﻿102 
  RUPERT 
  W. 
  JACK 
  — 
  TSETSE 
  FLY 
  

  

  at 
  the 
  time, 
  and 
  are 
  probably 
  as 
  approximately 
  correct 
  as 
  they 
  can 
  be 
  made 
  at 
  this 
  late 
  

   date. 
  By 
  comparing 
  the 
  red 
  areas 
  with 
  those 
  coloured 
  green, 
  which 
  represent 
  the 
  

   range 
  of 
  the 
  fly 
  at 
  the 
  present 
  time, 
  the 
  extent 
  to 
  which 
  the 
  pest 
  has 
  spread 
  since 
  the 
  

   rinderpest 
  can 
  be 
  realised. 
  

  

  Our 
  information 
  concerning 
  the 
  spread 
  of 
  tsetse 
  in 
  the 
  Sebungwe 
  district 
  is 
  more 
  

   detailed 
  than 
  it 
  is 
  in 
  regard 
  to 
  other 
  parts. 
  In 
  1907, 
  Mr. 
  Gielgud 
  submitted 
  a 
  map 
  

   showing 
  how 
  the 
  fly-belts 
  had 
  extended 
  up 
  to 
  that 
  time, 
  and 
  the 
  writer 
  has 
  since 
  been 
  

   able 
  to 
  supplement 
  these 
  observations. 
  In 
  this 
  way 
  the 
  material 
  for 
  Map 
  II 
  has 
  been 
  

   collected. 
  This 
  map 
  shows 
  the 
  limits 
  of 
  the 
  fly 
  after 
  1896 
  (red), 
  in 
  1904 
  (blue), 
  in 
  1907 
  

   (brown), 
  in 
  1910 
  (yellow), 
  and 
  at 
  the 
  present 
  day 
  (green). 
  In 
  regard 
  to 
  the 
  limits 
  for 
  

   1910, 
  it 
  should 
  be 
  noted 
  that 
  the 
  line 
  drawn 
  from 
  the 
  southernmost 
  point 
  to 
  the 
  

   junction 
  of 
  the 
  Busi 
  Kiver 
  with 
  the 
  Sengwa 
  is 
  to 
  some 
  extent 
  hypothetical. 
  Tsetse 
  

   was 
  first 
  taken 
  on 
  the 
  Sengwa 
  in 
  that 
  year 
  at 
  the 
  junction 
  with 
  the 
  above-mentioned 
  

   river, 
  and 
  the 
  writer 
  fixed 
  the 
  southern 
  boundary 
  in 
  May. 
  The 
  southward 
  movement 
  

   of 
  the 
  fly 
  had 
  been 
  very 
  rapid, 
  and 
  had 
  driven 
  away 
  the 
  only 
  native 
  chief 
  possessing 
  

   cattle 
  in 
  the 
  district. 
  This 
  was 
  Pashu, 
  whose 
  old 
  kraal 
  is 
  shown 
  on 
  the 
  Mlendi 
  river 
  

   on 
  the 
  map. 
  This 
  native 
  subsequently 
  moved 
  his 
  cattle 
  back 
  to 
  his 
  old 
  kraal 
  and 
  lost 
  

   very 
  heavily 
  from 
  trypanosomiasis, 
  whilst 
  some 
  Government 
  mules 
  stationed 
  at 
  a 
  

   kraal 
  within 
  three 
  miles 
  of 
  the 
  same 
  spot 
  also 
  died 
  about 
  the 
  same 
  time. 
  The 
  present 
  

   day 
  boundaries 
  have 
  been 
  fixed 
  with 
  some 
  degree 
  of 
  accuracy, 
  but 
  waterless 
  stretches 
  

   of 
  country 
  have 
  had 
  to 
  be 
  crossed 
  by 
  hypothetical 
  lines. 
  The 
  isolated 
  belt 
  on 
  the 
  

   lower 
  Sengwa 
  was 
  discovered 
  last 
  year 
  (1913). 
  It 
  is 
  situated 
  in 
  rough 
  uninhabited 
  

   country, 
  and 
  may 
  have 
  been 
  overlooked 
  for 
  some 
  years. 
  The 
  fly 
  is 
  very 
  thick 
  at 
  one 
  

   spot 
  close 
  to 
  the 
  Sengwa 
  in 
  this 
  belt. 
  

