118 
Herpetoniomis and Crit/udia 
riagellate stages. Sometimes it is difficult to recognise the blepharo- 
plast among the volutin granules, because they both stain in the same 
way (dark crimson with Giemsa, deep black with iron-haematoxylin 
stain)^. In some cases I found anuclear preflagellate forms, but the 
presence of the volutin granules gives them a multinuclear appearance 
(Fig. .5); such cells closely resemble some stages of development 
considered by Prowazek as the end of an “ etheogenesis ” (see below). 
Diagram VII. 
Preflagellate stages of Hcrpetomonas calUphorae in the crop of the fly. 
1-2. Non-dividing forms; the nuclear karyosome shown in Fig. 1 was stained blue with 
Giemsa’s stain. 
3-4. Dividing forms ; in Pig. 4 a pseudo-mitotic division of the blepharoplast. 
5. Degenerated preflagellate; the nucleus has disappeared. 
6-7. Forms with a short external flagellum. 
1-3. Preflagellate forms of Herpetomonas calUphorae in the midgut. 
4. Transitional stage towards the formation of a full-grown Herpetomonas. 
1 Eecently, blepharoplast-like inclusions have been found in some Hematozoa 
{Halteridiuvi). It would be worth while to ascertain if these inclusions are real blepharo- 
plasts, chromidia, or simply volutin-granules. 
