482 



destroyed by ants in such a situation as compared with a light 

 soil is probably far more than compensated for by the quicker 

 and more luxuriant growth of the trees that escape. 



X. — Spacing. 



The distance between the trees is also a decided factor in 

 their liability to attack, the wider the spacing the smaller being 

 the proportionate number of trees lost. This is no doubt due to 

 the desiccation of the trunks and surface soil by the sun's rays 

 This slight advantage seems to be far more than counterbalanced 

 by the much smaller return per acre and the slower growth of 

 the trees when widely planted. 



XI. — Influence of Season. 



White ants are much more active during periods of heavy 

 rain, or rather immediately after such rain. 



XII. — Method of Attack. 



The methods of attack of T. gestroi are eminently characteris- 

 tic, and when once their earthworks are seen and recognised, 

 they can never be mistaken for those of any other species. The 

 tree seems first of all to be prospected, by two or three tunnels 

 run straight up the trunk ; if the indications are favourable the 

 whole circumference is then rapidly invested by a thick layer of 

 mud, under cover of which the ants speedily eat down to the 

 cambium. The vast majority of attacks by individual termites 

 are repelled by the cambium, but sooner or later a non-resistant 

 spot is reached and the whole body of termites gains access to the 

 interior of the tree, which is rapidly eaten out and falls. In a 

 very considerable percentage of cases, there are no external signs 

 of damage, and the insects enter the tree either by a lateral root 

 from a point beneath the surface of the soil, or by way of the 

 taproot itself. In such cases the tree may appear perfectly sound, 

 until it falls or is blown over. Damage is caused not so much 

 by the actual death of the tree, for in many cases the living tissues 

 are perfectly sound, but from the weakening of the trunk and 

 taproot added to the natural brittleness of the wood, rendering 

 them unable to resist the slightest wind pressure. On certain 

 estates it has been noted, that where tapping has been somewhat 

 roughly performed, and the cambium extensively cut into, white 

 ants have gained access through the scars thus produced. It is 

 therefore highly important that the cuts should be made down to 

 but not into the cambium layer, as is the case on the Sungei 

 Rengam Estates, where in no single instance have ants secured 

 a foothold in the manner indicated above. 



XIII. — General Bionomics of Tekmes Gestroi. 



I have not been successful, nor, so far as I am aware, has 

 any other naturalist, in finding the king and queen of Termcs 

 gestroi. Amongst numerous communities investigated one was 



