380 



FAMILY: TRYPANOSOMID^ 



cyst formation, is rather the result of successive divisions unassociated with growth 

 than to actual retraction. In this cycle it will be seen that the leptomonas forms 

 appear in two phases, so that, to use Chattou's term, the developmental cycle is 

 diphasic in contrast to that of R. roubaudi and H. sp. (1) described above, in which it 

 is monophasic. 



There is a modified cycle of development exhibited by another peritrophic form 

 often associated with H. drosophilce which is monophasic. The free leptomonas 

 forms, instead of becoming free trypanosome forms, as in H. drosophilce, pass to the 

 hind-gut as leptomonas forms, where they become smaller and attach themselves 

 to the gut wall. At the same time the kinetoplast migrates backwards, so that the 

 attached forms really have the trypanosome structure. This cycle corresponds 

 closely with that of Ilerpetomonas sp. (1), the second flagellate mentioned above, 

 and can be considered as a condensed cycle by the loss of the active trypanosome 

 stage, Avhich is only revealed after the leptomonas forms have attached themselves. 



Fig. 178. — Herpetomonas drosophilce fkom In- 

 testine OF Drosojihila confusa ( x 2,000). 

 (After Ciiatton and Legek, 1911.) 



1-2. Leptomonas forms (monadien). 

 3-8. Transformation of leptomonas into trypanosome 

 forms (trypanoide). 

 9-13. Transformation of leptomonas forms (monadien) 

 into small ovoid bodies (spermoide). 

 14. Attached forms (gregarinien) in rectum which 

 become encysted after becoming trypanosome 

 forms (spermoide). 



Fig. 179. — Herpetomonas sp. of 

 DrosopliUa p>lialerata ( x ca. 

 2,000), Free Leptomonas 

 AND Transformation of 

 attached leptomonas 



Forms (Gregarinien) into 

 Trypanosome Form (Sper- 

 moide) BEFORE EnCYST- 



MENT. (After Ciiatton 

 AND Leger, 1912.) 



Chatton and Leger, however, speak of this flagellate as Leptomonas p., as they have 

 not sufficient evidence, in the shape of pure infections in the fly, to justify separating 

 it entirely from the diphasic form, H. drosophilce. A flagellate of D. phalerata is, 

 however, very simUar to it (Fig. 179). 



The fifth flagellate is Leptomonas sp. Chatton and Leger, 1912. It, again, is a 

 Herpetomonas [H. sp. (2)], according to the definition adopted here, and differs from 

 H. drosophilce in being endotrophic and not peritrophic in the adult fly. It occurs 

 only as an intestinal parasite of the adult fly. The forms met with are similar to 

 those of //. drosophilce, with the exception that reduction in size of the body takes 

 place to a certain extent and then ceases, so that cysts are not formed. From 



