70 



LIFE HISTORY OF HABRONEMA. 



Experiment I. — During May-June, 1919, two larvae 

 and nine pupa? of M. fergusoni bred on dung of horee " S,"' 

 on examination were all found to be infected with 

 Habronema. Owing to the small size of the embryos, 

 very few could be found in the larvae and very young 

 pupse, but in older j)up3e considerable numbers of the 

 parasite were noticed. In one pupa 35 da\'s old, 32 worms 

 were present in the head, 29 in the thorax and 30 in the 

 abdomen, making a total of 91 worms in the whole insect 

 (figs. 0-7). 



Experiment II. — During June-July, 1919, a few 

 larvae collected in cow dung were transferred to horse dung 

 of unknown origin ; eight flies which emerged were used 

 to test the escape of Habronema from flies. The result 

 of dissection after death is given. 



Total worms, 487 ; average per fly, 61. 



Experiment III. — During July-August a few larvae were 

 collected and transferred to horse dung in the same manner 

 as in Experiment II. Some of these larvae Avere almost full 

 gro\Mi at the time of transference. Of 14 flies which were 

 examined 13 were found to be infected \vith Habroyiema, 

 both species being present. The numbers ranged from 

 18 to 46 in those in which a complete count was made. 

 In one 27 worms occurred in the head, 10 in the proboscis, 



