TRYPANOSOMES IN TSETSE-FLIES AND OTHER DIPTERA. 165 
less diminished, and there are usually numerous square 
crystals in it. The black blood stops short at the point 
where the Malpighian tubules arise, and where the proc- 
todeumcommences. The proctodeeum contains no blood, but 
a yellowish fluid in which are suspended numerous coarse 
granules showing Brownian movement. Hence in a fly 
about twenty-four hours after feeding the three regions of 
the abdominal gut, namely, stomach, intestine, and proc- 
todeum, are marked out by their respective colour—red, 
black, and pale yellow—in a way to make them easily dis- 
cernible with the naked eye. 
In the examination of a tsetse-fly for trypanosomes I 
usually began by inserting a fine capillary tube into the 
pericardial space, in order to draw up some of the fluid 
circulating in the hemoceele. It was usually possible to 
draw up a small drop of the fluid. Some flies, however, 
were very anemic and dry; such flies always proved on 
further examination to be sickly, and usually contained great 
numbers of bacteria in the gut, in which no blood as a rule 
was found. The hemoccele fluid contained always peculiar 
amoeboid éorpuscles, generally more or less fusiform, with 
each end prolonged into a pseudopodium-like process ; some- 
times one end would show two such processes. ‘The cor- 
puscles showed distinct changes of form. No trypanosomes, 
however, were found in the hemocele. The next step would 
be the removal of the dorsal integument of the abdomen, and 
the examination of the contents of the salivary glands and 
the Malpighian tubules. The salivary glands contain 
numerous corpuscles or spherules of circular contour, varying 
from about 9 to 15u in diameter, imbedded in a granular 
matrix. Each corpuscle contains an irregular spot towards 
the centre, usually angular in shape and looking like a split 
or space. With picrocarmine the corpuscle takes a pink 
tinge and the central spot a deeper colour. In the fresh 
condition the salivary corpuscles are about the same size as 
the fat-globules liberated from the fat-body, but distinguish- 
able from them by their less refringent appearance and also 
