356 



FAMILY: TRYPANOSOMID^ 



rounded posterior and tapering anterior end. The kinetoplast lies close 

 to, but still in front of, the nucleus, while the axoneme, before entering 



^!'->y 



/J 



28 



25 /' 



m ^ ^ 



Fig. 166. — Crithidia gerridis from the Water Bugs, Gerris fossarum and 

 Microvelia sp. (No. 9x460; others x 8')0). (After Patton, 1908.) 



1. Pre-fiagellate forms from mid -gut of nymph. 



2. Early stage of development of axoneme. 



3. Development of flagellum and commencing division. 

 4 and .5. Dividing forms with developing flagella. 



6 and 7. Forms evolving towards the crithidia type. 



8. Cluster of rounded fmins with developing flagella. 



9. Cluster of critliidia forms adherent to a particle by their flagellar ends. 



10-12. Elongate crithidia form. 13. Club-shaped crithidia forms. 



14. Dividing crithidia forms. 15-20. Short and narrow crithidia forms. 



21-26. Stages in development of post-flagellate forms which escape m faeces and lead to infection 

 of young nymphs. 



