32 
Bulletin ofthe EANHS 27(2>3) 
a small parly in two 4WD vehicles. The track 10 the lake 
is faint, and very rocky. The campsite is flat. with line 
views, but there is no shade and no water. 
Little Magodi. also known as Lake Nasikie Engida 
( I °43 ’ S: 36“1 V E altitude 627 m). is a small lake on the 
Figure 1 Map ot Lake Magad < and Little Magadi or 
Lake Nasikie Engida 
NW side of Lake Magadi (figure I >. rhe water level is 
19 m higher than the main lake (Baker. I 5 8 » Water 
enters the lake at its NW comer from hut springs that 
rise at the foot of East-facing cliffs. The springs rise 
at many different points and discharge into shallow 
streams flowing over a braided bed of sand and gravel 
down into the lake. 
luxuriantly. In flowing water it was attached to the 
bottom and floated downstream. In pools it formed dense 
mats producing copious gas bubbles in sunlight. Where 
it was killed by excess heat it became bleached white. 
At 44° C and below it was gradually replaced by a 
yellowish-green encrusting alga Chloro/lexus sp.. which 
became dominant at about 38° C. When damaged or 
dead it became orange or bright red, or sometimes black 
and smelly. 
In still water at temperatures between 37 n and 59° C 
a small brine fly (family Ephydiiilue) swiumcd un the 
surface, and its larvoe and pupae lived in the filamentous 
mat. Between 44® and 50° C this was the only animal 
found, but at lower temperatures it overlapped with a 
large black brine fly Ephvdru mu^mJensis. Vast numbers 
of adults of the latter swarmed on the surface of water 
at temperatures between 35° and 38° C. The flies lay 
salmon-pink eggs that hatch into silvery-grey larvae. 
The pupae are blackish with thick, leather) skin, and 
have two curved processes on the back by which they 
anchor themselves. The young stages ore in constant 
danger of straying, or being carried by the flow, into 
water that is too hoc, which results in deposits of dead 
larvae and pupae stranded on sand banks Probably 
the juveniles arc also eaten by the many wading birds 
iirtrnrfrd In thr 
In samples from temperatures up to 38° C I found 
larvae and pupae of a fly of the family Ceratopogonidae. 
Up to 34“ C there were also red larvae of a fly 
Chironomus sp. (family Chironomidae) living in slime 
lubes. In pools at about 32" C I found water beetles of 
the family Hydrophilidae, and many small copcpods 
Cleiocampius conjlucn* (Schmei!) of the family 
Clctodidnc (Crustacea). 
Long-legged spiders with bodies about half a 
centimetre long ran very fast over exposed sand and 
gravel, and also seize larvae and pupae at the water 
surface. A smaller, reddish spider hunted in similar 
fashion but remained on dry land. 
In 1 984 many dead insects were seen in the springs, 
including grasshoppers, a dragonfly, a bug Lethoceros 
nlloiicus (family Bellostomatidac). water beetles 
Cy bister sp. (family Dytiscidae) and many large 
caterpillars of moths ( family Sphingidac). Large numbers 
of anal I fish Tllapiagrahami were seen in cooler water. 
None of these were seen on the second visit in 1 997. 
Ephydra magddensix was described (Wirth. 1 975) 
from samples collected at Lake Magadi. and it is not 
known to occur at any other site. The flies swarm on 
mud in lagoons around the (dry) main lake The small 
ephydrid fly is a new species, and is about to be 
described. The ccratopogonid fly, the chironomid fly, 
the hydrophilid beetle and the copcpod have not yet 
been identified 
Temperatures measured directly in the spring 
outflow’s were between 70" and 82° C. In the streams the 
water temperature varied over short distances 
depending mainly on the flow. 
At temperatures up to 50-55° C the filamentous blue- 
green “alga" Arthrospira platensis (Cyanophyta) grew 
.Acknowledgements 
The cyanophytes. algae and bacteria collected from the 
springs were kindly identified by Dr Mwatha of the 
Botany Department, Kenyatta University. Professor J. 
Green identified the copepods. 
