Its range extends throughout the British Islands, and seems to be very similar to that of the Painted Lady.
The Silver-washed Fritillary (Argynnis paphia).
The wings of this fine butterfly are fulvous, with the veins and spots black; the spots on the hind wings are band-like, and the central spots on the fore wings are sometimes connected. The female is paler than the male, and is without the heavy black scales (androconia) on veins 1, 2, and 3; the basal third of the fore wing, and a larger area of the hind wing, tinged with greenish. The form of the female with all the wings greenish is the var. valesina (Plate [52]), and between this and the type there are various intergrades, one of which is shown on the plate. Specimens with white spots on the fore wings, and chiefly in the males, are sometimes not uncommon in the New Forest, as, for instance, in the year 1893, when quite a large number were secured. Very much more rarely white spots occur on all the wings (Plate [57,] Fig. [1]). In a very remarkable male specimen, taken in the New Forest in 1881, the central area of all four wings is black, and the veins beyond are broadly edged with the same colour. A curious female aberration has the central black spots much reduced or absent, whilst those on the outer margin are united, and form elongate blotches between the veins, the upper one being wedge-shaped. Aberrations of the valesina form, similar to that figured on Plate [57,] Fig. [2,] and Fig. [25] on next page, are not often met with; the ground colour is greenish, but much suffused and clouded with black. Now and then gynandrous specimens are obtained, the one side normal male and the other side typical female, or var. valesina.
The egg when newly laid, in July, is whitish tinged with green, ribbed, and cross-furrowed, the alternate ribs not extending to the top. As the caterpillar matures, the egg-shell appears blackish and the ribs hoary.
The caterpillar when full grown is velvety black with two bright yellow lines along the back; the spines are of a reddish-ochreous colour with the extreme tips and branches black. There are only two on the first ring, and these are inclined forward over the head. The chrysalis is of a pale ochreous colour, streaked and mottled with brownish; the hollow part of the back has a brilliant golden sheen, and the points on the rest of the body are gold tipped. Suspended by the anal hooks to a silken pad spun on a twig, rock, or other object in the vicinity of its feeding-place, it is capable of much activity in the way of wriggling when touched, and displays the beauty of its metallic adornment to the greatest advantage when so engaged.
The caterpillar hatches in August, and after eating its egg-shell and nibbling a leaf or two of dog-violet (Viola canina), goes into winter quarters whilst in its second skin, and consequently very small; the spines, which are such an imposing feature of the adult caterpillar, have not yet appeared. In April, after feeding again, it moults the second time, and the spines are then disclosed.
Sometimes caterpillars continue to feed in the autumn instead of hibernating. This, at least, has happened to Mr. Frohawk on two occasions, notably in 1893, when he had several individuals of a brood, from eggs laid by a female of the valesina form, that departed from the usual custom of their kind by feeding and growing until they eventually passed through all the stages and emerged perfect butterflies in September and October of that year. Something similar occurred in a brood that he was rearing in the autumn of 1895, but on this occasion only one caterpillar continued to feed beyond the normal time.
The English name by which we now know this, the largest of the six British Argynnids, seems to have been given to it by Moses Harris in 1778. Sixty years or so before that date it was called the "Greater Silver-streaked Fritillary." Fortunately, in this case, as in others where the vulgar tongue is entomologically concerned, the law of priority does not apply, so that the name Silver-washed, which so well expresses the underside ornamentation, may be retained.
