Pl. 51.
Silver-washed Fritillary.
Egg, natural size and enlarged; caterpillar and chrysalis.
Abroad, the typical form is distributed through Europe and Asia to China, Corea, and Japan. The valesina variety is uncommon in Northern Europe, but in some parts of China it seems to be the dominant form.
The High Brown Fritillary (Argynnis adippe).
Bright fulvous with black spots and veins. The female is not so bright in tint as the male, and is without the thick patch of scales on veins 2 and 3. The series of black spots parallel with the outer margin of the fore wing are normally six in number, but the third is usually small and sometimes absent, whilst the fourth and fifth are often much larger than others of the series. In the corresponding row on the hind wing the first and third spots are sometimes wanting. On the under side the silvery spots are generally as seen in Plate [54,] but they are subject to modification, and not infrequently are absent from the tips of the fore wings, and sometimes from the outer margin of the hind wings also. A very rare aberration has the central area of the fore wings black on the upper and under sides; the hind wings are black above with fulvous lunules on the outer margin, and the silvery spots on the under side are reduced to five, and these are confined to the basal area. In another remarkable form the hind wings above are similar to the last-mentioned variety, but on the under side the silvery spots on the basal half are united and form a large patch, which is divided by the nervures, and there are no silvery spots on the outer margin. The variety shown on Plate [57] has the under side of the hind wings buff in colour, the markings on the outer margin are reddish-brown with a few silvery scales towards the anal angle, and the basal silvery spots are confluent, agreeing in the latter character with the preceding variety, and also with var. charlotta of the next species. In var. cleodoxa the spots on the under side are yellowish instead of silvery, but the red spots on the outer area are sometimes silver centred; this form is only rarely found in Britain. Possibly some of the reputed British examples of A. niobe may have been referable to cleodoxa, but what appears to be more certain is that the actual occurrence of niobe in England is exceedingly doubtful.
The egg when newly laid is yellowish-green; it afterwards turns pink, and then rosy red; during the winter it changes to greyish or bluish-green. As a rule, the eggs are laid at the end of July, and the caterpillars do not hatch until the following March or early in April. In 1893, however, Mr. Frohawk had a few caterpillars hatch out between the middle of August and September 20, from a number of eggs laid at the end of June. One of these, fed up, pupated on October 13, and the butterfly emerged on November 21. The majority of the eggs remained over to the following spring. According to an observation made by Mr. W.H.B. Fletcher, the caterpillar is fully formed soon after the egg is laid, but remains within the shell all the winter.
The caterpillar, which feeds upon dog-violet, and also the sweet violet, is figured on Plate [53.] The head is pinkish-brown, covered with short greyish bristles. Body black, incrusted with ochreous grey on the sides, and on the back marked with ochreous grey on the hinder half of each ring; dorsal line white. The branched spines are pinkish-brown.