﻿71 
  

  

  TSETSE 
  FLY 
  IN 
  SOUTHERN 
  RHODESIA, 
  1918. 
  

  

  By 
  Rupert 
  W. 
  Jack, 
  F.E.S., 
  

  

  Entomologist, 
  Department 
  of 
  Agriculture, 
  Rhodesia. 
  

   (Plates 
  II-IV, 
  Maps 
  I-III.) 
  

  

  The 
  history 
  of 
  tsetse-fly 
  in 
  Southern 
  Rhodesia 
  up 
  to 
  the 
  present 
  year 
  (1918) 
  con- 
  

   tinues 
  on 
  the 
  whole 
  to 
  be 
  one 
  of 
  expansion, 
  although 
  on 
  the 
  other 
  hand 
  one 
  small, 
  

   but 
  important, 
  belt 
  appears 
  to 
  have 
  become 
  extinct. 
  In 
  addition, 
  a 
  fly 
  area 
  in 
  the 
  

   Mocambique 
  Company's 
  territory 
  has 
  extended 
  up 
  to 
  our 
  eastern 
  border, 
  with 
  the 
  

   result 
  that 
  serious 
  losses 
  of 
  cattle 
  from 
  trypanosomiasis 
  have 
  occurred 
  on 
  the 
  farms 
  

   in 
  that 
  region. 
  Detailed 
  reports 
  on 
  the 
  advance 
  or 
  retrogression 
  of 
  Glossina 
  morsitans 
  

   in 
  other 
  parts 
  of 
  Africa 
  appear 
  to 
  be 
  lacking, 
  and 
  it 
  is 
  felt 
  that 
  in 
  view 
  of 
  the 
  position 
  

   of 
  this 
  territory 
  in 
  relation 
  to 
  tsetse-fly 
  a 
  review 
  of 
  the 
  situation 
  to 
  the 
  present 
  day 
  

   may 
  not 
  be 
  without 
  general 
  interest. 
  

  

  The 
  " 
  fly 
  areas 
  " 
  in 
  Southern 
  Rhodesia 
  may 
  be 
  referred 
  to 
  as 
  follows 
  : 
  — 
  

   (1) 
  Sebungwe 
  Belt, 
  occupying 
  the 
  greater 
  portion 
  of 
  the 
  western 
  half 
  of 
  the 
  Sebungwe 
  

   district 
  ; 
  (2) 
  Umniati 
  Belt, 
  lying 
  astride 
  the 
  Umniati 
  river, 
  partly 
  in 
  the 
  Hartley 
  

   and 
  partly 
  in 
  the 
  Sebungwe 
  districts 
  ; 
  (3) 
  Northern 
  Belt, 
  occupying 
  the 
  greater 
  part 
  

   of 
  the 
  country 
  between 
  the 
  escarpment 
  and 
  the 
  Zambesi 
  River 
  in 
  the 
  northern 
  

   portion 
  of 
  the 
  Lomagundi 
  district, 
  and 
  extending 
  eastward 
  into 
  the 
  Darwin 
  district 
  ; 
  

  

  (4) 
  Jetjenini 
  Belt, 
  in 
  the 
  neighbourhood 
  of 
  Jetjenini 
  Mountain, 
  Lomagundi 
  district 
  ; 
  

  

  (5) 
  Suri-suri 
  Belt, 
  in 
  the 
  vicinity 
  of 
  the 
  Suri-suri 
  river, 
  between 
  Hartley 
  and 
  Gatooma, 
  

   in 
  the 
  Hartley 
  district 
  ; 
  (6) 
  Melsetter 
  Border 
  Belt, 
  lying 
  almost 
  entirely 
  in 
  Portuguese 
  

   East 
  Africa, 
  but 
  affecting 
  certain 
  farms 
  on 
  the 
  eastern 
  border 
  of 
  the 
  Melsetter 
  district. 
  

  

  (1) 
  Sebungwe 
  Belt. 
  Owing 
  to 
  its 
  extent 
  and 
  the 
  fact 
  that 
  sleeping 
  sickness 
  is 
  

   endemic 
  in 
  a 
  certain 
  portion 
  of 
  it, 
  this 
  is 
  at 
  present 
  the 
  most 
  important 
  fly-area 
  in 
  

   the 
  territory. 
  The 
  extension 
  of 
  the 
  infested 
  country 
  since 
  it 
  shrank 
  to 
  insignificant 
  

   proportions 
  in 
  1896-7 
  until 
  the 
  year 
  1913 
  has 
  been 
  described 
  in 
  a 
  previous 
  paper.* 
  

   During 
  the 
  past 
  five 
  years 
  this 
  progress 
  has 
  been 
  continued 
  and 
  the 
  new 
  country 
  

   involved 
  is 
  shown 
  in 
  Map 
  1. 
  The 
  present 
  area 
  of 
  this 
  belt 
  is 
  estimated 
  at 
  about 
  4,500 
  

   square 
  miles. 
  

  

  The 
  value 
  of 
  careful 
  notes 
  on 
  the 
  channels 
  along 
  which 
  the 
  fly 
  has 
  spread 
  lies 
  chiefly 
  

   in 
  the 
  accumulation 
  of 
  information 
  concerning 
  factors 
  which 
  favour 
  the 
  pest. 
  It 
  

   is 
  unfortunate 
  that 
  circumstances 
  have 
  not 
  permitted 
  of 
  more 
  detailed 
  work 
  in 
  this 
  

   connection, 
  but 
  such 
  observations 
  as 
  have 
  been 
  made 
  were 
  carried 
  out 
  with 
  this 
  

   express 
  object 
  in 
  view. 
  The 
  practical 
  point 
  lies 
  in 
  the 
  possibility 
  of 
  rendering 
  

   threatened 
  areas 
  unsuited 
  to 
  the 
  pest 
  or 
  of 
  interposing 
  a 
  barrier 
  and 
  thus 
  checking 
  

   the 
  further 
  extension 
  of 
  the 
  belt. 
  

  

  Broadly 
  speaking, 
  the 
  contentions 
  of 
  the 
  early 
  hunters 
  concerning 
  the 
  association 
  

   G. 
  morsitans 
  with 
  big 
  game 
  are 
  fully 
  supported 
  in 
  this 
  area, 
  although 
  this 
  is 
  not 
  in- 
  

   variably 
  the 
  case 
  elsewhere. 
  The 
  increase 
  of 
  the 
  fly 
  and 
  the 
  extension 
  of 
  its 
  bound- 
  

   aries 
  have 
  corresponded 
  with 
  a 
  notable 
  increase 
  of 
  the 
  larger 
  antelopes, 
  and 
  to 
  a 
  less 
  

   extent 
  of 
  buffalo. 
  The 
  new 
  territory 
  occupied 
  by 
  the 
  fly 
  is 
  all 
  game 
  country. 
  The 
  

   most 
  rapid 
  extension 
  has 
  taken 
  place 
  through 
  country 
  where 
  game 
  abounds 
  ; 
  fly 
  is 
  

  

  *Bull. 
  Ent. 
  Res. 
  v, 
  Sept. 
  1914, 
  pp. 
  97-110. 
  

  

  