TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 245 
free and swimming actively and also adherent to the wall in 
large patches, resembling, under the low power of the micro- 
scope, patches of mould, the whole mass quivering and 
vibrating with the movements of the flagella. No trypano- 
somes were found in the testes, seminal vesicles, salivary 
glands, or proventriculus. 
Hxaimination of smears gave the following results: ‘The red 
blood showed a preponderance of large forms (fig. 173), 
together with a certain number of small or medium-sized try- 
panosomes (fig. 171) and a few division stages; slender forms 
(fig. 172) were also found, but were very scarce. A count 
gave the following results. 
Large. Medium. Small. Male. Dividing. 
Numbers : 237 64. 63 3 14 
Percentage . 62:2 16°79 16°5 0°78 3°6 
The transitional region between the red and black blood 
showed a similar state of things, but the trypanosomes were 
rather smaller, not attaining such great length as in the red 
blood (figs. 174-176). Division stages were frequent, and a 
series has been drawn from the two smears of this region 
(figs. 204-216). No slender forms were found. 
The black blood (figs. 177-182) showed in the smears a 
few large forms, and some of medium size (fig. 177), but the 
great majority were small forms, like those recently originated 
from division. In one slide forms were found, which, by 
their shape—especially the pointed hinder extremity (fig. 178) 
—approached the Herpetomonas type, but true H-forms 
were not found. A few round forms also were found. A 
count resulted as follows: 
euee oe | | Small Round. 
Numbers. : ‘ ‘ 162 749 23 
Percentage. BP seh, wide 80°1 2°46 
Thus over 80 per cent. were small forms, all of them with 
nm in front of N, or at the side; none with » behind N. In 
