40 NATURAL HISTORY OF GLOSSINA PALPALIS 



out of a large number caught on a given day only a few 

 would contain fresh blood, and in these cases a proportion 

 would be mammalian blood. In the other cases many 

 would be merely recognizable as nucleated non-mammalian 

 blood, and in only a very small proportion would the 

 corpuscles be sufficiently unaltered to allow of measure- 

 ments being taken. 



During this work note was taken of the presence or 

 absence of Trypanosomes in the gut of the fly, and in the 

 proboscis. Certain Trypanosomes (e.g. T. vivax, which 

 kills goats very quickly) only develop in part of the 

 proboscis and are not found in the gut ; but others, such 

 as gambiense, may be found in both. 



Of 600 flies examined at Jinja, 11 per cent, contained 

 Trypanosomes in the gut ; of 695 on Damba, 34 per 

 cent, had Trypanosomes ; and on Bugalla 1,000 flies 

 showed Trypanosomes in the gut in 1*7 per cent, of the 

 total. Out of 638 cases in which the proboscis was 

 examined on Bugalla, 14 had Trypanosomes in the 

 proboscis alone ; i.e. 2*2 per cent, of the wild flies appear 

 to be infected with Trypanosoma vivax. ^ 



It must not be supposed that all the Trypanosomes 

 found in wild flies are gambiense : some are devived from 

 the crocodile {T. grayi), and so far as is known are harm- 

 less. 



Besides Trypanosomes bacilli are often found in count- 

 less numbers in the gut of the fly, but in a different part. 

 Nevertheless there appears to be some inverse relation 

 between the two, for out of six hundred flies at Jinja, 

 in only 3' 4 per cent, of flies containing bacilli were 

 Trypanosomes also found, and in only 61 per cent, of 

 flies containing Trypanosomes were bacilli found. 

 Bacilli were present in 19-3 per cent, and Trypanosomes 



^ Dr. Duke has shown that the Situtunga is a natural host of T. vivax 

 as well as of T. gambiense. ReiJort No. XII of the Sleeping Sickness 

 Commission, p. 122. 



