370 CLAUDE FULLER. 



had penetrated the mound at that point. The mound on tlie 

 whole displayed a weathered appearance, but the surface had 

 been recently repaired immediately above the cavity, whilst 

 parts of the cone had had some attention. 



Inferentially we may assume that it is possible for nests of , 

 this species to exist without mounds; but as to whether there 

 is any reason to suppose that under certain climatic condi- 

 tions — such as along the Witwatersrand (5000 ft.) — the 

 species never makes a mound, the writer is not yet prepared 

 to make a statement. In this connection it may be men- 

 tioned that the species has been taken destroying young- 

 gum-trees (Eucalyptus) and feeding upon manure where 

 no indication of a mound could be seen for a mile around. 

 Again the species has been seen feeding upon grass in 

 Pretoria where no mound could be found. This latter instance, 

 however, rather indicated the existence of a colony that had 

 not as yet built a mound than one that would never do so. 



It is not .yet possible to say for certain how a nest of 

 natal en sis as an architectural structure begins; but it is 

 not difficult to see how it could originate by observing the 

 behaviour of young pairs, and their peculiar adaptability to 

 their environment in nests built under houses, or in the 

 earth-matrix filled in beneath cemented, bricked, or stone- 

 flagged floors. When nesting beneath such floors natal- 

 ensis does not need to build a protecting mound. As a rule, 

 however, there are dump-heaps ; these may be either in free 

 spaces beneath the house or even outside of it (PI. XXYI, 

 fig. 18). 



A number of such cases have come under observation, and 

 the nests arise out of the entrance of a pair through some 

 interstice. In the case chosen for illustration, the queen-cell 

 was just below the cement, and tlie hive extensions were 

 below it ; the nest arrangement is inverted, the cavity being- 

 extended downwards instead of upwards. 



What appears to be the ordinary course of events is for the 

 sexual couple to burrow into the soil to a certain depth ; this 

 is about 18 to 20 in. There thev form their brood-cell. When 



