TSETSE-FLIES OF THE KABALO-ALBERTVILLE RAILWAY. 173 



And how can we explain by the game theory the diminution in morsitans along the 

 third section, in the valley of the Lukuga ? At first glance the explanation seems very 

 simple and easy. :; The construction and exploitation of the railway (and the passage 

 of troops) have produced a great diminution in the game, and that is the cause of the 

 diminution of morsitans" Very well. But on the other hand there exists now a 

 continual coming and going of men along the railway (instead of very few natives as 

 in former times), and are not men from the point of view of morsitans game, like any 

 other animals ? Is not the diminution of morsitans rather due to the artificial clearing 

 of the banks of the railway and of the thinning of trees in its vicinity ? The clearing 

 along the railway by force of circumstances will continue, and in the near or distant 

 future we may expect a large track denuded on each side of the route, which will be 

 followed by a notable diminution in tsetse, and even eventually by their more or less 

 complete disappearance, according to whether the denuded track is wide or narrow. 

 However, this is only theory. In reality there will probably be several series of 

 artificial clearings, that is to say bare tracks alternating with wooded stretches, which 

 obviously will not cause the disappearance of Glossina throughout the length of the 

 railway. It rests, therefore, with the Directors of the Railway not to lose sight of 

 the question of the tsetse and to organise their clearings accordingly. 



Kabinda, December, 1916. 



