1901.] 87

MOTH CATCHING BY ELECTRIC LIQHT AT THE BOER CAMP, DIYATALAWA, CEYLON.

BY E. ERNEST GREEN, F.E S., Governmrnt Emtosiolooiist.

At the invitation of one of the officers of the regiment guarding the Boer prisoners at Diyatalavva, I visited the camp to see the swarms of attracted each night by the powerful electric lamps erected round the Boer enclosure. I spent two nights at this work (December 15th and 16th), and had what was to me a most unique experience.

The Boer camp is situated in a small hollow in the midst of the undulating patna land at Diyatalawa, at an elevation of about 4000

feet. The electric lamps, of which there are 38, at an average dis- tance of 85 yards from each other, are visible from the surrounding

hills within a radius of about three miles, and where there are no hills

to interrupt the view, the glare of the lights must be noticeable from

a much greater distance. I am told that at Hakgala, some ten miles distant, the individual lights can be detected on a clear night. The

country for miles around is completely open, consisting of the wiry patna grass and the usual small patna plants. With the exception of a few small patches of scrub in an occasional hollow, there is no wooded land that could provide breeding ground for the myriads of

moths that are nightly attracted. The nearest forest is fully two

miles distant. Tet it is remarkable that the greater number of moths seen and captured are such as feed, in the larval stage, on plants and trees not present on the patnas.

The lamps, I am informed, are of the " Brockie Pell " pattern, each lamp of a nominal 2000 candle power. The standards, made of

sawn timber (7 in. by 7 in.), about 25 feet high, form an admirable resting place for the dazzled moths.

The lamps ai^e lighted at dusk which, at this season, is soon after

6 p.m , but it is some little time before the crowd assembles. The fun was in full swing when we started on our rounds at 9 o'clock.

From a little distance every lamp was seen to be surrounded by a whirling swarm of brilliantly illuminated objects. As we approached the grass was dotted with dazzled moths, and for several yards round the foot of the post the ground was simply carpeted with them. It became impossible to walk without treading upon them. The post

itself was encrusted with moths of all sizes, from the large Saturniids and Sphingids to the smallest Noetuids and Pyrales. Very few Tineids 88 f^P"^'

were noticed. On one sinsjle post I counted 39 specimens of the handsome hawk Vseudosphinx discistriga,\v\\\\e Daplinis hypofJwus and nessus almost rivalled the Pseudospltinx in numbers.

But b}'' far the most prominent species were the Noctuids, Oxyodes scrohiculata and Maceda mansueta. These two species were present in tens of thousands. The moths rested most thickly high up on the post close to the lamp. A pair of Zeiss's field-glasses proved most useful for scrutinizing this part of the post. It was a wonderful

sight to see all these handsome moths in such close proximity to each

other, the smaller species filling up the interstices between the wings

of the larger, or even superimposed upon them.

We found that a butterfly net was both inefficient and unnecessary. A better instrument was what we nickiumied the " tickler." It con- sisted of a long pole to the top of which was spliced a thin pliant twig, the whole resembling a fishing-rod. By careful manipulation the moths could be induced to transfer their hold to the twig and

could then be gently lowered to the ground, or, if dislodged, they merely fluttered down and allowed themselves to be handled and examined without attempting to escape. The three large killing

bottles with which I had provided myself were soon overcrowded, and resource was had to chloroform, a few drops of which, placed on the under surface of the largest moths, gave them their quietus, when they were folded in soft paper and put away in boxes with more of the chloroform to keep them asleep. Only strictly limited series were taken, and any individuals that showed interesting variations. Thou- sands of magnificent specimens (it was remarkable that nearly all the were in perfect condition) were left, though it is feared that few lived to repeat their frolic on the following night, and certainly none would return to their breeding grounds. Most of the lamps are set in the direct track of the sentries, and the heavy foot of the British soldier extinguished many a glorious specimen that would have gladdened the heart of an English entomologist. The path was decorated with a mosaic of variegated wings and bodies crushed into the mud.

I was surprised to find that on the occasion of my visit neither bats* nor goatsuckers were availing themselves of the feast that was ready for the taking. Only an occasional toad was deliberately load- ing itself up with the smaller moths that fluttered to the ground.

* Since writing the above, I hear that, on a subsequent occasion, bats were present in considerable numbers. 1 —

1901. 89

Several of these toads had fallen victims to the regimental boot and been added to the pattern impressed on the path. Others had iilled themselves to repletion and when touched turned over on their backs and gazed at the brilliant light in a condition of semi-hypnotism.

