MOSQUITO WORK IN KHARTOUM AND IN THE ANGLO-EGYPTIAN SUDAN GENERALLY 25 



in a good light. It is to be remembered that any standing water collections will harbour 

 mosquito larvae, and attention should therefore be paid to the water-closet cisterns, zeers and 

 tanks. 



"2. During the voyage, opportunity should be taken to re-oil the bilges wherever 

 possible. This should especially be the ease before starting on the return journey. AYood 

 holds are usually at fault. The difficulty can be got over by emptying these in rotation so 

 that the water in the hold can be got at and oiled once in every fortnight. Special attention 

 should be directed to zeers when these are used for storing bottles of drink. All zeers should 

 be emptied out at least once a week during the voyage. 



" 3. The thing to be avoided is returning to Khartoum with mosquitoes on board. If 

 this is done, wells and water collections in the town which have been cleared at trouble and 

 expense, are liable to become re-infected. This has happened repeatedly so that it is very 

 important that steamers should arrive clean and free. It is well to have all bilge water 

 emptied on arrival, and all steamers lying up should be inspected and treated in the manner 

 described. Similar precautions are required as regards barges, sandals, launches and any 

 vessel on which there is stagnant water. 



" Note. It has been proved that mosquitoes, as a rule, will not stay for any length of 

 time on a steamer if they are prevented from breeding out on board. (Consequently, such 

 preventive methods are effective as has been demonstrated on several occar.ions, and there is 

 no excuse, in most instances, for steamers reaching Khartoum with their bilge water, &c., 

 full of larvae and pupte, and their cabins full of adult mosquitoes." 



Sometimes it has been found advisable to employ sulphur squibs* when there were 

 many adult insects in the holds. 



It is largely due tu the efibrts of Mr. Potts, of the Steamers and Boats Department, that 

 the local launches, barges and ferry-boats have been kept free. Only those who have had to 

 deal with the laziness, procrastination and inattention of the natives in charge of some of 

 these craft, can realise how difficult his task has been, and how well he has carried it out. 



The Director and Assistant-Director of the Steamers and Boats Department have done 

 all in their- power to help the mosquito brigade, and consequently great benefit has ensued, 

 despite occasional relapses. The manager and officials of the Sudan Development and 



. II' ^''^ British 



Exploration Company have also, as a rule, done their utmost to keep the Company steamers barracks 

 free. The British Barracks are, in the main, looked after by the Medical Officer in 

 charge of British Troops. They are, as a rule, kept perfectly free, though it is worth noting 

 that they are rather subject to re-invasion by Anophelines — confirmation of the statement 

 that these mosquitoes invade the town from the east. 



It is interesting to find that the natives have developed a great liking for petroleum. 

 They seem to regard it as a panacea for every kind of winged pest, and use it to keep away 

 flies and midges. This is a curious testimony to the efficacy of Major Ross's method. 



No new genus or species has been found in Khartoum. Indeed the only constant 

 species now present is C faflijanK. P. costaIi.'< is an infrequent, but none the less unwelcome, 

 visitor. Sfec/omi/in faxfiuta has given up the struggle, and, as far as can be told, has not 

 been present for many months. It used to be a nuisance in the middle of the day. It is 

 difficult to say whence came the solitary Mucidux mentioned in the last report. It is the 

 only representative of this mouldy-looking genus yet discovered in the Sudan. Possibly the 

 Theobald India .■<pathipalpis were introduced by the train, as they were found breeding near 



• Giles. Gnats and Mosquitoes, 1902, p. 221. 



