﻿104 
  RUPERT 
  W. 
  JACK 
  — 
  TSETSE 
  FLY 
  

  

  two 
  or 
  three 
  were 
  encountered, 
  and 
  occasionally 
  none 
  at 
  all. 
  The 
  belt 
  has 
  been 
  kept 
  

   under 
  observation 
  since, 
  and 
  there 
  has 
  been 
  no 
  sign 
  of 
  increase. 
  Losses 
  from 
  trypano- 
  

   somiasis 
  in 
  cattle 
  have 
  decreased 
  in 
  this 
  part 
  of 
  the 
  district 
  ; 
  in 
  fact, 
  until 
  a 
  con- 
  

   tractor, 
  presumably 
  emboldened 
  by 
  the 
  general 
  immunity, 
  actually 
  kept 
  and 
  worked 
  

   his 
  spans 
  in 
  the 
  very 
  heart 
  of 
  the 
  fly-belt, 
  they 
  had 
  nearly 
  ceased, 
  and 
  cattle 
  are 
  now 
  

   kept 
  and 
  worked 
  where 
  it 
  would 
  have 
  been 
  fatal 
  to 
  have 
  done 
  so 
  formerly. 
  Tsetse 
  

   has 
  not, 
  however, 
  altogether 
  disappeared. 
  The 
  last 
  specimens 
  submitted 
  to 
  the 
  

   Department 
  of 
  Agriculture 
  were 
  taken 
  by 
  a 
  farmer 
  in 
  August 
  1912, 
  and 
  Dr. 
  Mackenzie, 
  

   of 
  Hartley, 
  reported 
  having 
  encountered 
  a 
  small 
  patch 
  on 
  the 
  Hartley-Golden 
  Valley 
  

   road 
  the 
  following 
  November. 
  The 
  cases 
  of 
  trypanosomiasis 
  amongst 
  the 
  cattle 
  

   working 
  in 
  the 
  heart 
  of 
  the 
  old 
  fly-belt 
  indicate 
  that 
  a 
  few 
  tsetse 
  are 
  still 
  to 
  be 
  met 
  with. 
  

   The 
  presence 
  of 
  cattle 
  in 
  the 
  former 
  haunts 
  of 
  the 
  game, 
  where 
  fly 
  still 
  persists 
  in 
  very 
  

   small 
  numbers, 
  might 
  conceivably 
  have 
  even 
  caused 
  a 
  small 
  increase 
  of 
  the 
  pest 
  since 
  

   last 
  year, 
  though 
  the 
  clearing 
  of 
  the 
  bush 
  would 
  eventually 
  counteract 
  any 
  tendency 
  

   of 
  this 
  nature. 
  

  

  The 
  lingering 
  of 
  the 
  fly 
  does 
  not, 
  of 
  course, 
  affect 
  the 
  broad 
  facts 
  of 
  the 
  situation, 
  

   seeing 
  that 
  the 
  game 
  had 
  not 
  been 
  altogether 
  destroyed. 
  The 
  important 
  fact 
  is 
  that 
  

   in 
  this 
  district 
  alone 
  in 
  Southern 
  Rhodesia 
  has 
  tsetse 
  decidedly 
  decreased 
  of 
  late 
  years, 
  

   and 
  here 
  the 
  game 
  has 
  been 
  greatly 
  reduced 
  by 
  artificial 
  means. 
  In 
  other 
  districts 
  

   where 
  permanent 
  fly-belts 
  occur 
  the 
  game 
  has 
  become 
  more 
  abundant 
  and 
  the 
  fly 
  has 
  

   increased 
  and 
  extended 
  its 
  range 
  greatly 
  since 
  1896. 
  It 
  is 
  interesting 
  also 
  to 
  note 
  

   that 
  the 
  greatest 
  and 
  most 
  rapid 
  extension 
  has 
  occurred 
  in 
  those 
  parts 
  of 
  the 
  territory 
  

   where 
  game 
  is 
  most 
  abundant, 
  as 
  in 
  the 
  Sebungwe 
  district 
  and 
  certain 
  parts 
  of 
  the 
  

   Zambesi 
  Valley. 
  

