92 



Trypanosome Diseases of Domestic Animals in Nyasaland. 

 Trypanosoma capree (Kleine). Part III. — Development in 

 Glossina morsitans. 



By Surgeon-General Sir David Bruce, C.B., F.R.S., A.M.S. ; Major A. E. 

 Hamerton, D.S.O., and Captain D. P. Watson, B.A.M.C. ; and Lady 

 Bruce, R.R.C. (Scientific Commission of the Royal Society, Nyasaland, 

 1912-14.) 



(Received April 7, — Read June 18, 1914.) 

 [Plate 8.] 



Introduction. 



In a previous paper* the morphology and action on animals of this species 

 of trypanosome were described. In this is given an account of its develop- 

 ment in Glossina morsitans. 



Trypanosoma caprce belongs to the T. vivax group, in which the develop- 

 ment of the trypanosomes is restricted to the proboscis. 



The Development of T. Caprje in G-. morsitans. 

 Six experiments were made with laboratory-bred flies. Five were positive 



and one negative. 



Table I. — Laboratory-bred Flies. 



Date. 



Expt. 



No. of 

 flies 

 used. 



Experiment 

 positive or 

 negative. 



No. of infected 

 flies found. 



No. of days 

 before flies 

 became infective. 



Mean 

 temperature. 



1912. 















April 16 



444 



12 



+ 



1 



16 



71° F. (22-1° C.) 



June 3 



617 



33 











65° F. (183° C.) 



3 



1215 



22 



+ 



1 



21 



65° F. (18-3° 0.) 



1913. 















Jan. 18 



1777 



35 



+ 



11 



19 



84° F. (28-8° C.) 



„ 22 



1784 



35 



+ 



20 



19 



84° F. (28'8°C.) 



April 1 



2046 



33 



+ 



13 



20 



84° F. (28-8° C.) 



One hundred and seventy laboratory-bred flies were used and forty-six 

 infected flies were found — 27'1 per cent. The first three experiments were 

 carried out at the ordinary temperature of the laboratory ; in the last three 

 the cages containing the flies were kept in an incubator. It is difficult to 

 understand the difference in the number of infected flies found. In 

 Experiments 444 and 1215 only 8 and 5 per cent, respectively of the flies 

 became infected, whereas in the last three experiments, an average of more 

 than 40 per cent, was found. The flies in the second group were kept, it is 

 * ' Eoy. Soc. Proc.,' B, vol. 86, p. 278 (1913). 



