Conspicuous amidst these nocturnal moths is the richly-coloured Acherontia Satanas, one of the Singhalese representatives of our Death's head moth, which utters a sharp and stridulous cry when seized. This sound has been variously conjectured to be produced by the friction of its thorax against the abdomen, and Reaumur believed it to be caused by rubbing the palpi against the tongue. I have never been able to observe either motion, and Mr. E. L. Layard is of opinion that the sound is emitted from two apertures concealed by tufts of wiry bristles thrown out from each side of the inferior portion of the thorax.[1]
1: There is another variety of the same moth in Ceylon which closely resembles it in its markings, but I have never detected in it the utterance of this curious cry. It is smaller than the A. Satanas, and, like it, often enters dwellings at night, attracted by the lights; but I have not found its larvæ, although that of the other species is common on several widely different plants.
Moths.—Among the strictly nocturnal Lepidoptera are some gigantic species. Of these the cinnamon-eating Atlas, often attains the dimensions of nearly a foot in the stretch of its superior wings. It is very common in the gardens about Colombo, and its size, and the transparent talc-like spots in its wings cannot fail to strike even the most careless saunterer. But little inferior to it in size is the famed Tusseh silk moth[1], which feeds on the country almond (Terminalia catappa) and the palma Christi or Castor-oil plant; it is easily distinguishable from the Atlas, which has a triangular wing, whilst its [wing] is falcated, and the transparent spots are covered with a curious thread-like division drawn across them.
1: Antheroea mylitta, Drury.
Towards the northern portions of the island this valuable species entirely displaces the other, owing to the fact that the almond and palma Christi abound there. The latter plant springs up spontaneously on every manure-heap or neglected spot of ground; and might be cultivated, as in India, with great advantage, the leaf to be used as food for the caterpillar, the stalk as fodder for cattle, and the seed for the expression of castor-oil. The Dutch took advantage of this facility, and gave every encouragement to the cultivation of silk at Jaffna[1], but it never attained such a development as to become an article of commercial importance. Ceylon now cultivates no silkworms whatever, notwithstanding this abundance of the favourite food of one species; and the rich silken robes sometimes worn by the Buddhist priesthood are still imported from China and the continent of India.
1: The Portuguese had made the attempt previous to the arrival of the Dutch, and a strip of land on the banks of the Kalany river near Colombo, still bears the name of Orta Seda, the silk garden. The attempt of the Dutch to introduce the true silkworm, the Bombyx mori, took place under the governorship of Ryklof Van Goens, who, on handing over the administration to his successor in A.D. 1663, thus apprises him of the initiation of the experiment:—"At Jaffna Palace a trial has been undertaken to feed silkworms, and to ascertain whether silk may be reared at that station. I have planted a quantity of mulberry trees, which grow well there, and they ought to be planted in other directions."—VALENTYN, chap. xiii. The growth of the mulberry trees is noticed the year after in a report to the governor-general of India, but the subject afterwards ceased to be attended to.
In addition to the Atlas moth and the Mylitta, there are many other Bombycidoe in Ceylon; and, though the silk of some of them, were it susceptible of being unwound from the cocoon, would not bear a comparison with that of the Bombyx mori, or even of the Tusseh moth, it might still prove to be valuable when carded and spun. If the European residents in the colony would rear the larvæ of these Lepidoptera, and make drawings of their various changes, they would render a possible service to commerce, and a certain one to entomological knowledge.
The Wood-carrying Moth.—There is another family of insects, the singular habits of which will not fail to attract the traveller in the cultivated tracts of Ceylon—these are moths of the genus Oiketicus,[1] of which the females are devoid of wings, and some possess no articulated feet; the larvæ construct for themselves cases, which they suspend to a branch frequently of the pomegranate,[2] surrounding them with the stems of leaves, and thorns or pieces of twigs bound together by threads, till the whole presents the appearance of a bundle of rods about an inch and a half long; and, from the resemblance of this to a Roman fasces, one African species has obtained the name of "Lictor." The German entomologists denominated the group Sack-träger, the Singhalese call them Dalmea kattea or "billets of firewood," and regard the inmates as human beings, who, as a punishment for stealing wood in some former stage of existence, have been condemned to undergo a metempsychosis under the form of these insects.
1: Eumeta, Wlk.
2: The singular instincts of a species of Thecla, Dipsas Isocrates, Fab., in connection with the fruit of the pomegranate, were fully described by Mr. Westwood, in a paper read before the Entomological Society of London in 1835.