67 



oppressive domination of this winged scourge. In Sudanese regions, 

 it is during the dry season that the shiftings of flocks and herds, and 

 the movements of caravans and trading expeditions, that give a special 

 character to life in these parts, are rendered possible. The effect of 

 the east wind may consequently be considered as eminently favourable. 

 The harmattan combats the dispersing influences of the winter season, 

 drives back the Tsetses into their permanent haunts, and to some extent 

 cleanses a large portion of the country from the flies that infest it. 



" The intimate relations existing between the relative dispersion of 

 Tsetse-flies and seasonal meteorological influences serve to demonstrate, 

 once again, how important it is for us thoroughly to understand, before 

 evervthing, the determinism and the nature of these influences, as 

 well as the laws that govern them in the different regions of French 

 West Africa ; and, starting from these data, to follow out the biological 

 manifestations of the species of Glossina." In concluding his remarks 

 upon this topic, the author urges, on these grounds, a closer study of 

 the meteorology of French West Africa. 



RANGE OF FLIGHT. 



Dr. J. J. Simpson, who, in the Colony of the Gambia in 1911, 

 studied the bionomics of Glossina palpalis and G. morsitans form 

 submorsitans, writes as follows (142.1.) with reference to the range of 

 flight of the former species. 



" As is well known, G. palpalis prefers to remain in the shade and 

 near the ground, preferably in low scrub, and darts out into the open 

 in the full sunlight only when in search of a meal. The maximum 

 distance to which a Tsetse will venture into an area with no shade 

 is of great importance in delimiting clearings. Various estimates 

 have been given, but although one has seen Tsetse in camps separated 

 from the bush by over 200 yds. of clearing, it is not fair to assume that 

 this distance was actually and deliberately traversed in. one flight. 

 It is quite possible that these isolated examples followed the natives 

 or horses, a mode of procedure which they often adopt. On one 

 occasion, however, when on board a launch more than 100 yds. from 

 the beach, I saw a G. palpalis fly on board in the cool of the afternoon, 

 and in view of this and similar observations, 150 yds. may be put 

 down as the lowest estimate for clearing, though 200 yds., if possible, 

 should be aimed at." 



In December 1914 Dr. W. A. Lamborn (82) made some very 

 interesting " preliminary experiments " in Nyasaland, " with a view 

 to determining the range of flight of Glossina morsitans." 



" Between 4th and 22nd December," writes Dr. Lamborn, " 1,810 

 males and 312 females were captured in the Lingadzi district, where 

 the elevation is about 1,700 ft., and between 4th and 17th December 

 854 males and 66 females had been marked and released at two different 

 points at Chunzi, at an elevation of 2,420 ft., 10 miles due south of 

 the Lingadzi fly area ; and at a spot which has an elevation of 1,950 ft. 

 and is situated two miles south of the Lipimbi River and five miles 

 south of the same fly area. 



" The flies released at Chunzi were marked by snipping off the first 

 right foot through the middle of the metatarsus, an injury unlikely to 

 occur in nature, and those released at the second spot were marked by 

 snipping through the second foot on the same side. Their fitness 

 seemed to be little impaired by the operation, for test specimens fed 



