The egg is at first greenish, then yellowish, and afterwards greyish, and then becoming blackish towards the hollowed top. The ribs seem to be eighteen or twenty in number; laid in June or July on plants of dog-violet. On emerging from the egg the young caterpillar devours most of the shell. It is then of a pale olive colour with brownish warts, from each of which there is a pale and rather long jointed bristle; the head is black. The full-grown caterpillar is smoky pink and velvety-looking. There is a brownish line along the middle of the back. The spines are "ochreous in colour, tinged with pink, and beset with fine pointed black bristles." The upper ones are rather stouter than the others, and the pair on the first ring, the only spines on this ring, are rather more than twice the length of the others, and are directed forward over the head, thus giving the appearance of a pair of horns; the second and third rings have each four spines, which are rather finer than those on the rest of the body, which are arranged in six rows. A pale pinkish stripe runs along the lower part of the body; just above the feet. Head black and notched on the crown (Buckler). The chrysalis is brown on the thorax and the body; the wing-cases are more ochreous and marked with black near the edge. There is a black V-mark on the thorax, with a silvery spot on each side, one silvery spot on each side of the head, and other metallic spots on the body near the thorax (Buckler).
On the Continent there are two broods of the butterfly, and specimens are occasionally seen in August in this country; one of these late examples, taken by Mr. Barker in 1881, is shown on the plate (Fig. [6]). Sometimes one or two caterpillars of a brood in confinement will feed up and attain the perfect state in August instead of settling down with their companions for hibernation.
The butterfly in June and July frequents similar places to those favoured by the Pearl-bordered, and its distribution in Britain is somewhat similar, although it is a more local species. It seems, however, to be commoner in Scotland than the Pearl-bordered, and has been recorded at least once from Ireland.
Its range abroad extends farther east, as it is found in Corea.
The Heath Fritillary (Melitæa athalia).
The ground colour of this butterfly, sometimes called the "Pearl-bordered Likeness" or "May Fritillary," is brownish-orange, and the markings are black or blackish; the bases of the wings are clouded with blackish, and the fringes are white checkered with black.
The ground colour varies in tint, and may be pale tawny or deep reddish. The black markings are subject to modification in two directions; in one leading up to almost complete disappearance from the central area, and in the other they are much intensified and greatly obscure the ground colour. Sometimes the whole of the wings, with the exception of a series of orange spots on the outer area, are blackish. This form is known as var. navarina. The left-hand figure at the bottom of Plate [68] shows an aberration approaching this form, whilst the right-hand figure comes close to var. corythalia. Specimens with all the wings thinly marked with black, as in the fore wing of the variety last referred to, would be referable to var. obsoleta.
According to Barrett, specimens from Essex have the ground colour on the under side of the hind wing much yellower than are the same parts in specimens from Sussex. I have not noticed this, but some Essex examples that I have seen were much darker and more heavily marked with black on the upper side, and especially on the hind wings, than any that I have seen from other parts of England, except, perhaps, a few individuals from North Devonshire. These Essex specimens reminded me very much of M. dictynna, a Continental species, with which, it appears, the Heath Fritillary was confounded by some of the old authors.
