C, M. Wen YON 
311 
Eventually the nuclear division is complete and two daughter nuclei 
formed. The division of the body of the flagellate has been proceeding 
by a groove appearing between the rliizoplasts. The presence of the 
filament connecting the two halves of the kinetonucleus appears to 
arrest the division of the protoplasm for some time, but when this 
filament is ruptured the division extends to the non-fiagellate end of 
the body and the two daughter flagellates separate. 
A point of much interest in connection with the culture of these 
organisms is the presence of extremely minute forms. One frequently 
encounters examples not more than 3 /x or 4 /r in length and about 1 /x 
to 2 /i in breadth, while on several occasions I have seen smaller 
individuals barely 2 /x long and not more than 0‘5 ft in thickness. It is 
just possible in these small specimens stained with iron haematoxylin 
to make out the nucleus and kinetonucleus, The flagellum is relatively 
large. The presence of these minute forms and the possibility of others 
still smaller must be borne in mind when examinations of flies is made 
for developmental stages. It is possible that the form transmitted to 
man by the insect carrier is some such minute flagellate as this. They 
would be extremely difficult to detect amongst the debris frequently 
present in an insect’s gut. 
H. Character of the development forms of the sore parasite in bed 
bugs and Stegomyia fasciata. 
The various developmental forms in the bed bug are shown in 
PI. XII, figs. 1-21. Figs. 1, 5, 8, 10-21 are taken from a bug dissected 
forty-eight hours after feeding on the sore. The bug was opened and 
a dry film made from the contents of the stomach and another from the 
hind gut. The stomach showed a fair infection with flagellates. In 
the hind gut only a single flagellate was found. It will be seen that 
many of the forms correspond very clearly with those met with in the 
artificial cultures. Others however show various abnormalities and 
many appear to be degenerating. Figs. 10 and 14 show two such 
degenerating flagellates, while figs. 3, 9, 15, are examples of abnormal 
forms. Apparently the development is only an abortive one and a 
partial picture of what would take place in the true host. Figs. 2 and 6 
are from another bug and figs. 3, 4, 7 and 9 from a third. Some of 
these appear to be normally constituted, while others, especially the 
curious form at fig. 9, are evidently abnormal. Figs. 38, 39, 41 show 
three parasites from a Stegomyia which had four feeds from the sore 
