70 
types of country, and as the tsetse is also shown capable of selective 
powers, may it not be that the association of fly —used without 
distinction of species — and particular varieties of pame is but a 
natural inclination of both beings to the same locality, and not 2 
peculiar affinity between the individuals? 
These statements do not answer why the tsetse (believed to have 
been both Gl. morsitans and its relative Gi. pallidipn) has 
disappeared from parts of Africa South of the Zambesi, but they go 
to show that game destruction by civilisation and rinderpest is not the 
only factor concerned Until we are better acquainted with the 
lonomics of the genus Glossina, by observation and experiment 
conducted on scientific lines, the statement “ that certain species of 
setse exist only where wild game exists" must remain controv'ersial, 
ut with a bias to the negative, if. indeed, it must not be negatived 
j 1, ^ second of your correspondent’s propositions may be 
dealt W.th .n a mere dogmatic fashion. •' - that certain gLns 
'vhich produce in 
the tse'ts H'r^ne germs wlien transferred by 
e tsetse . . are the cause of Ngana or tsetse fly disease." 
common w^tirthTsTof ZU “untries all possess features in 
incapable of li - j* 'vhich was shown by Bruce to be 
biting fly to hT*" 7 be spread by a 
cnly ln mmor S rucT r ^hey dir 
^tock. pr; a7 deT ■" ‘heir actions upon 
towards some trynanos ' result in a susceptible animal, but 
degree of r^LtTnoe “r"' ^ 
game towards the Zulu'lan7forI!f '"’'"‘"'"K ‘bat enjoyed by wild 
deri'vt: 
may not suffer from the disease ’ like big game 
showed that buffalo koodon -u’ animal already sick. Bruce 
be that reservoir n Natal n r and hyaena may 
beck in the Congo Free 7 ^bat the bush- 
disease there; and in North W ‘he trypanosome of fly 
germ m bush-buck and Lichten 7 T ^bodesia we have found the 
‘be same as that fold b^B ^his germ is not 
identical. In North-Western sickness in cattle is 
stern Rhodesia, and when properly studied 
