THE TOLL OF THE MOSQUITO 13 



bancrofti, which causes elephantiasis, can be viewed as serious. 

 These worms are transmitted to man by mosquitoes, Culex 

 fatigans apparently being considered as the chief offender. 



The most important filariae of man, according to Rosenau, 1 

 are: 



" (1) Filaria bancrofti, the larva of which is known as Filaria nocturna, 

 appearing in the blood at night and occurring in all tropical lands, includ- 







*%4 





"•vast ^ 



/ 

 J 



L. H. WILDEIi 



Fig. 11. — Filariae (without sheath) in thoracic muscles of Culex fatigans, 

 9 hours after ingestion of filarial blood; infected at Charleston, S. C. Teased 

 preparation. 



ing America; (2) Filaria loa, the larva of which is known as Filaria 

 diurna, occurring in the blood by day and prevalent in West Africa 

 and India ; (3) Filaria perstans, which persists in the blood both day and 

 night, and occurs in West Africa and a number of other places." 



Rosenau 1 describes the movements of filariae in the body of 

 mosquitoes fed on the blood of filarial-infested individuals as 

 follows : 



1 "Preventive Medicine and Hygiene," New York and London, 1918. 



