242 HE. A. MINCHIN. 
the proctodeum. The trypanosomes exhibited great varia- 
tion of form, size, and structure, but could be divided into 
four types: (1) The prevailing type was a large vermiform 
trypanosome with a very short, free flagellum, the anterior 
end blunt, and the posterior end narrow and drawn out (figs. 
138-139) ; (2) others had the anterior end more tapering, the 
posterior more or less swollen (fig. 140) ; (8) acertain number 
were broad and fat, as if about to multiply by division (fig. 142) ; 
in addition to these three types there were found (4) many small 
or medium sized, as if resulting from recent division (fig. 141) ; 
on the other hand, division stages were extremely rare. In 
all these forms from the black blood the relative positions of 
N and N were extremely variable (for further details see 
p. 190). A count made from the two best preparations gave 
the following numbers for the various types : 
Ue 7a 3. 4. 5. 6. 
Vermi- Tadpole- Large, Young, Tees: Divid- 
form. like. fat. small, ee aimee 
sized. 
Ist preparation . 80 20 14 65 34 0 
——_$———’ 
2nd preparation . 197 152 101 34 5 
Total . é it 186 166 68 5) 
Percentage . 38°6 26:49 23°64 9°67 0:71 
Nov. 11th (192 hours after infection).—One fly (male) 
was dissected; the intestine contained a small quantity of 
black blood; the stomach contained no blood but quantities 
of bacteria. No trypanosomes were found in the black blood, 
proctodeeum, stomach, proventriculus, sucking stomach, testes, 
or seminal vesicles. 
Nov. 12th (216 hours after infection).—Three flies (all 
males) were dissected ; two of them contained red and black 
blood, one only black; in all three the stomach, intestine, 
proventriculus proctodeeum, and genitalia were examined ; no 
trypanosomes were found. : ; 
Nov. 13th (240 hours after infection).—'Three flies were 
dissected. ‘The first fly (male) was gorged with blood, both 
