TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 237 
Batch of Oct. 19th, 1905.—A number of freshly-caught 
Entebbe flies were fed on Monkey 478. At the same 
time smears were made of the monkey’s blood, which showed 
trypanosomes rather scanty but comprising typical long, 
slender, and short, stumpy forms, as well as others of more 
indifferent type (figs. 11-13). 
Oct. 20th (twenty-four hours after infection)—One fly 
dissected. The digestive tract was gorged with blood. 
Trypanosomes were very scanty in the red blood, more 
abundant in the black. Smears were made of both, and 
showed the typical slender and stout forms well differentiated, 
but rather scanty in number; the stout forms rather in 
eXCess. 
Oct. 21st (forty-six to fifty hours after infection).—Four 
flies were dissected (three males, one female). In all of them 
only black blood was found; in one no trypanosomes were seen, 
but in the other three flies active trypanosomes of moderately 
slender type were noted. Smears made showed trypanosomes 
present, but scanty in number, in all four flies. The trypano- 
somes were long, varying from moderately slender to 
moderately stout in type, usually very granular, sometimes 
vacuolated (figs. 78-80). Dividing forms were seen. 
Oct. 22nd.—Three flies were dissected. The first fly 
(female, seventy hours after infection; re-fed Oct. 21st) had 
the stomach and intestine very full of red and black blood 
respectively ; the black blood contained a few crystals. 
Trypanosomes were fairly numerous in the black blood and 
of slender, active type, similar to T. grayi. One that was 
watched moved rapidly “en fléche ” across the field, and was 
difficult to keep in view. None were seen in the red blood 
-or in the proventriculus. Smears were made both of red and 
black blood ; in the former no trypanosomes were found. In 
the smears of the black blood the trypanosomes were not 
very numerous, but very uniform in type (figs. 93-96). They 
were all of considerable length, moderateiy stout or moderately 
slender. (Their slender appearance in life is perhaps to be 
taken in a proportionate sense—that is to say, it was their 
