CARRIERS OF FILARIA 105 



proboscis penetrate the skin, possibly through the ducts 

 of the sweat glands. The mature larvas are thus again 

 introduced into man. The further stages in the develop- 

 ment of the sexless larvae to the sexual adults have not 

 yet been traced. 



It will be seen, therefore, that given suitable mosquitoes 

 which will live for ten to fourteen days after biting a 

 person with filaria, these can in turn either reinfect the 

 same person or infect other people. 



The number of species of mosquitoes which can carry 

 tilaria is very large, but the full stage of development 

 has been shown not to occur in all. Several of the 

 Anophelina can convey filaria Myzomyia ' rossii, Myzo- 

 rhynclius sinensis and M. barbirostris, and Pyretophorus 

 costalis are the more important examples. Of the Culi- 

 cines there are several species of Culex, Mansonoides, 1 &c., 

 but Culex fatigans and Mansonoides uniformis are the main 

 carriers. Stegomyia fasciata and S. scutellaris are not 

 suitable hosts, as the full development of this filaria will 

 not take place in them. S. pseudoscutellaris is an 

 excellent host, and has been shown by Bahr to be the 

 important host in Fiji. It is a day-feeding mos- 

 quito, and possibly the absence of periodicity in the 

 embryo may be connected with this. 



The dangerous mosquitoes are those that are most 

 thoroughly domesticated, that is, frequent human habi- 

 tations and remain in or near them. Culex fatigans is the 

 most important carrier, but Mansonoides uniformis is in 

 some places of equal or greater importance. Occasion- 

 ally, no doubt, some of the other carriers do convey 

 the disease, but comparatively rarely. 



The most important species to be considered as carriers 

 of Filaria bancrofti are therefore (i) Culex fatigans, (2) 

 Mansonoides uniformis, and (3) Stegomyia pseudoscutellaris. 

 A knowledge of the life-history of these mosquitoes is 



1 Panoplites and Mansonia were names previously given, but had 

 been used for other species of animals. 



