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The only remedial measures suitable for natives seem to be preventive. 

 Those generally advised are embodied in ordinances containing the 

 following instructions : — The uprooting, burning or burying 3 feet deep 

 of palm stumps ; the destroying of coconut trunks by cutting or 

 burning, keeping under water or buiying at least 3 feet deep ; the 

 burning of all vegetable refuse ; the regular searching of dung-heaps 

 and the killing of the grubs, etc., found therein. These instructions 

 are incomplete, as they omit the large refuse heaps of towns and bridges 

 constructed of coconut stems. Furthermore, some of them are not 

 feasible. Too much labour is needed to dig up the coconut stumps, 

 and to bury stumps and trunks 3 feet deep or to burn them is too 

 difficult a task in practice. Incompletely burnt refuse attracts the 

 larvae of Oryctes, and it was therefore imperative to find a more efficient 

 method. Whoever originally prescribed the burying at a depth of 

 3 feet evidently did not know what depth was actually required. 

 In tests to find the actual thickness of the covering of sand or soil 

 needed to prevent the beetles from detecting a breeding place, pits were 

 filled with uninfes'ted vegetable rubbish, and every alternate pit was 

 covered with a top dressing of sand varying between 19 and 4 inches 

 in thickness. In 77 experiments not one beetle, larva or egg of 

 0. rhinoceros was ever found in the covered pits, whereas the open pits 

 contained 222 eggs, 5,713 larvae, and 78 beetles. There is therefore 

 no doubt that even a thin layer of sand prevents the beetles from locating 

 an attractive breeding place. These experiments were followed by a 

 practical test at Padang on an area of over \ acre which was 

 covered with a layer of vegetable refuse over which a layer of sand 

 from 2 to 7 inches thick was spread within a fortnight. After 4| 

 months not a single beetle or larva was found, not even in places where 

 only a few inches of sand had remained. A layer of 8 inches of sand, 

 or other soil without humus, is therefore sufficient to prevent breeding. 

 Communal refuse (where it cannot be incinerated) may be used to 

 improve marshy land near towns, provided it is covered in this manner. 



Direct measures for combating 0. rhinoceros may be divided into 

 those against the beetles and those against the larvae. For filling the 

 hole after killing or removing the beetle with a piece of wire, the author 

 used with success a mixture of 1 part coarse salt and 2 parts sea 

 sand and then closed the hole with clay. Experiments with light-traps 

 were negati\'e, as also were attempts at trapping by means of husks 

 of young nuts suspended in the trees. The best measure against the 

 larvae is to catch them in trap-heaps as already described. The heaps 

 must be searched at intervals not exceeding 3 months, and it is 

 better to examine them every 6 or 8 weeks. In damp chmates 

 the placing of the heaps in cool positions is unnecessar}-, nor is a roof 

 required. Fumigation with carbon bisulphide is possible, but as 

 about 10 liuid oz. are required per 35 cu. ft., its advantages are rather 

 doubtful. Ver^^ successful results were achieved by adding sodium 

 arsenite and Paris green to the traps. It was found that \ per cent, 

 of these substances did not affect the attractiveness of the bait for the 

 beetles, and though normal oviposition occurred, no larvae developed. 

 As, however, these poisons remain active even after nine months, 

 the material cannot be used for manure during an even longer period. 

 For this reason experiments were made with saltpetre and ammonium 

 sulphate, but they pro\-ed inferior, as also did lead arsenate. In 

 experiments in starving the larvae, full-grown examples remained alive 

 for 16i days, and full-grown individuals that had been starved for 

 13 days became quite normal after feeding for a iew days. 



