OBSERVATIONS uN SOME SOUTH AFKICAX TERMITES. 6^^ 



to a depth of 6 to 8 in., the diameter of the subterranean 

 part being invariably greater than that of the base of the 

 mound. All the cells are of about one dimension except for 

 one, or perhaps two, central cells, which lie two inches below 

 soil-level. Tiiese are wide and shallow, and are the head- 

 quarters of queen and king. The rest of the cells are very 

 irregular, but tend to become flattened spheres ; each foi-ms a 

 separate compartment communicating with adjoining com- 

 partments by two or three small perforations in the walls. 

 The walls between the cells may be described as strong, and 

 of a fairly uniform thickness. The perforations have a small 

 diameter of 2 mm., and are counter-sunk into each wall. 

 There is no series of large permanent galleries leaving the 

 nest, and such galleries as do lead away are fine and not 

 easily traced. In the large series of nests (both normal and 

 abnormal) examined nothing in the nature of stored pro- 

 visions has been met with. Upon the other hand, the 

 multitude of workers, always present, invariably have their 

 abdomens so grossly distended that they can only be looked 

 upon as animated food-reservoirs. 



When observations were first begun upon this species the 

 frequent intermingling of its mounds with those of E. triner- 

 vius, and a general resemblance in the relation of the mound 

 to the subterranean part together with other broad structural 

 features, led to a suspicion that bilobatus invaded small 

 deserted nests of trinervius, as indicated by Haviland, and 

 converted them into a structure to their own liking. Then 

 the discovery of a small mound inhabited in part by the two 

 species, one half built to the bilobatus pattern, the other to 

 that of trinervius, led to a series of observations which 

 showed that bilobatus simply expels young trinervius 

 colonies from their own mounds. The process is nut, so far 

 as can be seen, one of decimation : bilobatus simply gaining 

 an access to one point of the trinervius mound, and then by 

 gradually converting the more open trinervius galleries 

 into cells, it slowly builds the original artificers out. This 

 process often results in the building of a new mound some 



