REl’ORT OF TRAVELLING PATHOLOGIST AND RROTOZOOLOGIST 
145 
Trypanosomes in Toads. Plato III., fig. 2 
In the common toad of the Sudan {Bufo regularis) trypanosomes, hiemogregarines, 
and filariiB were common. The trypanosomes were of several types, which may all he 
developmental stages of one trypanosome. 
1. Leaflike trypanosomes resembling T. rotatorimn. 
2. Large trypanosomes up to 70// in length and about 5-6// wide. 
3. Very narrow trypanosomes about 30/t long and I'5// wide. The nucleus and 
micronucleus are close together at the junction of the anterior and middle thirds of the body. 
There is a free flagellum. The presence of a trypanosome and haemogregarine in this toad 
has been noted by Dutton, Todd and Tobey. 
Flagellates in Biting Flies 
T A H A N I n 
Plate XL, figs. 1-10, 15 
As already mentioned. Dr. Balfour and I found in the intestine of Tahanus socius, the 
Seroot fly, a flagellate of the genus Herpetomonas. On the journey up to Taufikia from 
Khartoum these flies came into the floating laboratory in large numbers, attacking both men 
and animals. As this fly is most persistent in its attempts to suck blood, we thought it of 
interest to make dissections of the gut. As a result of these enquiries we found that, roughly, 
about one fly in every fifty harboured the above-named flagellates in its gut. At Taufikia, on 
the Sobat, and at other places in the Sudan, I continued the dissection of these flies and also 
other species. At Nasser, where Tahanus socius occurred in abundance, I found a much larger 
percentage of flies infected. Here it was not unusual to meet with the Herpetomonas in every 
third fly examined. At Nasser, four other species of Tabaims were examined. These were 
T.fasciatus, T. biguttaius, T. africanns, and T. par, hut only in two of the last-named species were 
Herpetomonas found. Later in the year, in the Bahr-El-Ghazal Province, Herpetomonas was 
discovered in other species, viz. T. ditceniatus, T. africanns, T. fasciatus, T. gratus, T. virgatus, 
so that altogether seven species of Tahanus were found to be infected with this flagellate. In all 
these flies, as far as could be determined by examination of the fresh and stained specimens, the 
J/erpetoMOwas belonged to one species. In the majority of flies the flagellate was in the resting 
condition and attached to the lining of the gut. It was never found as far forwards as the 
stomach, and mostly in the gut behind the Malpighian tubes. In only a few instances were 
free motile forms seen, and these in the portion of gut into which the Malpighian tubes opened 
or just posterior to this part. When only resting forms were present, as was generally the case, 
it was found that the nearer the Malpighian tubes the more did these forms resemble the free 
forms, and conversely the nearer the anus the more did they approach to the stage of encyst- 
ment. In the hindermost portion of the gut, small bodies of oval outline and with two 
chromatin dots at one end, one large and the other small, were frequently seen. These are 
undoubtedly the encysted forms of Herpetomonas, which are destined to escape to the exterior. 
Such cysts have been described by Prowazek, Minehin, and others. They bear some 
resemblance to the encysted forms of Hexamitus from the gut of mice (Wenyon). 
A section of the gut in the neighbourhood of the Malpighian tubes is figured on Plate XI., 
fig. 15. It will he seen that the whole surface of the gut is lined with Herpetomonas attached 
by their flagellar ends. Various forms of these parasites, as seen in films stained with Giemsa 
stain, are shown in Plate XI., figs. l-IO. It will be evident from the figures, which are all drawn 
to one scale, that there is a gi’eat variation in the size of both the free and resting forms. 
K 
Three forms 
of trypano¬ 
some in the 
common 
Sudan toad 
Flagellates in 
biting flies 
Herpeiomon as 
in Seroot flies 
