METAMORPHOSIS OF FILARIA BANCROFTI, COBB. 61 



the rudimentary intestine, can be seen from the mouth to the 

 anus; the body protoplasm, at first homogeneous, has been changed 

 into large cells with numerous vacuoles ; in ten days the intestine 

 presents a double line, the large cells have given place to very 

 small cells, Fig. 5; from this time on to the seventeenth day most 

 remarkable changes occur too intricate and difficult to describe ; 

 in seventeen days thereabout the young filaria has attained its 

 maximum development as far as its life in the mosquito is con- 

 cerned ; it now awaits the chance of gaining entrance to the 

 human host ; in the event of which, we presume that it will start 

 upon a second metamorphosis, the final alternation of generations, 

 in which it grows to the length of three or four inches and 

 becomes sexually mature. 



It remains to be proved that these young filarise will become 

 sexually mature in the human host ; I have elsewhere 1 suggested 

 how this might be accomplished, viz., by inducing a life-sentenced 

 prisoner to swallow some mosquitoes bearing filarise on condition 

 that he be given a free pardon. 



Besides proving that the Culex ciliaris, Linn, is an efficient 

 host for Filaria noctuma, I have shewn that two other species of 

 mosquito are not hospitable, viz., Culex notoscriptus, Skuse, and 

 C. annulirostris, Skuse. Both these mosquitoes will live in con- 

 finement at least twenty days. Culex notoscriptus sucks out plenty 

 embryos, but as far as I have seen none of these ever migrate to 

 the thorax; they appear to have been killed by the salivary juice. 

 Only rarely do some embryos migrate in the case of Culex annuli- 

 rostris; after two days however, any that did reach the thorax 

 have died and been absorbed. Other mosquitoes have been 

 experimented upon, but as I have been unable to keep these alive 

 sufficiently long for the final stage of the metamorphosis, it is 

 impossible to say definitely that they are not hospitable, yet every 

 thing tends to that conclusion. 



In the case of Culex hispidosus, Skuse and C: vigilax, Skuse, 

 these two species live about seven days in confinement, and a 

 1 Australasian Medical Gazette, March 20, 1899. 



