BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 67 



Experiment III. — In August, 1919, eight flies bred 

 from dung of horse '" S " were examined. All proved to 

 1)0 infected with Habronema, both species being present. 

 No record was kept of the number of worms found in each 

 case. 



Experiment IV. — In August-September, 1919, six flies 

 bred from dung of horse '" S " were examined. All were 

 infected with Habronema, the number ranging from 1 to 25, 

 both species of Habronema being present. 



Experiment V. — In December, 1919, fifty flies, bred 

 from hortee dung from the stable referred to in Experiment I., 

 were examined, but none were infected with Habronema. 



Experiment VI — In January, 1920,, forty-six flies, 

 bred from dung of horse " 8 " were examined, 36 proving 

 to be infected with Habronema, the amount of infection 

 ranging from one to 20 worms, with an average of four. 

 Details of this experiment are given later when contrasting 

 the infection of native and domestic flies. 



Totals. 

 Experiment J. . . 39 examined . . 32 infected 

 Experiment II. . . 16 examined . . 16 infected 

 Experiment III. . . 8 examined . . 8 infected 

 Experiment IV. . . 6 examined . . 6 infected 

 Experiment V. .. 50 examined .. infected 

 Experiment VI. . . 46 examir ed . . 36 infected 



165 examined .. 98 infected or 59 jjer cent. 

 or omitting Experiment V. (in which case the dung used 

 was almost certainly uninfected with Habronema) , the totals 

 are 115 examined, 98 infected, i.e., 82 per cent. 



During February, 1920, we examined 77 specimens 

 of M. domesfica bred out from horse dung obtained from 

 a stable in Brisbane, 37 being infected, 23 with H. miiscce 

 alone, three with H. megastoma alone, two with both 

 species, and nine in which the species present were not 

 recorded. The percentage of infected flies was thus 48. 

 The number of worms present ranged from 1 to 16. 



