RIVER, EAST AFRICA PROTECTORATE. 273 



The Masai showed me all the areas where they knew from experience tsetse- 

 fly existed. These arc shown on the accompanying sketch-map, but there are 

 probably more streams than are indicated on the map. After discussing' the 

 subject carefully with the local Masai, I came to the conclusion that, although 

 they only knew tsetse-fly to exist on some of the small water-courses coming 

 down from the escarpment and on the Amala river, they nevertheless wisely 

 treated all these small water-courses with suspicion, except in the case of sheep 

 and goats, and only approached them with their cattle if compelled to do so for 

 want of water. They told me that tsetse-fly was to be found all down the Amala 

 river from this point into German territory, and that although it was far more 

 numerous during the rains it was always present all the year round. Some of 

 the Masai insisted that the fly only existed on the west bank of the river, others 

 said it was to be found on both banks. This is a very interesting point in view 

 of the fact that two previous attempts to find this tsetse-fly on the Amala 

 had failed, and also because the phenomenon of tsetse-fly existing on one bank of 

 a river and not on the other has been reported from other parts of Africa. 



In October 1912, I visited this portion of the Amala for the first time, and 

 travelled down the east bank as far as the bend in the river where " Judd's old 

 store " is shown on the map. Knowing that tsetse-fly were said to exist here 1 

 searched carefully all down the east bank of the river from the Government post 

 to the lower store. I failed to find any trace of Glossina, and six mules, a pony 

 and two dogs which I took with me all down the edge of the river were not 

 infected and are still alive and well. I did not cross to the west side of the river. 

 Both my visits to the Amala were made during the dry season (which extends 

 from about the middle of June or end of May till November or December, or 

 in bad years till March), and on the west bank tsetse-fly in small numbers were 

 discovered, while on the east bank none could be found. Of course it is quite 

 possible that owing to the dry season and there being few flies about, tsetse may 

 have been on the east bank of the river without being detected on the occasion 

 of my first visit ; but there is other evidence which makes this unlikely. 



In May 1913, during the rainy season, Mr. T. J. Anderson, Government 

 Entomologist, visited the Amala river with the object of investigating the 

 reported presence of Glossina. He approached the river from the east, and 

 followed that bank from near the Anglo-German border up to the Government 

 post above Judd's store. He found no signs of tsetse-fly at any part of the 

 Amala which he visited, and I attribute this to the fact that he was unable to 

 cross to the west bank owing to the river being in high flood. Mr. Anderson's 

 visit was made at a season when tsetse-fly should have been numerous and in 

 evidence if they exist on the east bank of the river. 



Further than this, there is the evidence to be drawn from the case of the store- 

 keeper Judd, who had a trading station at the bend of the river marked on the 

 map. He occupied and used this store for 18 months, dealing in sheep, goats 

 and cattle from the natives, and also had mules- and ponies from time to time at 

 the store. 



In March 1911, during the rains, two mules and four horses were kept at the 

 lower store, and were used on both sides of the river hunting lions for 15 days. 

 None of these animals died. 



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