208 
KEPOKT ON ECONOMIC ENTOMOLOGY 
Cataracts as 
breeding 
places 
Sandflies in 
Khartoum 
Kilteb fly 
The first swarms usually make their appearance towards the end of November and the 
beginning of December, about the time when the wheat is being sown, but are not present 
in their largest numbers until the months of February and March. Shortly after this they 
disappear and are not noticed again until the following winter. 
They are at their worst during the hours of sunset and sunrise, when it is impossible to 
walk anywhere with comfort without a veil or smoky torch to keep them away. During the 
heat of the day, many of them rest among the vegetation ready to attack anything that 
approaches their haunts. 
At night they are harmless. 
Their habit of appearing when the wheat is sown, disappearing when the wheat is 
harvested, and apparently originating among the vegetation, has given rise, among the 
natives, to the erroneous idea that their presence is entirely due to the wheat. 
Nimilti are not usually a pest in Dongola Province, south of Debba, though a stray 
swarm sometimes reaches Merowe and the district. 
A glance at the map of Dongola Province will show that at Debba the Nile makes a 
pronounced bend. 
As the river falls in the autumn, the rocks in the cataracts immediately north of Abu 
Fatma — the Third Cataract — become exposed. The cataracts then constitute ideal 
breeding places for these tiny sandflies, which shortly afterwards emerge in myriads. 
During the winter, the wind blows steadily from the north and the Xim-itti are 
consequently borne southwards to Debba, and then, owing to the altered course of the 
river, on into the desert. In the spring, the wind changes and blows from the south, 
carrying away with it most of the Nirnitti. As the summer advances, the river rises, the 
rocks in the cataracts become covered with water, and suitable breeding places are then 
few and far between. 
The occasional swarms that occur in Merowe and the district are usually to be 
accounted for by temporary changes in the direction of the wind. Sometimes, however, as 
in the sju-ing of this year, when the river was exceptionally low, it is possible that rocks 
become exposed in other parts of the river and the swarms that appear there breed locally. 
Nivutti are by no means confined to Dongola Province, though it is usually only there 
that they occur in very large numbers. Larv® and pupae have been taken from the river at 
Abu Hamed and at Gebel Umali, while adults are frequently seen during the winter in the 
vicinity of the river from Abu Hamed to Khartoum. 
The types from which this species was originally described came from Assuan. 
Kilteb 
Simulium daiiinosum, Theob. 
Eeports of the Sleeping Sickness Commission, No. III. (1903), p. 40 
Plate XXIII., figs. 3, 5, 7 
A second and larger species of sandfly — Suimliuiti danuiosuxi — occurs in the Sudan, 
in the vicinity of the Abu Hamed, where it bears the name of Kilfeh. 
The following is a copy of the original description of the adult (tig. 3) ;— 
“ The fly is 3 mm. long, of a general black colour ; head palpi and antennie black, 
except at their base, where they are bright testaceous ; thorax black, the meso-thorax 
with bright deep golden, thick, short, curved hairs closely applied to the surface of the 
thorax. Meta-thorax black, abdomen black, shiny with short black hairs ; fore and mid 
