The Comma (Polygonia C-Album)
The peculiar shape of the wings of this butterfly (Plate 35) might cause it to be mistaken for a very tattered example of one of the Tortoiseshells. The irregular contour of the outer edges of the wings is, however, quite natural, and is subject to some variation in its jaggedness. Their colour is deep tawny or fulvous, with brownish borders on their outer margin. On the fore wings there are three black spots on the front or costal area, and below the first, which is often divided, there is a roundish black spot (sometimes double) just above the inner margin; two, sometimes three, other spots lie between this and the third costal spot. On the hind wings there are three black spots on the basal half, and a series of pale fulvous spots before the brownish border; these are inwardly edged with brownish, and sometimes this edging is united with the marginal border. Similar spots are, in some specimens, present in a like position on the fore wings also. On the under side the wings are of various shades of brown, sometimes variegated with whitish, or yellowish, and greenish, the latter often conspicuous; other specimens are paler on the outer half than on the basal half, and, except occasionally having a series of greenish or dusky spots on the outer area, are without marking. These differences occur in both sexes. The white comma or c mark, placed about the middle of the under side of the hind wings, is rather stronger in the variegated specimens; but it varies, generally, in shape as well as in size.
Var. hutchinsoni, Robson, which has been renamed pallida and lutescens, differs from the typical form in having the ground colour much lighter and brighter on the upper side and ochreous on the under side. It is shown on Plate 35. The outline of the wings of this form, which occurs in June and July, is said to be less jagged, and this may be so as a rule, but it certainly is not always the case. Possibly this is “The Pale Comma” of Petiver.
There are two broods of this species in the year, but the first or summer flight of butterflies seems to depend upon a favourable season, as also does the second or autumnal brood, at least as regards the number of butterflies representing it. The late butterflies hibernate and reappear in April, or even March, of the following year. It has been stated that all the specimens appearing in the spring are of the form with plain under sides.
From eggs laid between April 27 and May 6, Miss E. Hutchinson, writing in 1887, says caterpillars hatched between 5 and 11. They were “fed” on currant and nettle mixed, and were full grown from June 17th till the 23rd. The first butterfly emerged on June 26, and the last on July 3, and all were very fine and of the pale summer variety. Two of the insects paired on June 30, and the female commenced laying on July 1, and continued doing so till the 10th, when there were 120 ova. Unfortunately, a very cold spell of weather began on July 12, and more than half the eggs perished. The butterflies resulting from the remainder appeared during August, from the 17th to the 27th, but they would not pair, probably because, although they had emerged at an early date, they properly belonged to the autumnal flight.
In 1894 Mr. Frohawk reared 200 of these butterflies from 275 eggs laid by a female between April 17 and June 1 of that year. The caterpillars were supplied with nettle only. The first butterfly emerged on June 30, and the last on August 2. Of the whole number forty-one were of the light fulvous form, var. hutchinsoni, and all the others of the dark or typical form. With few exceptions, the light-coloured butterflies were the first to emerge, and the major portion of these during early July, and before any examples of the dark form had come out.
The egg is at first green in colour with ribs whiter, but changes before the caterpillar hatches out to yellowish. In confinement the female butterflies deposit their eggs singly or in chains of three or four; probably the latter is the usual method of laying the eggs under natural conditions.
The caterpillar when full grown is black, netted with greyish; the spines on the second to fifth rings inclusive are yellowish, and those on the back of the other rings are white; the back from ring 6 to ring 10 inclusive is broadly white, marked with black, and the upper surface of the other rings is more or less yellowish. The head is black, marked with ochreous; the crown is lobed, and on each lobe is a short club-like knob.
The chrysalis is brownish tinged with pink; the wing-cases and the rings of the body are edged with blackish; there is a greyish line along the back of the body and a brownish stripe along the spiracles; at the point where the body joins the thorax there are some silvery or golden spots. The figures of caterpillar and chrysalis on Plate 32 are after Buckler.
This butterfly seems to have disappeared from many localities in England where it formerly flourished. About seventy or eighty years ago, for example, it was plentiful in Epping Forest, in Herts, and in Dorset. During the last half-century or so it has been common in certain parts of many of the counties from Somerset to Durham and Cumberland, but seems to have occurred only sparingly or singly in Norfolk, Suffolk, Essex, Kent, Sussex, Hants, Wilts, and Devon. It still occurs now and then in the Dover district, the most recent record being of one taken in October, 1894; and it was reported from North Staffordshire in 1893. Probably it is now almost entirely confined to favoured districts embraced within the area represented by the counties of Herefordshire, Worcestershire, and Monmouthshire, whence it may occasionally stray into the adjoining counties, or even further afield.
This butterfly is often associated with hop gardens, but it is by no means restricted to such places. The usual food-plants of the caterpillars are hop (Humulus lupulus), nettle (Urtica dioica), and currant (Ribes), but it is reported to eat gooseberry (R. grossularia) and elm (Ulmus).
Abroad it has a very wide distribution in Europe, and extends through Asia to Japan.