360 RUPERT W. JACK—OBSERVATIONS ON THE 
tree was away from the influence of the river, so far as providing shade in 
August was concerned, and there were no Glossina congregating near it. Pro- 
bably the larvae were deposited when the surrounding trees were in leaf 
(Pl. X XI, fig. 2). 
(10) Ababa tree (botanical name unknown) on level ground near the river. 
The grass had been burnt off on the previous day ; soil sandy, but dead leaves 
and leaf mould absent. One live pupa was found sheltered under a hollow made 
by previous grass-fires in the trunk. The soil sloped down towards the trunk, 
but the pupa was in a ridge of soil against the trunk itself (Pl. X XI, fig. 1). 
(11) Mvumila tree (probably A’rkia acuminata) on a bank sloping sharply to 
the river. Three puparia found in a protected position close to the trunk on 
the upper side ; soil loose and sandy, vegetable debris abundant. 
Searching in the leaf mould, ete., beneath bushes on the banks of the 
river, near the trees where the pupae were found, again proved fruitless at 
Sinombi, and this, coupled with the results at Manzituba, and the very prolonged 
searches made in such situations near the Gorai River, Lomagundi, in November 
and April, leads me to the opinion that such spots are rarely if ever selected for 
the deposition of the larvae. The tsetse-fly is such a comparatively slow breeder 
that it can scarcely afford to expose its pupae to the scratchings of the game 
birds which frequent exactly the same haunts as the fly during the dry weather, 
and often in amazing numbers. Along the Gorai River in November the 
numbers of guinea fowl, “ pheasant ” (Pternistes) and “redwing” (Francolinus) 
were astonishing. They rose at almost every step along the banks, and all the 
ground under the bushes had been scratched over and over again. In April 
they were, however, not more than ordinarily abundant. 
It has already been stated that G. morsitans congregates on the shady banks 
of rivers and borders of vleis in the dry weather. In the wet season, when the 
forest is shady, the fly is much more generally distributed through the veld. 
This statement is based on the following observations :—(a.) In the Hartley 
district there are one or two farms on the railway line, and within three or four 
miles of a fly-belt on the Surisuri River. It was found that for three consecutive 
years some cattle on these farms became fly-struck in February and March, but 
no cases occurred during the dry weather. The wet season opens in December 
there. The writer took almost monthly observations on the fly-belt in 1909-10, 
and the fly was taken only near two tributaries of the Surisuri during the dry 
weather. In February, 1910, however, fly was found in the bush at several points 
away from these tributaries, and oné specimen on the borders of one of the farms 
where cattle had been struck, within a mile and a half of the homestead, and 
this (an important factor) on the outward journey. (b.) Below the Escarpment 
in Lomagundi, in November, 1910, . morsitans, was found congregated on 
the Gorai River, and on the Dandi and Ambi Rivers near their junction, and 
also in the shady borders of a vlei not far from the Dandi. In April the fly was 
not congregated at any of these places. Near the Gorai River, it occurred 
perhaps mostly in the mopani belts, a mile or two from the river, but was to be 
found all over the veld, and the same state of things was observed near 
the Ambi and Dandi Rivers, and in the vlei mentioned above. (c.) Near 
