TERMITE TRUFFLES. 209 



in which chimneys open into a great central dome chamber. In 

 the case of the form investigated by me in Ceylon I found the 

 chimneys communicating directly with the fungus chambers, 

 although the design is generally such that rain cannot directly 

 reach the fungus-cultures. Whether there is any arrangement 

 for the disposal of water I was unable to ascertain. 



In conclusion, I should like to discuss one point briefly. It is 

 a remarkable fact that we find the cultivation of fungi practised 

 by ants and termites : that is to say, by the two orders of social 

 insects which are farthest removed from one another in point of 

 affinity. How is such a wonderful convergence to be explained ? 

 In the history of the social insects there are many phenomena 

 whose first appearance will always remain inexplicable. More 

 interesting and important is the question whether we can in any 

 way conceive and analyse the phenomenon. At first sight the 

 convergence as between Termites and Ants is quite wonderful 

 and could lead to the rashest hypotheses, like the convergence 

 between the ant species Oecoplnjlla smaragdina and Camjmnotus 

 senex, both of which use their larvas as spinning machines in 

 weaving their nests. Is their any means of tracing the causal 

 relations in the origin of the fungus cultures of the Termites and 

 eventually of investigating them experimentally ? 



I think that the biology of Termites gives us points which will 

 support a hypothesis, and I very much regret that the thought 

 did not occur to me while I was in Ceylon so that I might under- 

 take the not very difficult testing of its principles. My suspicion 

 is that the f augus which grows in the fungus cakes is a common 

 fungus occurring in rotten wood in the neighbourhood, and that 

 it is conveyed with the chewed wood quite unconsciously by the 

 insects into the nest. The fact that it grows there almost 

 in pure culture could be explained by supposing that the wood- 

 brew is partially sterilized by the action of the saliva or gastric 

 juice, so that the chewed wood becomes a medium for the 

 exclusive growth of the particular fungus, all others being 

 suppressed. Thus the structures automatically become fungus 

 gardens (although, as in many other cases, originally intended 

 only as passages and resting places for the larvae, &c.), which are 

 then methodically utilized by the Termites. It is not excluded 

 from possibility that the inhabitants acquire a weeding habit, as 

 MoUer assumes for the species of Atta. 



Such an explanation still leaves riddles to be answered in con- 

 nection with the cultivation of fungi by Termites ; but perhaps 

 it helps to elucidate part of the problem and points to the 

 solid ground of natural law. 



