202 



DR. JAMES J. SIMPSON. 



Again, take the case of Gnani and Danio in Togoland. These places are practically 

 identical in every way, yet at the former three days' collecting resulted in the 

 following — 127 males and 194 females ; while at the latter the position was reversed, 

 and 126 males were caught to 114 females. 



On the River Lora between Larabanga and Daboya, in April 1916, the proportion 

 of males and females was as 51 '5 to 48*5 ; rainfall 4'77. This river satisfies two of 

 the conditions insisted on by McConnell and Bequaert. It is a small tributary of the 

 Volta, and it is several hours from the nearest village, consequently uninhabited. 

 Yet in the case of G. tachinoides, if we may judge from the results here found, neither 

 of these factors has any bearing on the proportion of the sexes. But it is only right 

 to point out that these authors were dealing with G. palpalis. 



At Zantana (N. of Daboya) in the same month, April, the relation was 57 per cent, 

 males and 43 per cent, females. This village is also on a small tributary of the Volta, 

 but the difference in percentages of the sexes is not appreciable. 



At Gwa, a small village S.E. from Daboya far removed from the River Volta, in 

 March 1916 the proportion was as 62 to 38 per cent. 



At Kito, a similar locality, a little further south in the same month the proportion 

 was as 65 to 35 per cent. 



The one outstanding feature which these figures exhibit is that the percentage of 

 males decreases as the rains gain in intensity and the humidity increases. (Compare 

 this with G. submorsitans). 



Now let us consider the case of G. submorsitans, and see how far the proportion of 

 sexes is in accordance with the figures found for G. tachinoides. The following table 

 has been prepared for various localities in the Northern Territories at different 

 seasons. 



It will be seen that Larabanga was visited at four different periods in July and 

 August, but that the percentages are practically the same. In the case of Murugu 

 and Kapoto (some miles S.W. from Daboya) the difference between June and August 

 requires some explanation. 



Larabanga 



Kabampwi 

 Guripe 



>> 

 Murugu 



a 



Yarizori 

 Kapoto 



>> 

 Kofaba 

 Larabanga Bush Camp I. 

 Larabanga Bush Camp II. 

 Larabanga Bush Camp III. 



Percentage. 



1-7. vii.16 



721 



100 ) 







14-18. vii.16 

 25-28. vii.16 



546 

 202 



* 



90-8 



9 2 



15-21. viii. 16 



816 



78 J 







29. vii.16 



52 



4 



90-7 



93 



30.vii-3.viii.16 



300 



33 \ 



6 1 



91 



9 



11-14. viii. 16 



69 



31. vi.16 



25 



29 



46 



54 



21. viii. 16 



46 



8 



85 



15 



22. viii. 16 



58 



4 



91-5 



8-5 



28. vi.16 



80 



52 



60 



40 



23. viii. 16 



109 



5 



93 



7 



4-9. ii.16 



261 



76 



445 



55'5 



14-20. vi.16 



660 



38 



94-5 



.._5-5 



23,24. v.16 



268 



14 



95 



5 



8-13. vii.16 



336 



36 



91 



9 



