Pl. 55.
Dark Green Fritillary.
Eggs, natural size and enlarged; caterpillar and chrysalis.
Moorlands, downs, sea-cliffs, and flowery slopes are the kind of situations most to the fancy of this agile butterfly. It is on the wing in July and August, and is much more easily seen than caught. However, it is rather fond of perching on the taller kinds of thistles, and is then not difficult to capture, if quietly approached. It is common locally in most of the English and Welsh counties. In Ireland it seems to be chiefly attached to the coast, and is plentiful in some of its localities. In Scotland it occurs in many suitable districts, but Skye is the only one of the isles from which it has been reported. Its distribution extends through Europe and Asia to Amurland, China, and Japan.
The Queen of Spain Fritillary (Argynnis lathonia).
In shape and in general appearance this butterfly is not unlike a small example of the Silver-washed Fritillary; the large silvery, or sometimes pearly, blotches on the under side of the hind wings at once reveal its higher British rank. When flying it has a curious resemblance to the Wall, and sometimes it has been taken when the captor supposed that he was netting a specimen of that plebeian butterfly. The black markings on the upper side vary somewhat in size, and occasionally those on the front area, or those on the inner area of the fore wings, are more or less confluent; very rarely the wings are suffused with a steely-blue or bronze colour. The specimens occurring in this country do not, however, exhibit so much variation as has been observed in this butterfly abroad.
I have not seen any of the early stages. The figures of the caterpillar and the chrysalis (Plate [58]) are after Hübner, and the following descriptions of the egg and other stages are adapted from the detailed life-history of the species by Mr. Frohawk, published in the Entomologist for 1903:—
"The egg is one-fortieth of an inch high, of a rather straight-sided conical form, widest at the base, where it is smooth and rounded off at the edge. There are about forty longitudinal keels, irregularly formed and of different lengths, some not reaching halfway up the side, and others running the entire length from base to crown, where they terminate abruptly, and form a series of triangular peaks round the summit surrounding the granulated micropyle; the spaces between the keels are finely ribbed transversely. When first laid it is of a very pale lemon-yellow colour, inclining to ochreous, appearing almost white in certain lights; the colour gradually deepens, becoming yellower with a greenish tinge. On the fifth day the crown of the egg assumes a dull grey, finally changing to a lilac-grey."
The female butterfly, when placed in the sunshine, laid about a hundred eggs during the day—August 7. These were mostly placed singly on the leaves or other parts of a plant of heart's-ease (Viola tricolor), but some were laid on the gauze cover of the cage. All the caterpillars hatched out on August 14.