OBSERVATIONS ON SOME SOUTH AFRICAN TERMITES. 



879 



cliaracter after years of occupation by successive colonies of 

 this and perhaps other termites. The thickets in Pretoria are 

 composed of several varieties of acacias (Acacia horrida, 

 robusta, and caffra predoniinating"), associated with them 

 are other thorny plants, the more usual kinds being 

 G3Mn nosporia buxifolia, Ehretia hottentottica, and 

 the spiny Asparagus. In these mounds, which may reach 

 2 ft. above ground-level and be 10 to 20 ft. across, the 

 actual nest is above soil-level ; but the whole is generally so 

 involved by the intermingling and twisted root-systems as to 

 render any account of the interior structure impossible. 



Text-fig. 10. 



T. bad ins. Vertical section of nest in mound, involved in root- 

 systems of many plants (diagrammatic), (x J^j.) 



In one instance, however, where a thicket had been burned 

 over, the nest-cavity was found baked and preserved, the 

 clay composing it being changed into a fairly hard red tile. 



In the case of the modern nests the structure is readily 

 observed, and, whilst erratic, keeps to a general plan. The 

 external feature is the presence of the series of hillocks 

 already referred to. In some cases these are superimposed 

 upon the mat of leaf-debris under the trees; when this is the 

 case they can be lifted bodily from the ground. They are not 

 solid, but are perforated by small tubular, twisting galleries 

 which lead from the centre at the base and allow the termites 

 to dispose of excavated earth by placing it as a new crust to 

 the moundlet. 



The tenuous galleries all enter at ground level into a fairly 

 large gallery or vertical shaft, which descends either by a 



VOL. 3, PART 2, 26 



