XIV 
ON SAFARI 
177 
to Lake Nakuru, the grass over a large part of the 
country liad been set on fire, and in many directions it 
was burning briskly. In the districts traversed by our 
porters several elliptical areas of plain soil among the 
blackened grass attracted my attention. These patches 
measured in most instances three yards in the major 
and two in the minor axis : they were sunk slightly 
below the level of the surrounding ground and were as 
free from grass as a newly-polished tombstone, and the 
surface was as smooth as if it had -been finished by a 
plasterer s trowel. In the first instance I was interested 
in these smooth patches because on many of them we 
found game tracks, such as footprints of the impalla, 
water-buck, hartebeest (kongoni), or the rhinoceros. 
These footprints stood out as plainly as the imprints of 
a hare, polecat, or rat on snow-covered ground. 
On examining the bare patches more carefully, I 
found two or three circular holes surrounded by a ridge 
of dust, an inch high, from which brown ants issued ; 
near the edge of the patch there was a heap of husks, 
and on examining them they proved to be the husks of 
many varieties of grass seeds. When the patch was 
situated in an area where the grass had been closely 
burnt it was easy to make out ant-paths radiating 
in many directions from the clear area, and the ants 
laden with seed could be seen travellino; alonsf them. I 
have re-read carefully Moggridge’s description of 
harvesting-ants ; I have no doubt that these elliptical 
patches of grass-free ground are due to the energy of 
some species of these interesting and industrious insects. 
The smooth appearance of the patch is due to the 
persistent traffic of multitudes of these small insects. 
It is curious that the grass and other seeds in these 
underground granaries do not germinate. No satis¬ 
factory explanation has yet been advanced to account 
for this fact, and I have no theory to offer. These 
elliptical ant-grounds were numerous in the grass land 
around Lake Nakuru. They were clear of small stones, 
N 
