146 



"4. Soaking the bands as above, and having in addition a tube of 

 citrated blood arranged according to the ingenious device 

 of Rodhain and his colleagues [see pp. 88, 89]. If desired, 

 the blood in this tube may be poisoned." 



It would be interesting to make an exhaustive trial of these various 

 methods of trapping, in regions in which nagana is rife and Glossina 

 morsitans abounds ; but it should be noted that in an experiment on 

 the above lines carried out in the Sudan by the late Captain Ranken, 

 R.A.M.C., the powerful odour of human (native) sweat entirely failed 

 to attract this species. On the other hand, in attempting to devise 

 some practical form of trap the attraction exerted upon Tsetse-flies by 

 moving objects should not be forgotten. 



The continuance of the study of the influence upon Tsetse-flies of 

 external agents, such as heat, cold, solar radiation, humidity, colours, 

 etc., is likewise of great importance. Who knows whether some small 

 discovery, insignificant though it be in appearance, may not enable us 

 to deal effectively with a scourge which is at present devastating and 

 hindering the development of Tropical Africa. 1 



As regards the pupae, the effect of certain insecticides, such as 

 . compounds containing sulphate of copper, arsenical mixtures, sulphide 

 of carbon, etc., should be investigated. 



ARTIFICIAL BREEDING PLACES. The creation of artificial breeding 

 places, leading to the concentration of the female flies and their pupae 

 in chosen spots, thus facilitating their capture and destruction, would 

 seem to be an effective method of attacking Glossina. In its simplest 

 form, such a breeding place consists of a prostrate tree-trunk raised 

 a few inches above the ground, so as to form a dark hiding-place to 

 which the pregnant fly may retire during the period of gestation. The 

 latter characteristic, as we have already learnt from the investigations 

 of Mr. LI. Lloyd and Dr. W. A. Lamborn, is the only one common to 

 all Tsetse-fly breeding places in nature (see Plate IV, Figs. 1 and 2, and 

 Plate V, Fig. 1). Needless to say, in order that artificial breeding places 

 may have a chance of being chosen by the female flies, all the natural 

 breeding places in the fly-area concerned must, so far as possible, have 

 previously been destroyed or rendered useless. Felled trees, being 

 capable of forming breeding places, must be got rid of, and clearing 

 operations must be carried out with care. The lower surfaces of 

 materials employed in the construction of artificial breeding places 

 may, as suggested by Dr. Shircore (see p. 145), be coated with bird- 

 lime or tanglefoot, in order to catch the adult flies. All pupae should 

 be collected at frequent intervals and allowed to hatch, the flies 

 produced being destroyed, but any parasites being at once released. 



A large number of artificial breecting places for G. morsitans on the 

 above lines were constructed in 1915 by Dr. Lamborn (84) in NyasalancU 

 at Rifu in the proclaimed area, and near Monkey Bay, the object being 

 to determine which trees are most favoured as resting places by the 

 pregnant female flies. The work was planned on a comprehensive 

 scale, and carried out in accordance with a well thought-out scheme, 

 in such a way as to render it easy to find the breeding places again at 

 any future time. In all cases the breeding places were formed of trees 



1 Certain species of the Tsetse-flies appear as yet to have a very restricted 

 distribution. A knowledge of the reasons for this natural limitation, as compared 

 with the great extent of the areas occupied by other species, such as G. morsitans, 

 G. palpalis, .and G. brevipalpis, would perhaps lead to the discovery of effective 

 means for the destruction of these insects. 



