FLAGELLATES OF DROSOPHILA 



379 



various forms— trypaiiosome. crithidia, leptomoxias, leishmania and cyst (Fig. 178). 

 The k'ptoinonas lorius are regarded a^ the flatjellates ^\hich develop diiectly from 

 the cysts. V>\ l)ack^^ul■d migration of the kimaophx^^t, tlie ciithidia lonn^, and 



Fig. 170. — llei-pdontona-s roiibaudi from Malpigiiian Tubes or D,-oh.ophila confasa 

 (x ca. 2,000). (After Chatton, 1912.) 



1. Malpighian tube packed with flagellates. 

 3-4. Large attached forms of the cercoplasraa type (gregarinien). 



5-9. Transitions from the leptomonas (monadien) to the trypanosome form (spermoide). 

 10-11. Stages of encystment. 



finally the trypanosome forms, are evolved. As the latter pass to tlie liind-giit, the 

 kinetoplast comes forward again, and there are again produced leptomonas forms 



Fig. 177. — Herpetomonas sp. of Dmsophila phalerafa (x ca. 2,000). (After 



Chatton and Leger, 1912.) 



This flagellate is similar to H. sp. (1) of D. confusa. 



1-2. Rhynchoidomonas forms. 3. Tryimnosome forms. 



■i-5. Encystment after looping of body. 



which attach themselves to the epithelial lining of the gut. Here they become still 

 further retracted, till the round leishmania forms which produce the cysts result. 

 Reproduction takes place in all these stages, and the reduction in size, leading to 



