300 



mite activity. In the tropics where termite hfe reaches its high- 

 est expression some animals habitually depend upon termites 

 for their sustenance and are peculiarly adapted to this means of 

 li\-elihood. Birds like the swifts also find a ready and abundant 

 supply of food in the great swarms of colonizing individuals 

 emerging as a seasonal occurrence from the large nests which 

 many tropical species form. But these agencies by \^liich 

 nature exerts a check on excessive multiplication of termites ap- 

 pear impractical for our purposes. In discussing the enemies of 

 termites we must not overlook the ants, which are most persistent 

 foes of termites and in the case of the aggressive carnivorous 

 species make havoc in any termite nest to which they can gain 

 access. They undoubtedly exercise a great check on the termites 

 here particularly upon colonization but the vast numbers in which 

 termites exist and the abundant supply of food together with 

 the self -containment of their nests give a great advantage to the 

 termites in the struggle for life. 



Artificial control. Two courses are open to pursuit in at- 

 tempting a control by artificial means,, viz. : (1) The reduction 

 of the termites by the destruction of their nests or termitaria. 

 (2) Reduction of the termites by depriving them of their sus- 

 tenance. The latter naturally would be an anticipatorv or prc- 

 \entive measure as far as damage is concerned. 



1. Destruction of nests or termitaria. Probably the best 

 method of accomplishing this purpose is by fumigation with car- 

 bon bisulphide, hydrocyanic acid gas or the fumes derived from 

 the burning of arsenic and sulphur. The location of the nest 

 would be an important consideration in fumigation particularly 

 as the gases require concentration to be effective. It is not be- 

 lieved that fumigation can be applied to the treatment of houses 

 where the nests (of Kaloteniics and Cryptotcniies) are in the 

 walls or supports, but articles of furniture can be effectively 

 treated in a fumigatorium. If the house is attacked by Copto- 

 fcrmcs the nest should.be sought for treatment. 



2. Anticipatory or preventive methods. These imply the 

 suitability of termite-proof materials and the possibility of ren- 

 dering materials termite-proof by treatment. The most recent 

 and thorough investigations in this direction were made by 

 Oshima in Formosa.^^ His conclusion is that nothing except iron 

 and stone is absolutely safe from the attacks of termites. He 

 recommends the general substitution of concrete for wood and 

 gives elaborate plans for the construction of termite-proof build- 

 ings. Numerous experiments were made to determine the de- 

 gree to which different woods are termite-proof and the basis 

 of their immunity. Only two woods were found to be entirely 

 resistant, namely, the Australian cypress pine, Callitris glaucn, 

 and the Indian teak, Tectona grandis. Some Philippine woods 



G Oshima Phil. Jn. 8c-i. XV (4), 1919. 



