ABOUT DEATH’S-HEADS.
Probably, at some time or other, the reader has found feeding upon the leaves of potatoes a large green, yellowish green, or brown creature about the thickness of his finger, with seven dark purple and yellow-margined streaks upon the sides, and the dorsal portion decorated with black dots; the tail-end, moreover, being adorned with a ‘caudal appendage’ somewhat resembling a lamb’s tail in miniature, save that it is rigid, and not woolly; or it may be that in digging up the crop, if the owner of a garden, he has turned up a reddish-brown ‘grub,’ which, beyond a jerk or two with the pointed tail segments, seemed incapable of motion. The fate of these creatures is generally a sad and sudden one, if the finder happen to be the rustic unlearned in insect-life. ‘Here be a locust; dang the beast!’ and down comes the merciless iron heel, and behold, a shapeless mass! Yet the poor things were harmless enough, and known to the entomologist as, in the one case, the larva or caterpillar, and in the other, the pupa, of the Death’s-head Moth (Acherontia atropos).
Most years seem remarkable for the prevalence of some particular forms of insect-life. For instance, in 1877, clover fields teemed with golden butterflies, which soon spread into high-roads, and even town gardens. These were the Clouded Yellow (Colias edusa), since which only sparingly has the butterfly been seen. Then, in 1879, came swarms of Silver Y Moths (Plusia gamma), the caterpillars of which played sad havoc with the farmer’s peas, completely stripping them of leaves—to plants, both as lungs and stomach—so that the peas never ripened in the pod. But nature, as we speak, had provided a remedy in the form of flocks of thrushes, which ‘fared sumptuously every day’ upon the larvæ; and yet so ignorant was the farmer of the help his little feathered friends were rendering him, that he attributed the mischief to ‘them rascally birds,’ and was for ‘shooting them all off.’
Some seasons, the beans in our gardens are thickly covered with insects (Aphis rumicis), and ants may be watched busily plying their antennæ, and milking their aphis cows, and sipping up the exuded nectar-like fluid with a gusto an epicure might envy. Or, it may be the pendulous racemes of the Sycamore (Acer pseudoplatanus) look as if dipped in ink from the swarms of a sable dipteron, or fly (Dilophus febrilis), thickly aggregated thereon. And last year we had clouds of green-flies—another species of aphis—migrating, in some places even almost stopping traffic, and, in one little town in the south of England, extinguishing the lights in the post-office, and filling eyes, ears, noses, and mouths of the officials to the serious impediment of their duties. So, too, the season of 1885 proved a good one, as the lepidopterist would say, for the larvæ of the Death’s-head Moth, in fact, it is doubtful if it had ever been so abundant. It is a grand species—the largest of our native Sphingidæ, or Hawk Moths, and interesting in all stages of its existence. It is the only lepidopteron that we possess capable of making any cry; but the caterpillar, pupa, and moth of Atropos can all squeak. In putting the moths into a comatose state, prior to consigning them to the ammonia bottle—when needing to kill them for the cabinet—I have applied a camel-hair brush dipped in chloroform to the proboscis, holding them by finger and thumb by the under side of the wings, so as not to disfigure their beauty, I have been surprised at the muscular power exhibited, it being all I could do to prevent their escaping, the insect the while squeaking as loudly as a poor mouse whilst suffering from the tender mercies of Puss.
The caterpillars are not easy to find. We may go over ridge by ridge of the potatoes and not see one, so well hidden are they by protective resemblance to the plants upon which they feed; the colours of the leaves and flowers of the potato, for example, the dark violet petals, and yellow anthers, all being reproduced in the caterpillar. The best and quickest way to discover them is to search for the traces of their repasts, which are collected in little heaps at the bottom of the plant; and if these be fresh, we may be confident that a little scrutiny will speedily reveal an obese, soft larva tightly clasping the stem. The larvæ are found throughout August; and about the beginning of September are full-fed, when they bury beneath the soil, forming a cell in which they turn to pupæ. Sometimes the moth emerges in October or November; but such specimens are generally barren females, and the insect usually remains in pupa condition throughout the winter, coming out about midsummer of the following year.
The moth or imago of Acherontia atropos is very handsome; the upper wings have a velvety appearance, the colours being an extremely rich mixture of browns and black and gray, thickly powdered with whitish dots. The lower wings are orange, with two dusky bands crossing from the inner to the hind margin. In the centre of the dark plush-like thorax is a mark curiously resembling a skull, from which the moth takes its name. The body is very thick, with six or seven black transverse bands, and a broad bluish-gray one down the middle. They have a strong penchant for honey, to secure which, they will enter beehives, putting the bees to flight by their bold front, although perfectly defenceless themselves. There is a superstition still lingering in some parts of the New Forest that the Death’s-head Moth was not seen in England till after the execution of Charles I.