CONSTITUTION AND DEVELOPMENT OF TERMITES. 259 
together pieces of wood which are unduly loose; but at other 
times they do not do so, although much incommoded by their 
mobility. In certain cases they line the lumen of the tube 
with disgorged matter, so as to form a continuous layer, save 
for a few irregular patches, but they generally spare them- 
selves this task, or merely begin and immediately abandon it. 
It should be added that if the tube is too damp its inner 
surface may be covered with moisture, to which the insects 
adhere, particularly when young, and so die. This is guarded 
against, at least partially, by the lining of disgorged substance. 
When the supply of wood in the tube is very small, the 
Calotermites usually have recourse to the cork, in which they 
bore one or more galleries a little wider than their body ; they 
gnaw away and hollow out the cork, carrying the débris into 
the tube, which is soon filled up, as the cork-dust is allowed 
to remain as a loose mass. 
If a corked tube is surrounded with sawdust, some of it can 
generally be found in its interior, having been carried in 
through galleries in the cork but little wider than the insects’ 
bodies. 
[The corks of tubes kept in the waistcoat pocket are often 
channelled with burrows leading to the exterior, through which 
the insects escape and are lost, in the belief that they are 
enlarging their nest. Sometimes books near which the waist- 
coat was laid at night were attacked, and the paper was found 
to be gnawed in places the next morning. | 
Burrows made in corks may often be seen to possess a sort 
of rounded lid at their external opening; this is cut out of the 
superficial layer of cork, and fits tolerably closely, though it 
usually falls in a little. It may be hinged to the cork by a 
more or less wide attachment. 
[Calotermites may be frequently seen to carry excrement to 
the bottom of the tube, and to accumulate it there, mixed 
up with wood and cork-dust ; and sometimes they keep the eggs 
in the same place. | 
If the stopper is too narrow the space between it and the 
tube is gradually filled up with excrement. 
