Sketches of the Natural History of Ceylon Part 45

_Planaria_.--In the journal already mentioned, Dr. Kelaart has given descriptions of fifteen species of planaria, and four of a new genus, inst.i.tuted by him for the reception of those differing from the normal kinds by some peculiarities which they exhibit in common. At Point Pedro, Mr. Edgar Layard met with one on the bark of trees, after heavy rain, which would appear to belong to the subgenus _geoplana_.[1]

[Footnote 1: "A curious species, which is of a light brown above, white underneath; very broad and thin, and has a peculiarly shaped tail, half-moon-shaped in fact, like a grocer's cheese knife."]

_Acalephae_.--Acalephae[1] are plentiful, so much so, indeed, that they occasionally tempt the larger cetacea into the Gulf of Manaar. In the calmer months of the year, when the sea is gla.s.sy, and for hours together undisturbed by a ripple, the minute descriptions are rendered perceptible by their beautiful prismatic tinting. So great is their transparency that they are only to be distinguished from the water by the return to the eye of the reflected light that glances from their delicate and polished surfaces. Less frequently they are traced by the faint hues of their tiny peduncles, arms, or tentaculae; and it has been well observed that they often give the seas in which they abound the appearance of being crowded with flakes of half-melted snow. The larger kinds, when undisturbed in their native haunts, attain to considerable size. A faintly blue medusa, nearly a foot across, may be seen in the Gulf of Manaar, where, no doubt, others of still larger growth are to be found.

[Footnote 1: Jelly-fish.]

[Ill.u.s.tration: PHYSALUS URTICULUS.]

Occasionally after storms, the beach at Colombo is strewn with the thin transparent globes of the "Portuguese Man of War," _Physalus urticulus_, which are piled upon the lines left by the waves, like globules of gla.s.s delicately tinted with purple and blue. They sting, as their trivial name indicates, like a nettle when incautiously touched.

_Red infusoria_.--On both sides of the island (but most frequently on the west), during the south-west monsoon, a broad expanse of the sea a.s.sumes a red tinge, considerably brighter than brick-dust; and this is confined to a s.p.a.ce so distinct that a line seems to separate it from the green water which flows on either side. Observing at Colombo that the whole area so tinged changed its position without parting with any portion of its colouring, I had some of the water brought on sh.o.r.e, and, on examination with the microscope, found it to be filled with _infusoria_, probably similar to those which have been noticed near the sh.o.r.es of South America, and whose abundance has imparted a name to the "Vermilion Sea" off the coast of California.[1]

[Footnote 1: The late Dr. BUIST, of Bombay, in commenting on this statement, writes to the _Athenaeum_ that: "The red colour with which the sea is tinged, round the sh.o.r.es of Ceylon, during a part of the S.W.

monsoon is due to the _Proto-coccus nivalis_, or the Himatta-coccus, which presents different colours at different periods of the year--giving us the seas of milk as well as those of blood. The coloured water at times is to be seen all along the coast north to Kurrachee, and far out, and of a much more intense tint in the Arabian Sea. The frequency of its appearance in the Red Sea has conferred on it its name."]

The remaining orders, including the corals, madrepores, and other polypi, have yet to find a naturalist to undertake their investigation, but in all probability the new species are not very numerous.

NOTE.

TRITONIA ARBORESCENS.

The following is the letter of Dr. Grant, referred to at page 385:--

Sir,--I have perused, with much interest, your remarkable communication received yesterday, respecting the musical sounds which you heard proceeding from under water, on the east coast of Ceylon. I cannot parallel the phenomenon you witnessed at Batticaloa, as produced by marine animals, with anything with which my past experience has made me acquainted in marine zoology. Excepting the faint clink of the _Tritonia arborescens_, repeated only once every minute or two, and apparently produced by the mouth armed with two dense h.o.r.n.y laminae, I am not aware of any sounds produced in the sea by branchiated invertebrata. It is to be regretted that in the memorandum you have not mentioned your observations on the living specimens brought you by the sailors as the animals which produced the sounds. Your authentication of the hitherto unknown fact, would probably lead to the discovery of the same phenomenon in other common accessible paludinae, and other allied branchiated animals, and to the solution of a problem, which is still to me a mystery, even regarding the _tritonia_.

My two living _tritonia_, contained in a large clear colourless gla.s.s cylinder, filled with pure sea water, and placed on the central table of the Wernerian Natural History Society of Edinburgh, around which many members were sitting, continued to clink audibly within the distance of twelve feet during the whole meeting. These small animals were individually not half the size of the last joint of my little finger.

What effect the mellow sounds of millions of these, covering the shallow bottom of a tranquil estuary, in the silence of night, might produce, I can scarcely conjecture.

