XIl] 



INVERTEBRATE HOSTS 



215: 



on the development is well shewn by the number of filariae 

 that developed in each species. Stegomyia pseudoscutellaris and 

 Culex fatigans are both efficient intermediate hosts for F. han- 

 crofti ; but in the former practically all the embryos develop, 

 in the insect and come to maturity, whereas in the latter only 

 two or three ever complete their development. 



The effect of temperature on the rate of development is 

 very marked ; at a high temperature the worms may be found 

 in the proboscis after six days, but during cold weather the 

 same evolution is not complete for at least 20 days, or may 

 even be totally arrested. 



The following species of mosquitoes are capable of acting as. 

 the intermediate hosts for F. bancrofti, and with further re- 

 searches there is little doubt that the list will have to be 

 considerably extended. In many cases the development in 

 the mosquito has not been followed completely : 



^ Species in which complete development has been observed. 



* Species in which in all probability complete development takes place, 

 but forms have not been actually seen in proboscis. 



' Species in which an incomplete partial development occurs. Forms 

 never reach stage suitable for proboscis. 



