196 DR. JAMES J. SIMPSON. 



Relation to Game. — Lloyd has drawn attention to the fact that where game is 

 plentiful 13 per cent, of female G. morsitans were caught, whereas where game was not 

 plentiful 41 '5 per cent, of females were taken. This relationship is confirmed by my 

 observations in West Africa. At Larabanga game is extremely abundant, and during 

 22 days' collecting in July and August the percentage of females was 9 '2. At Murugu, 

 on the other hand, where native hunters are numerous and game consequently scarce, 

 the percentage in June was 54, while in August it was 15. Lloyd also remarks that 

 when game is plentiful the number of pupae taken daily was 31, whereas where game 

 is not plentiful the number was only 7. This is also borne out in West Africa. These 

 two facts, contradictory as they may seem, are yet easily accounted for, and are what 

 one would expect. Where game is abundant the females manage to feed easily, and 

 when fully gorged retire to the seclusion of some shady place, consequently the number 

 of females seen and caught is diminished. Following on this is the fact that if the 

 females feed easily they propagate more rapidly, consequently the number of pupae is 

 increased. 



All over the Northern Territories the close association between G. submorsitans 

 and game is very marked. Wherever game is abundant, there tsetse will be in like 

 proportion. I have elsewhere remarked on the fact that my attention has frequently 

 been drawn to the presence of game by observing an increase in the number of tsetses. 

 The table showing the proportion of the sexes in G. submorsitans will bear out this 

 association, e.g., at Larabanga, where game is plentiful, the average daily number of 

 G. submorsitans taken was over 100, whereas at Murugu (between Larabanga and 

 Daboya) where game is kept under by native hunters the daily average was about 50. 

 The nature of the fauna and its association with tsetse has often been commented 

 upon, but in West Africa I have never seen any marked disparity in the number of 

 G. submorsitans associated with buffalo or warthog, although I have followed and shot 

 practically every species of game in the country. I have elsewhere remarked on the 

 close association between G. submorsitans and the dog-faced baboon (Papio sphinx), 

 and this fact was again brought to my notice during my past tour. At one camp 

 where my collectors brought back very few tsetse, I naturally enquired the reason, 

 and they explained that there were no monkeys. Now as my carriers that day 

 caught a small monkey I pointed this fact out to them, but they explained that it was 

 not the small monkeys they meant, but the dog-faced baboons. They also said that 

 where the baboons were abundant tsetse were also abundant. This fact is difficult 

 of explanation, as it is highly improbable that tsetse feed on these animals, yet if such 

 an association be established, the question of exterminating tsetse by the destruction 

 of game becomes exceedingly more difficult. 



Meteorological Conditions. — I have elsewhere discussed this question in extenso, 

 but would point out that humidity is the prevailing factor influencing the numbers 

 of tsetse. At the beginning of the dry season these insects increase greatly in numbers. 

 Whereas actual sunshine only affects the daily period of activity, a hot sun most 

 strongly affects G. palpalis, which seldom follows one in direct sunshine. G. tachi- 

 noides is next affected, whereas G. submorsitans will follow and attack in the open in 

 the hottest sun, but seldom at night. Roubaud states that G. morsitans when exposed 

 to a temperature of 40° C. (104° F.) died within an hour. This I did not find to be 

 the case in the Northern Territories. I have frequently caught them in the open at 



