BV T. HARVEY JOHNSTON AND M. J. BANCROFT. 33 



■others, 1917). In both these experiments Victorian calves 

 were imported ; those allowed to run with the herd became 

 infected, but those confined in an open pen with a concrete 

 floor inclose proximity to the paddock containing infected 

 ■cattle remained unaffected, as also did those kept in a 

 fly-proof pen. 



More recently work has been carried out in New South 

 Wales by Dr. Gleland and Miss Somerville (1919) who have 

 made a " nodule survey " of certain parts of that State 

 which shows that nodules are more common in parts of the 

 State Avhich have summer rains than in those ^here the 

 rainy season occurs in the winter.* 



Large numbers of Tabanids have been examined at 

 Kendall, N.S.W. by trained assistants under the direction 

 of Professors S. J. Johnston and J. B. Cleland. Out of 

 several thousands of flies dissected, worms were found in 

 three (Cleland 1918, p. 27), but so far an account of these 

 parasites has not been published. 



In 1914, Mr. Henry Tryon (Ann. Rep, Dept. Agric. 

 Queensland 1914, p. 116) suggested the possibility^ that tha 

 larval worms ( Hahronema sp.) which infest the cattle fly, 

 Musca vetustissima , might represent a stage in the life history 

 of ''' Spiroptera [Onchocerca) gibsoni.'' jVIr. Tryon informed 

 us that he had some years previously mentioned the presence 

 of these worms to several individuals interested in helmin- 

 thology. We now know that the parasites in question 

 are larval stages of Hahronema muscce and H. megastoma. 

 Cleland stated in 1914 that Onchocerca larvae were not found 

 alive in the alimentary canal of Musca vetustissima 24 hours 

 after ingestion. 



A further attempt to follow out the life history of 

 0. gibsoni was made during the period November, 1918, 

 to January, 1920. Lines of work were indicated firstlj- 

 by the prevalent idea that the intermediar}' was a Tabanid, 

 and secondly by the suggestion of Dr. Bancroft that the 

 intermediary was to be found among the non-blood-sucking 

 flies living in association with cattle, eg., M. fergusoni 

 (Johnston and Bancroft, 1919). 



*Robles (Bull. Soc. Path. Exot. 12, 1919, p. U2} believes that certain 

 species of SimuUum are transmitters of 0. ccecidiens, a human Onchocerca 

 related to 0. volvulus, and recently described by Brumpt (Bull Soc Path 

 Exot. 12, pp. 464-473). 

 C 



