Pl. 71.
Glanville Fritillary.
1, 2, 4 male; 3, 5, 6, 7 female.
The Milkweeds (Asclepias) are not indigenous plants, but, as pointed out by the late Mr. J. Jenner Weir, A. purpurescens and A. tuberosa are hardy in this country. He endeavoured to ascertain whether these plants, or either of them, were grown in any of the gardens in the Cornish locality where four fresh specimens were captured in September, 1885. I do not find that the desired information was furnished. Recently I have ascertained that A. cornuti, which grows to a height of four feet, is used as a border plant in some parts of England. It is commonly known as Swallow-wort, and is esteemed for its fragrant pale purple flowers.
We now come to the Satyrinæ, which, as regards the number of species belonging to it, is a very large sub-family. In Great Britain, however, there are but eleven species, and although some of these are rather local, none are really scarce, and most are common.
The Marbled White (Melanargia galatea).
Older English names for the butterfly figured on Plate [75] are "Our Half-mourner" (Petiver, 1717), "The Marmoris" (Wilkes), and "The Marmoress" (Harris). The ground colour is white or creamy white, and the markings are black. On the under side the markings are similar in design to those on the upper side, but much fainter: the eye spots, which are not always in evidence above, are well defined below, and especially so on the hind wings. The female is generally whiter and larger than the male, and has the basal half of the costa, or front margin of the fore wing ochreous brown, and the markings on the under side of the hind wings are tinged with the same colour.
Variation consists chiefly of increase or decrease in the size of the black markings. At least one specimen is known in which all the wings are uniform smoky black. This is in the collection of Mr. A.B. Farn, and was captured near Rochester, Kent, in 1871. Between this extreme and specimens with the black markings of typical proportions there are various modifications; but striking aberrations are rare in this country. Sometimes there is entire or partial absence of black pigment. A remarkable example of this kind of aberration, taken on the cliffs between Dover and Walmer some years ago, is described as of a clear milky-white colour, and has not, either on the upper or under side of the wings, the smallest speck of black. The ground colour is sometimes decidedly yellow, and very occasionally brownish.
The life-history of this butterfly is figured on Plate [74.]
The egg is whitish, opaque, with a dark speck on the apex; base flattened and slightly hollowed; finely reticulated, but without distinct striations or anything resembling ribs. The eggs are laid in July, and are not attached to anything.