NOTES ON THE BIONOMICS OF GLOSSINA MORSITANS. 



127 



It is not claimed that the only way in which one or two abnormally heavy wet 

 seasons could affect the tsetse-fly lies in inducing a wider distribution of water and 

 attractive grazing during the dry season. The involved interrelationship between 

 the tsetse fly, its diseases and enemies, the enemies of its enemies, and so on, is 

 almost a closed book at present, and this interrelationship is no doubt affected in 

 some degree by the season. It is only intended to point out a possible explanation 

 of the observed phenomenon as a basis for future research. The abnormally heavy 

 rains of the past wet season have certainly affected the appearance of some parts 

 of the country in the dry season to a marked degree, and the fly has undoubtedly 

 decreased in certain areas, one of which at least, as the writer has endeavoured to 

 show, has also been affected by the increased rainfall. 



Curiosity naturally suggested reference to the records of rainfall in the territory 



with a view to ascertaining whether any record of one or two seasons of exceptional 



severity preceded any definite information concerning reduction of fly. The 



available rainfall statistics unfortunately date no further back than 1888 and in the 



(687) o 



