BY T. HARVEY JOHNSTON AND M. J. BANCROFT. 79 



H. microstoma. The measurements of one of our specimens 

 are given in the table early in this paper, Musca domestica, 

 M, Mlli and 31. ierrce-reginoe bred ont from the same 

 material were not parasitised by this species, but by 

 both of the others ( H. muscce and H. viegastoma) . 



X. — The buffalo fly Lyperosia exigfa Meij. 



We regard it as highlj' probable that Lyperosia exigiiay 

 the buffalo fh', whose habits have been studied by Hill 

 (P.L.S., X.S.W. 41, 1916, p. 763-8) acts as a carrier of 

 Hahronema in the Northern Territory. It breeds in horse 

 dung and readily attacks horses, much in the same way that 

 its relative Stomoxys does. It would be of interest to test 

 this fly experimentally as a possible carrier of Hahronema 

 spp., especiall}' H. microstoma. Its breeding habits and 

 its relation to horses and •' fly sores '' on these animals, 

 suggest that it may also ])e concerned in causing 

 " cutaneous habronemiasis "' or swamp cancer (see later). 



Escape of the larvce from infected flies. 



Ransom (p. 15) found an active larva in moisture 

 in a jar in which flies {M. domestica) had l)een confined 

 since the previous da,y, but as many of the flies were dead^ 

 it was not known whether escape occurred l^efore or after 

 the death of the host, or whether the host had suffered 

 injury which allowed the worm to gain its libert}'. " The 

 escape of larvae from flies into water or into moiSt material 

 liable to be ingested by horses is a possible mode by which 

 infection of the final host may occur, but the fact that the 

 worms, so far as observed, are unable to live more than 

 a few days outside the body of a host goes to prove that 

 this is not a normal occurrence in their life history. The 

 fact that the proboscis is a favourite location of the larval 

 worms suggests that they may al^andon their intermediate 

 host in some such manner as Filaria larvae abandon the 

 mosquito. It is conceivable that they might escape 

 through a slight rupture of the proboscis occurring at a 

 moment when the fly was sucking moisture from the 

 mucous membrane of a horse's lips, after which they could 

 readily reach their final location in the stomach. As yet,, 

 however, no evidence of such an occurrence has been. 



