TRYPANOSOMIASIS EXPEDITION TO THE CONGO 51 
The larva is broadest at the ninth and tenth segments, is roughly ovoid in 
transverse section, and has, distinctly, dorsal and ventral surfaces. At the 
junction of the two surfaces is a row of irregular protuberances, two or more being 
placed on each segment. On each protuberance is a small posteriorly directed spine 
and a small pit. The central part of the ventral surface is flattened, and at the 
posterior margin of each segment is a set of three foot-pads, transversely arranged, 
each covered with small spines directed backwards. These aid the larva in its 
movements, which are fairly rapid and peculiar in that the mouth parts are protruded 
to the utmost and the tentacula fixed, as a purchase, first on one side then on the 
other, while a wave of contraction runs along the body as each segment is contracted 
and brought forward. 
Dorsal Surface Ventral Surface Lateral Surface 
Congo Floor Maggot ( x 4-5) 
The last segment is larger than any of the others. Its upper surface is flattened, 
and looks backwards and upwards at an angle of about forty-five degrees with the 
longitudinal axis of the larva. This surface is roughly hexagonal and bears anteriorly, 
one on either side, the posterior spiracles which are seen with a pocket magnifying 
glass as three transverse, parallel, brown lines. Around this flattened surface, 
towards its border, are placed groups of rather prominent spines. The ventral 
surface of this segment is also flattened, and is thrown into folds by muscular 
contractions. The anus is situated in the anterior portion of this segment in the 
middle line, and is seen as a longitudinal slit, surrounded by a low ridge. Posterior 
to it, and on either side, is a large conspicuous spine. The anterior segment is 
roughly conical, and bears the mouth parts in front. Posteriorly, on the dorsal 