  

  The 
  Sebungwe 
  area 
  is 
  of 
  special 
  interest 
  because, 
  apart 
  from 
  the 
  three 
  officers 
  of 
  the 
  

   Native 
  Department 
  until 
  last 
  year 
  stationed 
  at 
  Kariyangwe, 
  there 
  have 
  been 
  no 
  white 
  

   men 
  living 
  in 
  the 
  district 
  to 
  the 
  west 
  of 
  the 
  Sengwa 
  river, 
  the 
  natives 
  are 
  practically 
  

   unarmed, 
  and 
  the 
  processes 
  of 
  nature 
  have 
  not 
  been 
  interfered 
  with 
  by 
  human 
  agency. 
  

   Big 
  game 
  has 
  increased 
  greatly 
  and 
  is 
  now 
  very 
  abundant 
  in 
  certain 
  parts. 
  

  

  Turning 
  now 
  to 
  the 
  Hartley 
  district 
  we 
  are 
  confronted 
  with 
  an 
  exactly 
  opposite 
  

   situation. 
  Here 
  human 
  agency 
  has 
  been 
  at 
  work 
  for 
  years 
  and 
  natural 
  conditions 
  

   have 
  been 
  modified. 
  The 
  heart 
  of 
  the 
  fly-belt 
  on 
  the 
  railway 
  line, 
  which 
  is 
  the 
  one 
  to 
  

   which 
  it 
  is 
  desired 
  to 
  call 
  particular 
  attention, 
  is 
  about 
  the 
  head- 
  waters 
  of 
  the 
  tribu- 
  

   taries 
  of 
  the 
  Suri-suri 
  river. 
  It 
  is, 
  in 
  fact, 
  usually 
  known 
  as 
  the 
  Suri-suri 
  belt. 
  There 
  

   is, 
  unfortunately, 
  but 
  little 
  to 
  be 
  learnt 
  from 
  a 
  comparison 
  between 
  the 
  extent 
  of 
  the 
  

   belt 
  after 
  1896 
  and 
  its 
  extent 
  to-day, 
  because 
  it 
  is 
  nearly 
  surrounded 
  by 
  mines, 
  and 
  

   although 
  the 
  heart 
  of 
  the 
  belt 
  was, 
  up 
  to 
  1912, 
  still 
  virgin 
  forest, 
  the 
  bush 
  had 
  been 
  

   cut 
  down 
  to 
  supply 
  fuel 
  and 
  timber 
  to 
  a 
  considerable 
  extent 
  around 
  it, 
  and 
  conclusions, 
  

   therefore, 
  cannot 
  be 
  drawn 
  from 
  the 
  fact 
  that 
  the 
  fly 
  has 
  not 
  spread 
  widely 
  in 
  the 
  

   district. 
  It 
  may, 
  perhaps, 
  be 
  worth 
  noting 
  that, 
  in 
  spite 
  of 
  the 
  facts 
  mentioned 
  

   above, 
  there 
  have 
  always 
  been 
  channels 
  some 
  miles 
  in 
  breadth 
  along 
  which 
  the 
  pest 
  

   might 
  have 
  spread 
  without 
  encountering 
  any 
  modification 
  of 
  its 
  native 
  habitat 
  beyond 
  

   the 
  scarcity 
  of 
  game. 
  On 
  the 
  whole, 
  however, 
  it 
  seems 
  best 
  to 
  leave 
  this 
  side 
  of 
  the 
  

   matter 
  out 
  of 
  the 
  question. 
  It 
  should, 
  moreover, 
  be 
  noted 
  that 
  owing 
  to 
  the 
  large 
  

   number 
  of 
  cattle 
  used 
  for 
  transport 
  on 
  the 
  mines 
  and 
  farms, 
  our 
  information 
  concerning 
  

   the 
  range 
  of 
  the 
  pest 
  in 
  these 
  parts 
  is 
  exceedingly 
  good, 
  and 
  that 
  the 
  portion 
  of 
  the 
  

  

  