XII] 



DEVELOPMENT IN MOSQUITO 



211 



being developed within the old one. Large cells appear at the 

 end of the tail and form three or four papillae which characterise 

 the larva at the end of this and during the next stage. 



Fig. 55. Filaria bancroftix 200. Stages in the development within the 

 mosquito. (After Nuttall.) a, young filaria immediately after escaping 

 from the sheath ; b, 5 days, c, 10 days, and d, 16 days after ingestion 

 by the mosquito. 



The worm is now about 1*5 mm. in length, and its breadth 

 has diminished to about one-half. The anterior end tapers 

 but is abruptly rounded off ; the posterior end also tapers 



14 — 2 



