of Edinburgh, Session 1884-85. 
141 
for they take not the slightest notice either of the workers or the 
works. They are posted there in fact as sentries, and there they 
stand, or promenade about, at the mouth of every tunnel, to keep at 
bay the warlike hordes of Formicidce — the real ants — who forage 
about in every tropical forest in unnumbered legions. To every 
hundred workers in a white ant colony, which numbers many 
thousands of individuals, there are perhaps two of these fighting- 
men. The division of labour here is very wonderful, and the fact 
that besides these two specialised forms there are in every nest two 
other kinds of the same insect, the kings and queens, shows the 
remarkable height to which civilisation in these communities has 
attained. 
Now where is this tunnel going to, and what object have the 
insects in view in ascending this lofty tree? Thirty feet from the 
ground, across innumerable forks, at the end of a long branch are a 
few feet of dead wood. How the ants know it is there, how they 
know its sap has dried up, and that it is now fit for the termites’ 
food, is a mystery. Possibly they do not know, and are only pros- 
pecting on the chance. The fact that they sometimes make straight 
for the decaying limb argues in these instances a kind of definite 
instinct ; but, on the other hand, the fact that in most cases the 
whole tree, in every branch and limb, is covered with termite 
tunnels, would show perhaps that they work most commonly on 
speculation, while the number of abandoned tunnels, ending on a 
sound branch in a cul-de-sac, proves how often they must suffer the 
usual disappointments of adventurers. 
The extent to which these insects carry on their tunnelling is 
quite incredible until one has seen it in nature with his own eyes. 
The tunnels are perhaps about the thickness of a small-sized gas- 
pipe, but there are junctions here and there of large dimensions, and 
occasionally patches of earth-work are found embracing nearly the 
whole trunk for some feet. The outside of these tunnels, which 
are never quite straight, but wander irregularly along stem and 
branch, resembles in texture a coarse sand-paper; and the colour, 
although this naturally varies with the soil, is usually a reddish- 
brown. The quantity of earth and mud plastered over a single tree 
is often enormous ; and when one thinks that it is not only an 
isolated specimen here and there that is frescoed in this way, but 
