NATURAL ENEMIES 
71 
of a single stout filament. In this stage it elongates 
and divides later by simple longitudinal division. In 
the postflagellate stage the organism shortens in length 
and eventually loses its filament. 
Whether the presence of these intestinal parasites 
affects the vitality of the fly is not mentioned, nor is it 
understood whether they can be transmitted to any 
other animal. 
Since the typhoid fly does not bite, it seems likely 
that such a transfer does not take place. It is inter¬ 
esting to note, however, that a parasitic flagellate of 
the same genus, namely, Herpetomonas donovani, is 
the causative organism of the tropical disease known 
as kala azar, characterized by an enlargement of the 
spleen, by irregularly recurrent fevers, anaemia and 
emaciation, usually resulting in death, and that Cap¬ 
tain Patton has discovered that the same parasite un¬ 
dergoes a transformation in the intestine of a bedbug 
(Cimex rotundatus ) in India, confirming a suggestion 
made with reasons by L. Rogers, who had previously 
discovered the flagellated stage of the parasite. When 
the blood of a kala azar patient is sucked into the ali¬ 
mentary canal of the bedbug the parasites are liberated 
by the digestive process and begin to develop from 
the second to the fifth day. There is no evidence that 
the bedbugs are infected except from human beings, 
and there is no scientific proof that human victims ac¬ 
quire the disease from the bugs. 
Another flagellate genus, Crithidia, is found in the 
intestinal tract of certain flies, and one of them has 
