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ON THE BIONOMICS OF THE SANDFLIES (PHLEBOTOMUS) 

 OF TOKAK, ANGLO-EGYPTIAN SUDAN. 



By Harold H. Kinc t , F.E.S. 



Wellcome Tropical Research Laboratories , Khartoum ; Government Entomologist, 



Anglo- Egyptian Sudan. 



The following observations were made during eighteen days spent at Tokar in 

 October and November, 1912. Only a limited amount of time could be given to 

 the work of searching for the breeding places of sandflies, but it is thought that 

 possibly these very brief notes may be of some interest to those engaged in 

 similar research elsewhere. 



The town of Tokar is situated about eighteen miles from the port of Trinkitat 

 on the Red Sea and some fifty-eight miles south-east of Suakin. It is the centre 

 of a cotton-growing area comprising between 30,000 and 40,000 acres watered by 

 the flood-river (or khor) Baraka. This khor comes down in flood during the 

 months of July and August and spreads over the plain. As soon as the land is 

 dry enough it is cleaned and almost the whole of it sown to cotton. A few heavy 

 rainstorms usually occur during the months of October, November and December, 

 and cotton picking extends from the latter month till May. The soil is alluvial, 

 and on drying cracks vertically to a depth of several feet, and also horizontally, 

 forming shale-like plates of varying thicknesses. There are scarcely any trees 

 and only a moderate number of low bushes. 



This cultivated area is notorious throughout the Sudan for the number and 

 bloodthirstiness of its sandflies. The adults can be found in numbers at distances 

 of at least two miles from any mud or brick w r all or building. They are equally 

 numerous on clean land growing cotton and on land on which cotton has failed and 

 which therefore supports only a few grasses and other weeds. The general 

 opinion of the officials who know the district well is that they are confined to the 

 flooded area and that they are not met with in the surrounding desert. Natives 

 who live in the town told me that there they were not troubled by them, but if one 

 spent a night in the cultivations one would meet with plenty. The land on which 

 the town is built is not flooded, being protected by a low embankment of soil. 



The main difference between the flooded and unflooded land is the presence of 

 deep cracks, referred to above, which appear in the former as soon as it begins to 

 dry out. Newstead* states that all the sandfly larvae and pupae taken by 

 Marett and himself in Malta were found living under similar conditions as 

 regards (a) presence of organic matter, (b) presence of moisture, but not in 

 excess, and (c) absence of light. The only situations where these three conditions 

 could be found together at Tokar were in the soil itself, and on flooded land the 

 cracks provided the sandfly with an easy means of access to such situations. 

 If these cracks and the soil adjoining them were the breeding places of the 

 Tokar sandflies, the reason why the adults were only found on flooded areas 

 would be explained, and I could think of no other theory which would account 

 for it. All the very limited amount of time which could be spared for, this work 

 was spent therefore in searching for larvae and pupae in the soil. 



* Annals of Tropical Medicine and Parasitology, v, no. 2, August 1911, p. 141. 



Bull. Ent. Res. iv, pt. 1, May 1913. 



29262 F 2 



