N. H. SWELLENGREBEL 111 
(Diagram I, Fig. 1), but often a distinct undulating membrane is present 
(Fig. 2). 
The blepharoplast may be situated near the anterior part of the 
flagellate (Fig. 1), or in the neighbourhood of the nucleus (Fig. 2); or it 
may even pass the nucleus and come to lie in the posterior part of the 
cell (Figs. 3-8), .so that a real trypanosome-facies is produced. 
Judging from the numerous intermediate stages between the 
herpetomonas- and trypanosome-forms, it is obvious that these trypano¬ 
somes do not arise by the flagellum bending hack along the body of the 
flagellate, as in Mackinnon’s Herpetomonas of Homalomyia. Trypano- 
some-like flagellates of non-bloodsucking insects have been found by 
Chatton and Alilaire (1908), Roubaud (1908), and Swingle (1911); 
Roubaud found transitional stages between the herpetomonas- and 
trypanosome-facies. Woodcock (1910) thinks these forms are not real 
trypanosomes, because an undulating membrane does not exist, the 
Diagram II. Stages of division of Crithidia calliphorae. 
1. Formation of a new flagellar root. 
2-3. Division of the blepharoplast; growing of the new flagellum. 
4-8. Nuclear division. 
flagellum passing through the cell and not alongside it. This is indeed 
the case with Roubaud’s flagellate, but in G. calliphorae I think there 
can be little doubt that a real undulating membrane occurs in the 
trypanosome-facies. These forms are 10-lG p long and 2-2'3 p broad. 
The whole flagellum is 15-23 p long; the free flagellum 4’5-9 p. 
As in Trypanosoma lewisi the blepharoplast is composed of an 
achromatic body in which 6ne or two chromatic granules are embedded. 
