BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 13 



present in one fly, in the head and proboscis alone ; in. 

 another S4 worms were counted from the head, thorax 

 and abdomen. Xo specimens of H. megastoma were 

 identified in this batch. 



Experiment III. — In December, 1919, six flies bred 

 in dung of the same horse were examined. All were heavily 

 infected with both species of Habronema, H. miiscce pre- 

 dominating. 



Experiment IV. — In December, 1919, 11 flies bred ia 

 dung of the same horse were examined with the same result 

 as in Experiment III. Over 100 worms were obtained 

 from one fly, the thorax alone containing 90. 



Experiment V. — In Januarj-, 1920, twentj^-two flies 

 were bred from dung of the same horse and examined, all 

 proving to be infected with Habronema, the number ranging 

 from 39 to 97 with an average of 71. Where final stages 

 were present, both species of Habronema could be 

 identified, but H. musccB predominated as in the other 

 experiments. Details of this experiment are given later 

 when comparing the infection of native and domestic 

 flies. 



In these five series altogether CO flies Mere examined 

 and all were found to harbour Habronema, thus 100 per 

 cent, infection of M. vettistissima occurred under experi- 

 mental conditions. 



III. — MuscA TERR-S-REGiN.i; Jnstu. and Bancroft, 1920. 



This fh- was very rare in Eidsvold, onlj- 21 captured 

 specimens being examined. One of these was infected 

 with a single //. muscoe, present in the head. 



►Specimens of the species ^hen bred on infected horse 

 dung become ver^^ heavily infected with Habronema. 



In Xovember-December, 1919, ten flies bred on material 

 from horse "' 8 " were examined. All proved to be very 

 heavily parasitised bj' Habronema, both species of which 

 were present. The intensity of infection was practically 

 the same as that recorded for M. veiustissima in 

 Experiment V. 



