TRYPANOSOMES IN TSETSE-FLIES.AND OTHER DIPTERA. 2338 
223); (6) slender forms (figs. 224-226); (7) dividing forms. 
A count gave the following numbers of each type : 
(1) (2) (3) (4) (5) (6) (7) 
Numbers. 10-. 8 7 5 19 26 2 
Percentage.. 97 338 679 4:85 1844 25-24 1-94 
The smears of the black blood showed the same types, (1) 
being perhaps rather more pronounced in its characteristics 
(figs. 226 a-231). A count gave the following results : 
(1) (2). (3) (4) (5) (6) (7) 
Numbers . 86 BL = RS} De, 3 60 13 
—_— a 
Percentage. 36°38 13 | 9:66 9:24 1:26 25:25 5:46 
The two smears made from the proctodeum gave remark- 
able results. In one after much searching a single, slender 
form was found. In the other, vast swarms of trypanosomes 
were found in certain spots ; in particular, one huge clump, 
quite visible to the naked eye, and resembling under a low 
power a section of spleen or other small-celled tissue. Away 
from these clumps trypanosomes were scanty. The majority 
of the trypanosomes were slender, Herpetomonas-lke 
forms (fig. 232), but, unfortunately, badly preserved, having 
a macerated appearance, with n often broken up. <A few 
stouter forms (fig. 253), and some pear-shaped forms without 
flagellum were also to be found. The fact that very scanty 
free trypanosomes were seen in the fresh condition indicates 
that the individuals found in the smears were probably all 
attached in clumps to the wall of the proctodzum, as noted in 
the fly of Nov. 14th (p. 245). The fact that the few free 
trypanosomes seen were non-motile, and that in the smear 
they appear macerated, indicates that the trypanosomes were 
moribund for some reason. (I have seen similar results 
follow from using a dissecting needle, which had been inad- 
vertently dipped into borax carmine.) 
Oct. 11th (forty-five hours after infection). The second 
fly of the batch was dissected; it was found to be very 
