TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 243 
red and black; no trypanosomes were found in the red or 
black blood, the proctodzeum, salivary glands, or genitalia. 
The second fly (male) had the intestine empty except for a 
small quantity of blackish fluid in the intestine ; the stomach 
was crammed with bacteria ; no trypanosomes were found in 
the stomach, intestine, proctodeum, proventriculus, salivary 
glands, or genitalia. 
The third fly (female) had a small quantity of red blood in 
the stomach, and the intestine full of black blood; it was 
found to be swarming with Trypanosoma grayi through- 
out the stomach, intestine, and proctodzum, but no trypano- 
somes were found in the salivary glands, larva, or proven- 
triculus ; one was found, however, in a teased-up ovary, but 
this was probably accidental; these excessively motile para- 
sites are often let free during dissection by accidental 
ruptures of the gut-wall, and swarm out into the salt solution 
in which the dissection is performed. 
Hxamination of the smears made from this fly gave the fol- 
lowing results: In the red blood (figs. 151-155) trypanosomes 
were excessively abundant, for the most part of moderate 
size, fairly slender, the free flagellum often very short, some- 
times long, and the relative positions of N and w extra- 
ordinarily variable (see p. 190). A count gave the following 
numbers of different types : 
Large, Large, Medium- Sea Rae 
slanule. meant Small. sized. Dividing. 
Numbers 5 BED 12; 157 Al 9 
Percentage . 52°28 2°6 34:2 8°93 LAGS 
In the black blood also the trypanosomes were very 
abundant and in the main similar in type to those in the red 
blood, perhaps rather more slender, more active in appear- 
ance (figs. 156-162) ; but in addition there occurred a small 
number of slender Herpetomonas-like forms, distinguished 
at once by their very slender form and transparent appear- 
ance; they stain feebly, and also have n in front of N (figs. 
