143 



cloths smeared with bird-lime caught 110,691 Tsetse-flies. The work 

 was continued subsequently without intermission, and the diminution 

 in the numbers of G. palpalis in all parts of the island where the 

 sanitary measures detailed above were carried out is stated to have 

 been beyond dispute. As a case in point Surgeon-Captain Da Costa 

 mentions the Roca Sundy Plantation, where, at the commencement of 

 the work of the Commission, from 9,000 to 10,000 Tsetse were caught 

 every month. In October 1913 the number of had fallen to 988, and 

 in November to 380, in spite of the fact that twenty-two men were 

 employed for the purpose instead of the original seven. At Porto Real 

 the initial monthly total of 7,000 fell in October 1913 to 314. In 

 round numbers the catch for the entire island amounted in October 

 1912 to 15,970 flies, and in October 1913 to 2,300. Lastly the report 

 of Surgeon-Captain Da Costa for February and March 1914, shows 

 the complete success of the bird-lime method, in conjunction with the 

 other measures of prophylaxis. While in February and March of the 

 previous year 173 men still caught respectively 11,865 and 9,450 flies, 

 38 men, operating in the plantation that had been the worst infested, 

 failed to catch a single fly during the month of March 1914. After 

 1 1th April 1914 the offer of a reward of 5 escudos 1 for every fly failed to 

 produce even one Tsetse, so that in the Island of Principe the total 

 extermination of G. palpalis would seem to have been achieved. 



Experiments in trapping by aid of bird-lime, which met with less 

 success, have also been made in Belgian Congo, German East Africa 

 (Tanganyika Territory) and Nyasaland. 



The Mission Scientifique du Katanga (Drs. Rodhain, Pons, F. Van den 

 Branden and J. Bequaert 116), which worked in Katanga (Belgian 

 Congo) from October 1910 to September 1912, made a few attempts at 

 catching Glossina morsitans at Sankisia, by means of " tanglefoot " 

 prepared from linseed oil obtained from Europe. Two natives, 

 carrying on their backs sheets of tanglefoot measuring 7 by 11 in., set 

 out at fixed times ; one of them was provided with a fly-net, which he 

 was accustomed to use, and was told to catch G. morsitans. On the 

 return of the ooys it was found that the total number of Tsetse caught 

 by means of the tanglefoot was 134, while the bag made with the single 

 net amounted to 145. 



According to Dr. Rodhain, the results of these experiments are in 

 agreement with those obtained by the German investigators, who 

 worked on a larger scale, and show that a single fly-boy catches more 

 G. morsitans than two natives carrying sheets of tanglefoot on their 

 backs. Dr. Rodhain therefore concludes that the latter method does 

 not appear likely to yield appreciable results of practical importance. 



On the other hand it might be worth while to try an improved type 

 of sticky trap, described by Dr. Zupitza in the Archiv fur Schiffs-und 

 Tropen- Hygiene for June 1914 (No. 11). This trap, which is said to 

 be just as effective as a butterfly-net, and to be capable of being used 

 by one man, consists of a sheet of oxidised wire gauze, with meshes of 

 one centimetre. The gauze is made into an oval tube, completely 

 enveloping the body of the native carrying it ; openings are provided 

 for the arms, and the contrivance is kept in position by straps. Under 

 this armour the native wears a garment of porous black material which 

 can readily be washed, the object of the meshes and of the loosely 

 woven fabric being to allow the passage of emanations from the man's 

 body. A coating of tanglefoot composition, suitably viscous, is applied 



1 Equivalent in pre-war currency to about 15 shillings. 



