638 



NEMA THELMINTHES 



at night, there is no difficulty for the MicrofilaricB to reach the 

 stomach of a mosquito in the tropics, and here and in its thorax 

 development proceeds. 



The mosquitoes known to be capable of serving as efficient hosts 

 for this development are : Culex fatigans Wied in the West Indies, 

 Myzomyia rossii Giles in India., Pyretophorus costalis Loew in Nigeria, 

 Panoplites africanus in Central Africa. 



Fig. 272. — Late Stage of the Development of Filaria bancrofti 

 CoBBOLD IN Culex fatiguns. 



(After Lopss, from Mense's ' Tropenkrankheiten,') 



Incomplete results have been obtained with Culex microannu- 

 latus, C. albopictus, C. tcBniatus, Cellia albimana ; and negative 

 results in C. notoscriptus, C. annulirostris, C. hispidosus, C. vigilax, 

 C. nigrithorax, C. procax, A. musivus, Myzomyia funesta, A. maculi- 

 pennis,Pulex serraticeps, Stomoxys (?), Clinocoris lectularius. 



m 



Fig. 273. — Diagram of the Development of Filaria bancrofti Cobbold 

 IN THE Thorax, Head, and Labium of a Mosquito. 



The MicrofilaricB enter with the blood into the mosquito's stomach, 

 and there escape from the sheath by rupturing it at the anterior 

 extremity. 



They then pierce the wall of the stomach, and find their way 

 into the muscles of the thorax, where they grow considerably till 

 1-5 millimetres long and 0-25 millimetre broad. 



