown; under side ([Plate XV.], Fig. 11) a pale salmon, blue spotted as in Argiolus, with black outlined with white; no orange spots on either sex.