In the absence of your authentication, and of all geological explanation of the continuous sounds, and of all source of fallacy from the hum and buzz of living creatures in the air or on the land, or swimming on the waters, I must say that I should be inclined to seek for the source of sounds so audible as those you describe rather among the pulmonated vertebrata, which swarm in the depths of these seas--as fishes, serpents (of which my friend Dr. Cantor has described about twelve species he found in the Bay of Bengal), turtles, palmated birds, pinnipedous and cetaceous mammalia, &c.

The publication of your memorandum in its present form, though not quite satisfactory, will, I think, be eminently calculated to excite useful inquiry into a neglected and curious part of the economy of nature.

I remain, Sir,

Yours most respectfully,

ROBERT E. GRANT.

_Sir J. Emerson Tennent, &c. &c._

CHAP. XII.

INSECTS.

Owing to the favourable combination of heat, moisture, and vegetation, the myriads of insects in Ceylon form one of the characteristic features of the island. In the solitude of the forests there is a perpetual music from their soothing and melodious hum, which frequently swells to a startling sound as the cicada trills his sonorous drum on the sunny bark of some tall tree. At morning the dew hangs in diamond drops on the threads and gossamer which the spiders suspend across every pathway; and above the pool dragon-flies, of more than metallic l.u.s.tre, flash in the early sunbeams. The earth teems with countless ants, which emerge from beneath its surface, or make their devious highways to ascend to their nests in the trees. l.u.s.trous beetles, with their golden elytra, bask on the leaves, whilst minuter species dash through the air in circles, which the ear can follow by the booming of their tiny wings. b.u.t.terflies of large size and gorgeous colouring, flutter over the endless expanse of flowers, and at times the extraordinary sight presents itself of flights of these delicate creatures, generally of a white or pale yellow hue, apparently miles in breadth, and of such prodigious extension as to occupy hours, and even days, uninterruptedly in their pa.s.sage--whence coming no one knows; whither going no one can tell.[1] As day declines, the moths issue from their retreats, the crickets add their shrill voices to swell the din; and when darkness descends, the eye is charmed with the millions of emerald lamps lighted up by the fire-flies amidst the surrounding gloom.

[Footnote 1: The b.u.t.terflies I have seen in these wonderful migrations in Ceylon were mostly _Callidryas Hilariae, C. Alcmeone_, and _C.

Pyranthe_, with straggling individuals of the genus _Euplaea, E. Coras_, and _E. Prothoe_. Their pa.s.sage took place in April and May, generally in a north-easterly direction. The natives have a superst.i.tious belief that their flight is ultimately directed to Adam's Peak, and that their pilgrimage ends on reaching the sacred mountain. A friend of mine travelling from Kandy to Kornegalle, drove for nine miles through a cloud of white b.u.t.terflies, which were pa.s.sing across the road by which he went.]

As yet no attempt has been made to describe the insects of Ceylon systematically, much less to enumerate the prodigous number of species that abound in every locality. Occasional observers have, from time to time, contributed notices of particular families to the Scientific a.s.sociations of Europe, but their papers remain undigested, and the time has not yet arrived for the preparation of an Entomology of the island.

What DARWIN remarks of the Coleoptera of Brazil is nearly as applicable to the same order of insects in Ceylon: "The number of minute and obscurely coloured beetles is exceedingly great; the cabinets of Europe can as yet, with partial exceptions, boast only of the larger species from tropical climates, and it is sufficient to disturb the composure of an entomologist to look forward to the future dimensions of a catalogue with any pretensions to completeness."[1] M. Nietner, a German entomologist, who has spent some years in Ceylon, has recently published, in one of the local periodicals, a series of papers on the Coleoptera of the island, in which every species introduced is stated to be previously undescribed.[2]

[Footnote 1: _Nat. Journal_, p. 39.]

[Footnote 2: Republished in the _Ann. Nat. Hist._]

COLEOPTERA.--_Buprestidae; Golden Beetles_.--In the morning the herbaceous plants, especially on the eastern side of the island, are studded with these gorgeous beetles, whose golden wing-cases[1] are used to enrich the embroidery of the Indian zenana, whilst the l.u.s.trous joints of the legs are strung on silken threads, and form necklaces and bracelets of singular brilliancy.

[Footnote 1: _Sternocera Chrysis; S. sternicornis_.]

These exquisite colours are not confined to one order, and some of the Elateridae[1] and Lamellicorns exhibit hues of green and blue, that rival the deepest tints of the emerald and sapphire.

[Footnote 1: Of the family of _Elateridae_, one of the finest is a Singhalese species, the _Campsosternus Templetonii_, of an exquisite golden green colour, with blue reflections (described and figured by Mr.

WESTWOOD in his _Cabinet of Oriental Entomology_, pl. 35, f. 1). In the same work is figured another species of large size, also from Ceylon, this is the _Alaus sordidus_.--WESTWOOD, l. c. pl. 35, f. 9.]