  

  We 
  have, 
  therefore, 
  south 
  of 
  the 
  Zambesi 
  River 
  a 
  very 
  logical 
  chain 
  of 
  evidence, 
  

   so 
  far 
  as 
  it 
  goes, 
  suggesting 
  the 
  necessity 
  of 
  big 
  game 
  to 
  the 
  tsetse-fly, 
  namely, 
  the 
  

   retirement 
  of 
  the 
  fly 
  before 
  civilisation 
  under 
  circumstances 
  difficult 
  to 
  dissociate 
  

   from 
  the 
  effect 
  of 
  game 
  destruction, 
  the 
  general 
  disappearance 
  or 
  great 
  reduction 
  

   of 
  the 
  fly 
  coincident 
  with 
  the 
  general 
  reduction 
  of 
  the 
  game 
  by 
  rinderpest, 
  the 
  increase 
  

   and 
  spread 
  of 
  the 
  fly 
  again 
  corresponding 
  with 
  the 
  increase 
  of 
  the 
  game, 
  and, 
  finally, 
  

   the 
  reduction 
  again 
  of 
  the 
  fly 
  locally 
  coincident 
  with 
  the 
  removal 
  of 
  the 
  game 
  by 
  human 
  

   agency 
  in 
  that 
  particular 
  spot. 
  

  

  The 
  writer 
  is 
  well 
  aware 
  that 
  something 
  more 
  than 
  these 
  facts 
  will 
  be 
  required 
  

   before 
  the 
  theory 
  of 
  the 
  vital 
  connexion 
  of 
  the 
  two 
  forms 
  of 
  fife 
  is 
  accepted, 
  especially 
  

   as 
  some 
  contradictory 
  evidence 
  has 
  been 
  brought 
  forward 
  elsewhere. 
  On 
  account 
  

   of 
  the 
  nature 
  of 
  the 
  problem, 
  however, 
  final 
  proof 
  could 
  only 
  be 
  constituted 
  of 
  an 
  

   accumulation 
  of 
  circumstantial 
  evidence 
  pointing 
  in 
  the 
  same 
  direction, 
  and 
  the 
  

   Hartley 
  experiment 
  in 
  this 
  territory 
  appears 
  to 
  be 
  the 
  first 
  definite 
  effort 
  to 
  obtain 
  

   direct 
  evidence 
  on 
  the 
  point. 
  The 
  experiment 
  was 
  not 
  carried 
  out 
  with 
  the 
  scientific 
  

   detail 
  that 
  would 
  undoubtedly 
  have 
  rendered 
  it 
  more 
  valuable, 
  but 
  nevertheless 
  the 
  

   result 
  is 
  very 
  significant 
  in 
  conjunction 
  with 
  events 
  elsewhere. 
  At 
  the 
  present 
  time 
  

   it 
  may 
  be 
  said 
  that 
  nearly 
  all 
  the 
  known 
  facts 
  in 
  South 
  Africa 
  either 
  strongly 
  support 
  

   the 
  positive 
  theory 
  or 
  are, 
  at 
  any 
  rate, 
  not 
  inconsistent 
  with 
  it. 
  Years 
  before 
  the 
  

   rinderpest 
  epizootic 
  it 
  was 
  the 
  general 
  opinion 
  amongst 
  hunters 
  (vide 
  quotations 
  in 
  

   Austen's 
  " 
  Monograph 
  of 
  the 
  Tsetse 
  Flies 
  ") 
  that 
  " 
  the 
  fly 
  would 
  disappear 
  with 
  the 
  

   game." 
  The 
  apparent 
  effect 
  of 
  the 
  rinderpest 
  was 
  confirmatory 
  to 
  an 
  amazing 
  degree, 
  

  

  