DISSEMINATION OF NEMATODES 185 



The occurrence of parasitic nematodes in the head of the fly is 

 of further economic interest, for although M. domestica is not a 

 blood-sucking species and the nematode previously described is 

 not of the nature of the pathogenic Filaria bancrofti, there is no 

 reason why the house-fly should not, under the necessary con- 

 ditions, carry pathogenic nematodes which might easily get on to 

 the food of man. 