Some thirty lamps or more completed the circuit. Each one of these was visited in turn. The sentry-boxes also, built of white pinewood, amply repaid careful inspection. By the time the round

had been accomplished it was past midnight. I was warned, however,

that an early morning visit was advisable, before the crows, sparrows and swallows had commenced their work of destruction. So we started again at daybreak, and found the moths almost as we had left

them, exce])t that they were all at rest, and selection could be made with greater ense and deliberation. But now we were not the only collectors. An army of birds (sparrows and swallows, assisted by an occasional crow) was busily at work. The sparrows fluttered against the ])osts, knocking off a cluster of moths, and pounced on such as while exterminated those who tried fell to the ground ; the swallows to escape by flight. We amused ourselves by starting an occasional

flight of moths and observing how the swallows unerringly avoided

the several si)ecies that were protected by an offensive smell, such as Tlypsa compJnna, H. producfa and Pelochjfa astrea. This last insect, when handled, emitted a quantity of evil-smelling froth from each side of the prothorax. The same performance was repeated on the second night when,

if possible, an even larger assemblage of moths was present. It is

difiScult to understand whence such myriads of insects could be drawn each night, never to return to lay their eggs. A long continuance of these conditions must inevitably lead to the extinction of many species

from that district. The attraction has now been in force since the

middle of August last. The crowd is denser on some nights than on others. The moths do not assemble to any extent when a cold wind

is blowing, and strong moonlight is a deterrent. Warm damp nights, after rain, produce the heaviest crops.

It was particularly noticeable that very few purely local species were represented. In fact, Sangatissa suhcurvifera was almost the only moth that does not occur in the Kandy district (at half the elevation of Diyatalawa).

The following more striking species were noticed :

Sattjuniid.s; : Actias Selene, Hiibn. Bombycid.E : Ounda sikkima, Moore.

EUPTEKOTID.E : E. fancicUii, Moore ; Saiiffatissa suhcurvifera, Wlk. SnilNGiD^ : ;

90 [April,

Acherontia Lnchenis, Fabr. ; Chaerocampa Ce/erio, Linn, (this insect was found to

make a squeaking noise, much like the well known note of Acherontia) ; Daphtiis Hijpothous, Cram. ; Theretra Nessus, Drury ; Protoparce convoivuli, Linn., and Pseiidosphiiix disdstriga, Wlk. NOTODONTID^ : Stauropiis aUeriiii.i, Wlk., and Centra lilurafa, Wlk. CossiD^ : Duomitus leuconoius, Wlk., and Zeuzera post- excisa, [Impsn. Lasiocampid^: Trabala Vishnu, Lef. liYMAyiHiTyM: L. gr'ntdis,

Wlk. Arctiid^ : Chioncema subornata, Wlk., and Pelochyla astrea, Drury. N0CTUID.E : Arsilasisa plagiata^^lk.; Leociima sericea, Hinpsn. ; L. biplai/a,

Wlk. ; Callijna siderea, Guen. ; Ramadasa Pavo, Wlk. ; Hyhlcea coiistellata, Gnen. ; Bleniixi. donans and B. arcipiens,WW. ; Argi/rothripa i/risea, Umpsn. ; HypocaJa Moorei, Bull.; H. lativitta, Moore ; Patula macrops, Linn. ; I'olydesma leprom, Hmpsn. ; Ophiusa cuprea, Hmpsii.; Hypaetra «/;«>«/*.«, Moore ; Ischyia Manila, Cram.; Hamodes aurantiara, Gucn. (not previously recorded from Ceylon) ; Spirama retorta. Cram. ; Ophideres salaniniia, Fabr. ; O. ancilla. Cram., and O. fiiUonica, Linn. Amongst GEOMETRiDiE, the gem of the evening was Uliocnemis partita, VfW. (also new to Ceylon ). The PYiiAi.iDJi: were notably represented by

Pygospila Tyres, ; Cram. Neurina Procopia, Cram. ; Glj/phodes gIauct(laIis,Gium.

O. stolalis, Guen., and Bofiodes a.'dali.s-, Guen., with many less conspicuous species.

There were besides several novelties tliat I have not yet been able to determine.

Other Orders of insects, chiefly , were represented. The giant water-bug, Beloitoma indicum, was dashing about in every direction, while the brightly coloured incarnatus. anfl the stink-bug par excellence, Nezara niriduJa, were to be seen on every post. Scarabreids and water-beetles were attracted in considerable numbers, and a few specimens of the .inopheles mosquito were noticed.

With such results from only two nights' work, wliat could not a systematic collector, stationed on the spot, effect in the course of the year ? Each month would bring a partial change of species.

Some of the Boer prisoners have occupied their leisure in catching the moths that settle within their bounds, and have in this way amassed quite considerable collections. I noticed several rarities in their boxes, notably the large Eupterotid,

Apona sheiiarogensis, Moore. I also remarked a magnificent Noctuid, as large as, or even larger than, Patula macrops, which was quite unknown to me, and which I have been unable to recognise in "The Moths of British ." I tried to induce the wily Boer to sell, but money was no object to him, and he refused to part with his treasure for any consideration. He expressed his intention of sending his collection to his wife in London. Perhaps this apparently unique specimen may yet find its way to the British Museum. These men were working under great disadvantages. The lamps are outside the barrier, and only a small pereentage of the moths settle within their lines. Then they have to be within doors soon after sundown. They have no proper apparatus for collecting and preserving their specimens, but have manufactured for tlicmselvos rough setting-boards and store- boxes. In the face of all these difiieulties several collections of real merit have been formed.

Peradeniya, Ceylon : Februari/, 1901.