The Grayling (Satyrus Semele)
On the upper side, this butterfly (Plate 78) is brown, more or less suffused with black, and this is especially noticeable on the outer area of the wings in the male, where it obscures the ochreous or rust-coloured bands, which in the female are almost free from the suffusion. The fore wings have two black spots, the upper one generally, and the lower often, pupilled with white. On the hind wings the bands are clear of blackish suffusion to a greater or lesser extent, and there is one black spot towards the anal angle which may be pupilled with white. Apart from its larger size and brighter bands, the female may be distinguished from the male by the absence of the blackish brand on the disc of the fore wings. On the under side, the fore wings are ochreous, tinged with orange on the basal half or two-thirds; hind wings are greyish, with darker markings, and an irregular white or whitish band beyond the middle.
Variation is largely confined to the under side of the hind wings, and these wings, as well as the costal edge and the tips of the fore wings, are coloured and marked, in various localities that the butterfly affects, so that the insects may be protected from their enemies when resting.
On the upper side of the fore wings an additional spot is sometimes present below one or other of the usual ones. The bands of the wings are pale ochreous in some examples, and rust-coloured in others; but it is not unusual for a specimen with ochreous bands on the fore wings to have rust-coloured bands on the hind wings, or ochreous bands with rust-coloured patches on the outer portion; these patches are most frequently triangular in shape, and placed between the veins. Gynandrous specimens also occur, but very rarely.
The egg is of a dull creamy tint, ribbed, and with a slight depression on the top. The eggs were laid early in August, on blades and stems of a kind of grass; also on the leno covering, and the sides of the glass jar in which the female butterfly was enclosed.
The caterpillar when full grown “is drab, delicately mottled, with longitudinal stripes broadest along the middle segments, viz. a dorsal stripe of olive-brown, very dark at the beginning of each segment, with a thin edging of brownish-white. Along the subdorsal region are three stripes, of which the first is composed of a double narrow line of yellowish-brown, the second wider of the mottled ground colour, edged with paler above and with white below; the third of similar width is of a dark grey-brown, edged above with black. The spiracular stripe is broader and of nearly equal width, pale ochreous-brown, edged with brownish-white both above and below; the spiracles are black. The head is brown, and the principal stripes of the body are delicately marked with darker brown” (Buckler).
The chrysalis is described as “obtuse, rounded, tumid, and smooth, the abdominal rings scarcely visible, and wholly of a deep red mahogany colour.” It was “in a hollow space a quarter of an inch below the surface, the particles of sand and earth very slightly cohering together, and close to the roots of the grass, yet free from them.” The figures of caterpillar and chrysalis are drawn from those in Buckler’s “Larvæ of British Butterflies.”
The caterpillars hatch in August, hibernate when quite small, and feed up in the spring and early summer. They live upon grasses, such as Triticum repens, Aira cæspitosa, and A. præcox.
The butterfly delights in sitting rather than flying about cliffs and sand-hills, heaths and downs, stony hillsides, dry fields, and even open woodlands. It is fond of sunning itself on rocks, and by some of the old Aurelians it was called the “Rock Underwing,” no doubt in reference to the pattern and colour of the under side. It was also known as the “Tunbridge Grayling” some two hundred years ago, when it was said to be “very rare about London.” It has long since been ascertained to occur in almost every county in England and Wales, as far north as Sutherlandshire in Scotland, and is widely distributed in Ireland.
On the chalk downs and cliffs the butterfly has the under side of its hind wings so admirably agreeing in colour and marking with the soil, etc., that although one may watch it settle a few yards ahead, it is not to be seen when one reaches the spot. Whilst we are intent on the search the insect starts up, flies a short distance, and there repeats the disappearing butterfly trick. The same remarks apply to those Graylings that affect peaty or sandy heaths, etc. When the butterfly alights on the ground—and it rarely gets on the wing unless disturbed—it immediately closes its wings, and then allows them to fall more or less on one side, so that the whole of one hind wing is presented to view. It is said to have a fancy for the resinous sap that oozes from pine trees, and has also been observed to visit the trunks that have been “sugared.”
Abroad, it is found commonly throughout the temperate parts of Europe, North Africa, and Northern and Western Asia.