INTERMEDIARY HOST OF FILARIA IMMITIS, LEIDY. 45- 



We are now able to give an exact account of the life-history 

 respectively of Filaria nocturna and F. immitis. Starting with 

 the sexually mature worms in man and dog, these produce embryos, 

 which swim in the blood; the mosquito in biting abstracts some 

 of the embryos; these develop in the mosquito's body and in about 

 three weeks time are capable of entering their final hosts should 

 they get a chance of so doing. Sooner or later the mosquito may 

 bite their final or definitive host, the filarise seize the opportunity 

 and pass into the puncture made by the mosquito in the skin ; 

 they now grow to sexual maturity, which probably takes about a 

 year. 



During the metamorphosis in the mosquito's body the position 

 taken up by the filarise serves to distinguish which is Filaria 

 nocturna and which F. immitis, the former being in the thoracic 

 muscles the latter in the malpighian tubes; whilst at their maxi- 

 mum development the chief characteristic mark is their size, the 

 young F. immitis being shorter and thicker than the F. nocturna. 



We have learnt that mosquitos live long periods, not a few days 

 as was formerly thought but months, and that during their life 

 time they bite frequently. 



It is a remarkable fact that in Europe the Anopheles maculi- 

 pennis plays the role of host for the malarial parasite, for Filaria 

 immitis, and it is believed also for Filaria nocturna; whilst in 

 Australia the "House Mosquito" Culex Skusii, Giles, [formerly 

 thought to be a form of Culex ciliaris, Linn.] 1 is host for Filaria 

 nocturna and F. immitis, probably also for the malarial parasite. 



I have recently found that dates, the dried fruit to be obtained 

 from the grocer, are a most excellent food for mosquitos, very 

 much better than banana [which some years ago I had discovered 

 to be a valuable food for mosquitos in confinement]. Dates, as 

 food for mosquitos, have these advantages over banana, they may 



1 The "House Mosquito" of Australia appears to the writer to agree 

 with the description given in Giles' work on Mosquitos, p. 298 of Culex 

 fatigans, Wied. 



