136 FAMILY BOSTRYCHIDAE 



for use as a field telegraph during the approaching Tibet Mission. It 

 was imperative that the bamboos so employed should remain immune to 

 the attacks of the beetles, which would otherwise reduce them to powder 

 within a comparatively short period, and long ere they reached an elevation 

 where the temperature would either kill the beetles or (more probable) 

 so lower their vitality and that of the grubs as to reduce very considerably 

 their activity. 



The experiments carried out consisted in placing in beetle-proof boxes 

 a number of lengths of infested bamboo taken from the workshops either 

 untreated or thoroughly soaked in water for several days, soaked in water 

 and then in a solution of copper sulphate, and lastly soaked in water, copper 

 sulphate, and Rangoon oil, the latter from twenty-four to forty-eight hours, 

 and watching the effects of the beetles' attacks on them. Lengths of bamboo 

 thoroughly soaked in water, copper sulphate, and Rangoon oil were also 

 placed amongst lengths of badly infested bamboos in the open, with a view 

 to further testing their immunity from attack. 



The following deductions may, I think, be considered as established by the above 

 experiments : 



Results of (i) That neither the five days in water nor that followed by a 



Treatment. further five days in CuSO 4 are of any use as a protection against the 



beetles. It is true that Experiments II and III seemed at first to 



prove that these soakings were effective, since the bamboos in these boxes remained un- 

 attacked. I attribute this, however, solely to the fact that the pieces of bamboos, selected 

 at haphazard in the Telegraph Workshops, and placed in the closed boxes in April when the 

 beetles were egg-laying, did not happen to have had eggs deposited in them, and consequently 

 when they were placed in the beetle-proof boxes and protected against any future depositions 

 of eggs in them they showed no attacks. All the subsequent experiments with these classes 

 of treatment showed that they afford no protection against the beetles. 



(2) That the bamboos which had gone through all the stages of the treatment and had 

 received a proper soaking in the oil tank remained unattacked, and in addition were proof 

 against further attacks by the beetles. 



(3) That at least five generations of these beetles issued between the last week in April 

 and the end of October, as detailed above. 



(4) That bamboos cut in the forests between December and February can, even if not 

 treated till two or three months have elapsed since cutting (by which time it is probable 

 that many of them will contain eggs), be preserved by the oil treatment from further 

 attacks of the beetle-borer. Bamboos unprotected by the oil treatment are tunnelled 

 into by the April, June, July, September, and October generations of beetles, each of 

 which attacks means their subsequent riddling by the larvae arising from the eggs laid by 

 the beetles. 



(5) That the oil treatment therefore considerably prolongs the period of usefulness 

 of the bamboo, this period being, as far as the experiments at present show, at least 

 a year. 



(a) I am inclined to recommend that the soaking for five days in water should 

 be continued, since a thick, shiny, gelatinous substance exudes 



Recommendations. from the bamboos during this process, and this exudation prob- 

 ably enables the bamboo to absorb a larger quantity of oil than 

 would be otherwise the case. 



