18 MOSQUITO WORK IN KHARTOUM, ETC.

Rarer forms

Formation of Mosquito Brigade

Breeding places

These are not the only varieties of mosquito to he encountered in Khartoum. A large species of Culex closely resembling, if not identical with Culex concolor

(probably C. tigripes) exists, but it is rare. At least one other species of Stegomyia is to be found besides Stegomyia fasciata and its variety form “ mosquito,” while

Colonel Stanton, the Mudir, sent me a very large female mosquito which I found to belong to the genus Mucidus, and which Mr. Theobald, to whom I am much indebted for help freely rendered, declared to be a variety of his Mucidus africanus}

I have recently found Theobaldia spathipalpis breeding in barrel water at Khartoum North. Sufficient has been said to show that it was necessary to take steps for destroying these insects, and especially the Anophelines. Colonel Talbot, R.E., being much interested in the matter it was not long before one was asked to send to the Senior Medical Officer, Khartoum, a statement regarding the formation of a mosquito brigade, and one was subsequently requested to take complete charge of the work. I was very glad to do so, as it gave me an opportunity of studying the mosquitoes and their breeding places, of collecting specimens and of carrying out a few experiments. A small mosquito brigade was therefore formed on the lines suggested by Major Ronald Ross.2 Two intelligent natives were obtained from Colonel Stanton, the Mudir, and quickly trained to recognise mosquitoes, their eggs, larvae and pupae, and to distinguish the culicidae from other insects. Mr. Newlove, the laboratory assistant, who by this time had also become familiar with all the stages of the mosquito, was placed in charge of these men, his knowledge of Arabic being most useful, and here I would pay a well deserved tribute to the energy and zeal he displayed in what was often hot and tiresome work. The necessary equipment was provided by Captain Rivers, E.M.C., the acting S.M.O. at that time, and it was decided to attack the mosquitoes chiefly in the larval stage. This was the more easily accomplished owing to the nature of their breeding places.

These may be classed as follows:—

1. Wells; by far the - most numerous and most ‘largely infected (see page 17). 2. Sakia pits, both along the river bank and in certain gardens (see page 15). 3. Garden tanks, practically confined to the river front (see page 17). 4. Bath-waste pits.

5. Permanent garden pools, practically only found in the Palace Gardens (see page 17).

6. Zeers (native water filters) (see page 15).

7. River pools, i.e., pools left in the banks by the falling Nile (see page 19).

8. Steamer holds, tanks, water-closet cisterns and engine rooms, also the holds of wood and other barges (see page 19).

• • Chance water collections as in old u sandals ” or barges drawn up on the river bank, and from which speedy evaporation was prevented

(see page 19).

1 Theobald. “Monograph of the Culicidae” 2 Ross. “ Mosquito Brigades ”