_Scavenger Beetles_.--Scavenger beetles[1] are to be seen wherever the presence of putrescent and offensive matter affords opportunity for the display of their repulsive but most curious instincts; fastening on it with eagerness, severing it into lumps proportionate to their strength, and rolling it along in search of some place sufficiently soft in which to bury it, after having deposited their eggs in the centre. I had frequent opportunities, especially in traversing the sandy jungles in the level plains to the north of the island, of observing the unfailing appearance of these creatures instantly on the dropping of horse dung, or any other substance suitable for their purpose; although not one was visible but a moment before. Their approach on the wing is announced by a loud and joyous booming sound, as they dash in rapid circles in search of the desired object, led by their sense of smell, and evidently little a.s.sisted by the eye in shaping their course towards it. In these excursions they exhibit a strength of wing and sustained power of flight, such as is possessed by no other cla.s.s of beetles with which I am acquainted, but which is obviously indispensable for the due performance of the useful functions they discharge.

[Footnote 1: _Ateuchus sacer; Copris sagax; C. capucinus_, &c. &c.]

[Ill.u.s.tration: LONGHORN BEETLE (BATEROCERA RUBUS).]

_The Coco-nut Beetle_.--In the luxuriant forests of Ceylon the extensive family of _Longicorns_[1] and _Pa.s.salidae_ live in destructive abundance.

To the coco-nut planters the ravages committed by beetles are painfully familiar.[2] The larva of one species of _Dynastida_, the _Oryctes rhinoceros_, called by the Singhalese "_Gascooroominiya_," makes its way into the younger trees, descending from the top, and after perforating them in all directions, forms a coc.o.o.n of the gnawed wood and sawdust, in which it reposes during its sleep as a pupa, till the arrival of the period when it emerges as a perfect beetle. Notwithstanding the repulsive aspect of the large pulpy larvae of these beetles, they are esteemed a luxury by the Malabar coolies, who so far avail themselves of the privilege accorded by the Levitical law, which permitted the Hebrews to eat "the beetle after his kind."[3]

[Footnote 1: The engraving on the preceding page represents in its various transformations one of the most familiar and graceful of the longicorn beetles of Ceylon, the _Batocera rubus_.]

[Footnote 2: There is a paper in the _Journ. of the Asiat. Society of Ceylon_, May, 1845, by Mr. CAPPER, on the ravages perpetrated by these beetles. The writer had recently pa.s.sed through several coco-nut plantations, "varying in extent from 20 to 150 acres, and about two to three years old: and in these he did not discover a single young tree untouched by the cooroominiya."--P. 49.]

[Footnote 3: Leviticus, xi. 22.]

Amongst the superst.i.tions of the Singhalese arising out of their belief in demonology, one remarkable one is connected with the appearance of a beetle when observed on the floor of a dwelling-house after nightfall.

The popular belief is that in obedience to a certain form of incantation (called _cooroominiya-pilli_) a demon in the shape of a beetle is sent to the house of some person or family whose destruction it is intended to compa.s.s, and who presently falls sick and dies. The only means of averting this catastrophe is, that some one, himself an adept in necromancy, should perform a counter-charm, the effect of which is to send back the disguised beetle to destroy his original employer; for in such a conjuncture the death of one or the other is essential to appease the demon whose intervention has been invoked. Hence the discomfort of a Singhalese on finding a beetle in his house after sunset, and his anxiety to expel but not to kill it.

_Tortoise Beetles_.--There is one family of insects, the members of which cannot fail to strike the traveller by their singular beauty, the _Ca.s.sididae_ or tortoise beetles, in which the outer sh.e.l.l overlaps the body, and the limbs are susceptible of being drawn entirely within it.

The rim is frequently of a different tint from the centre, and one species which I have seen is quite startling from the brilliancy of its colouring, which gives it the appearance of a ruby enclosed in a frame of pearl; but this wonderful effect disappears immediately on the death of the insect.

ORTHOPTERA. _Leaf-insects_.--But in relation to the insects of Ceylon the admiration of their colours is still less exciting than the astonishment created by the forms in which some of the families present themselves; especially the "soothsayers" (_Mantidae_) and "walking leaves." The latter[1], exhibiting the most cunning of all nature's devices for the preservation of her creatures, are found in the jungle in all varieties of hues, from the pale yellow of an opening bud to the rich green of the full-blown leaf, and the withered tint of decay. So perfect is the imitation of a leaf in structure and articulation, that this amazing insect when at rest is almost undistinguishable from the foliage around: not only are the wings modelled to resemble ribbed and fibrous follicles, but every joint of the legs is expanded into a broad plait like a half-opened leaflet.