22G 
KEPOKT ON ECONOMIC ENTOMOLOGY 
A serious dura 
pest 
The asal fiy 
A similar plague of these insects is recorded to have occurred iu the same district some 
thirty-live years previously, when they were responsible for a large amount of damage 
to the dura crop. In the following season, however, very few were noticed. 
I have seen this bug feeding on grasses in the Upper White Nile Province in the 
neighbourhood of Taufikia, and near Nasser on the Sobat. 
The following is a translation from the Latin of Stal’s description of this insect, which 
he records from Caffraria and South Africa. 
“ Pale straw coloured. Scutellum more densely punctured towards the base. Fore¬ 
wings sometimes slightly ferruginous. Antennae, with the exception of the inner side of the 
lirst joint, three or four small spots on the ventral surface of the thorax, small discoidal 
si)ots arranged in groups of four on the ventral surface of the abdomen, marginal spots 
on the basal angles and on the apices of the segments—other than the spiracles—a spot on 
the basal half of the femur and the tarsi in part, black. Lateral margins of the anterior 
part of the thorax, a small basal area of tlie scutellum, and the apex of the scutellum, pale 
and but slightly punctured. 
“ Hind-wings very slightly infuscated, apices clear, membrane glassy, interior basal 
angle fuscous. Veins generally slightly infusoate. 
“ Second and third joints of antenme subequal. Eostrum extending to the middle of 
the venter. 
“ Lf'iKjtli, 7-8^ mm. Breadth, 4-4^ mm.” 
It is difficult to account for the sudden increases in numbers of aii insect which usually 
is not sufficiently common to justify its being ranked as a pest. Certain climatic and other 
conditions are presumably necessary to enable it to multiply to any very great extent, and it 
is foi’tmiate that these conditions do not more often obtain. 
The Aral Fly 
Aphis sur<jhi, Theob. 
This destructive aphis has recently been recorded from Northern Nigeria, and also 
from South Africa, where it attacks a species of sorghum known as Kaffir corn.* 
In the Sudan it appears to coniine its attentions mainly to the dura grown on the 
river banks — Beluha, crops — the rain crops in the desert being as a rule free from this pest. 
In the earlier stages of an attack of asal fly, the aphides may be found in small colonies 
on the undersides of the leaves. Each colony usually consists of a winged viviparous 
female and nundjers of larvae and apterous viviparous females. These latter produce young 
))arthenogenetically. 
Like the other members of the family Aphidtr, the asal fly increases in numbers with 
extraordinary rapidity, and soon the undersides of nearly all the leaves of the infested 
plants are covered with these tiny insects. Honeydew is secreted in vast quantities, 
and this, falling on to the leaves below, chokes up the stomata and so prevents res^iiration. 
Large numbers of flies, bees, ants and other insects are attracted by the honeydew, 
and by their presence the infestation of a few isolated plants among the crop can be 
detected. 
The attack is not usually noticed until it has become general, and by that time the crop 
has been more or less ruined. It is then that the asal fly apparently leaves the dura 
and, in all probability, migrates to some other plant. 
^ Theobald, F. V., Report on Eco)ioniic Zoolopy, fur year ending April 1st, 1907, li. 149. 
