118 .T, S. HAMILTON — THE RELATION BETWEEN GAME AND TSETSE-FLIES, 



The temperature at that time of year (July and August) varied between a 

 maximum of 85° Fahr. b}' day, and a minimum of oO° Fahr. by night. There 

 was no rain. The soil showed a fairly constant formation of metamorphic granite 

 rock, traversed by quartz reefs ; there were no apparent indications of clay, slate, 

 or limestone. The surface of the ground was generally covered with granite 

 sand. The mean altitude of the plateau where the fly was found was about 

 1,500 feet. Judging from the vegetation, I should think there was a fair, though 

 not an excessive, rainfall in the wet season. 



As soon as we crossed the Lujenda, a wide and deep river, we got quite out of 

 touch with the fly. The land gradually rose from 1,800 to about 2,500 feet at 

 the base of the Nyasa Mountains. This piece of country was very much better 

 watered than the dry plateau between the Msalu and Lujenda Rivers, and there 

 wei'e traces (albeit scanty ones) of buffalo, elephant and hartebeest. Up to 3,000 

 feet there seemed little change either in the vegetation or in the nature of the 

 soil, but Glossina wei-e entirely absent, so far as we were able to judge, along our 

 route west of the Lujenda. 



Although it would be rash to express any dogmatic opinion concerning so 

 complicated a matter as the relation between tsetse-fly and game from the 

 experiences of a journey embracing only one period of the year, I feel fairly 

 convinced that within the above area the fly, G. morsitans, exists to a great 

 extent independently of the blood of large quadrupeds. I am further induced 

 to believe in the general absence of the latter from the fact that from first to 

 last I did not see a grass tick of~any kind. These insects are, I think, nearly 

 always found in tropical countries, where many large mammals wild or tame exist, 

 and moreover, being able to live for many months without blood, are independent 

 of occasional temporary migrations of wild animals from their vicinity. It was 

 of course winter, but the temperature during our journey was never so low as to 

 have impaired their vitality had they been present. 



Koniati Poort, March, 1911. 



