62 



W. A. LAMBORN. 



originally taken, and in the case of three other flies, of flights tending to show that 

 they were on their way back also. The flies recaptured v/ere all taken at the fringe 

 of the fly area, where, on account of the greater probability of meeting with them, 

 the collectors had instructions to work. The country which they necessarily traversed 

 is all well-wooded and without open spaces, and though careful search was made for 

 released flies in directions away from the main fly area, none were obtained. No 

 flies w^ere fed previous to release. The results are appended in tabular form (Table I). 

 I propose to continue experiments on these lines, using also flies w^hich have been 

 well fed before release. 



The Proportion of the Sexes. 



Record has been kept of the numbers of tsetse-flies captured and the proportion 

 of the sexes, the results of which are appended (Table II). The number of fly boys 

 engaged in the work of collecting has not been constant, neither has the work been 

 uniform, so that no just deductions can be drawn from the figures as to the numerical 

 prevalence of the flies. 



Table II. 

 Showing captures of G. morsitans. 



Locality. 



Date. j Males. 



Females. 



Total. 



Matumbas . . . . . . i 20th Nov. 



15 



8 



23 



?> • 





. 1 21st „ 





51 



24 



75 



»> • 







24th „ 





38 



6 



44 



J J 







25th „ 





51 



31 



82 



j» • 







26th „ 





43 



18 



61 



j> • 







28th „ 





42 



24 



66 



j> • 







30th „ 





94 



19 



113 



»> • 







1st Dec. 





12 



5 



17 



Lingadzi . 







5th „ 





119 



23 



142 



J5 • 







7th „ 





104 



14 



118 



JJ • 







8th „ 





114 



38 



152 



>> • 







9th „ 





117 



24 



141 



>> • 







10th „ 





130 



40 



170 



>> • 







11th „ 





167 



18 



185 



>5 







12th „ 





133 



14 



147 



>» • 







14th „ 





115 



10 



125 



J> • 







15th „ 





175 



12 



187 



>> 







16th „ 





84 



15 



99 



i> 







17th „ 





159 



27 



186 



J> • 







21st „ 





93 



33 



126 



>y • 







22nd „ 





184 



27 



211 



Totals .. 





2,040 



420 



2,460 



Trapping Experiments. 



In accordance with Sir Patrick Hanson's suggestion, a cage of wire mosquito-proof 

 netting was constructed in a part of the Lingadzi district where tsetses are especially 

 numerous, and in this a goat was incarcerated, the outer side of the cage and the 

 undersides of branches of trees near by being smeared with bird-lime in the hope 



