﻿TSETSE 
  FLY 
  IN 
  SOUTHERN 
  RHODESIA, 
  1918. 
  87 
  

  

  With 
  regard 
  to 
  the 
  possibilities 
  of 
  an 
  extensive 
  reptilian 
  diet, 
  the 
  larger 
  reptiles 
  

   are 
  very 
  scarce 
  in 
  most 
  morsitans 
  areas, 
  and 
  those 
  that 
  depend 
  upon 
  water 
  are 
  fre- 
  

   quently 
  altogether 
  absent. 
  A 
  reptilian 
  diet 
  in 
  many 
  areas 
  would 
  necessarily 
  be 
  

   confined 
  to 
  small 
  active 
  lizards 
  and 
  chameleons. 
  There 
  is 
  no 
  evidence 
  to 
  suggest 
  

   . 
  that 
  the 
  former 
  would 
  allow 
  themselves 
  to 
  be 
  fed 
  upon 
  to 
  any 
  extent, 
  but 
  chameleons 
  

   are 
  no 
  doubt 
  an 
  occasional 
  source 
  of 
  sustenance. 
  Where 
  the 
  fly 
  occurs 
  along 
  the 
  

   banks 
  of 
  a 
  fairly 
  large 
  river, 
  however, 
  there 
  would 
  appear 
  to 
  be 
  no 
  obvious 
  reason 
  

   why 
  the 
  same 
  food-supply 
  as 
  that 
  which 
  serves 
  palpalis 
  should 
  not 
  suffice. 
  G. 
  mor- 
  

   sitans, 
  however, 
  not 
  only 
  shows 
  no 
  predilection 
  for 
  such 
  situations, 
  but 
  appears 
  

   largely 
  to 
  avoid 
  them. 
  In 
  the 
  portion 
  of 
  the 
  Umniati 
  area 
  already 
  referred 
  to, 
  fly 
  is 
  

   certainly 
  to 
  be 
  met 
  with 
  on 
  the 
  banks 
  of 
  the 
  river 
  itself, 
  but 
  is 
  far 
  more 
  abundant 
  in 
  

   the 
  adjacent 
  forest. 
  Its 
  distribution 
  therefore 
  does 
  not 
  suggest 
  a 
  dependence 
  on 
  

   water-loving 
  reptiles 
  or 
  amphibia. 
  The 
  pest 
  actually 
  lives 
  in 
  the 
  old 
  game 
  haunts, 
  

   now 
  greatly 
  depleted, 
  but 
  its 
  habitat 
  is 
  constantly 
  crossed 
  by 
  large 
  troops 
  of 
  baboons 
  

   moving 
  to 
  and 
  from 
  the 
  river, 
  and 
  the 
  paths 
  of 
  these 
  animals 
  are 
  quite 
  a 
  conspicuous 
  

   feature 
  in 
  this 
  locality. 
  Whatever 
  diet 
  is 
  serving 
  the 
  fly 
  along 
  this 
  stretch, 
  however, 
  

   it 
  does 
  not 
  appear 
  to 
  produce 
  the 
  same 
  increase 
  in 
  the 
  pest 
  as 
  an 
  abundance 
  of 
  game, 
  

   as 
  is 
  shown 
  by 
  the 
  lack 
  of 
  tendency 
  to 
  expansion 
  since 
  the 
  reduction 
  of 
  the 
  latter. 
  

  

  (4) 
  The 
  fact 
  that 
  fluctuations 
  in 
  the 
  distribution 
  of 
  morsitans 
  occurred 
  previous 
  

   to 
  any 
  wholesale 
  reduction 
  of 
  game 
  has 
  really 
  little 
  bearing 
  on 
  the 
  controversy, 
  as 
  

   nothing 
  comparable 
  with 
  the 
  phenomena 
  which 
  accompanied 
  game 
  reduction 
  

   either 
  locally 
  or 
  over 
  a 
  vast 
  area 
  is 
  on 
  record. 
  It 
  would 
  be 
  curious 
  if 
  tsetse-fly 
  were 
  

   not 
  subject, 
  at 
  least 
  in 
  some 
  degree, 
  to 
  similar 
  influences 
  to 
  those 
  which 
  induce 
  

   enormous 
  fluctuations 
  in 
  the 
  occurrence 
  of 
  many 
  other 
  insects, 
  such 
  as 
  excessive 
  

   multiplication 
  of 
  parasites 
  and 
  other 
  enemies 
  in 
  a 
  given 
  area. 
  Glossina, 
  on 
  account 
  

   of 
  its 
  slow 
  rate 
  of 
  reproduction, 
  has 
  less 
  ability 
  for 
  recovery 
  than 
  the 
  vast 
  majority 
  

   of 
  other 
  insects 
  and 
  so 
  must 
  be 
  more 
  liable 
  to 
  die 
  out 
  entirely 
  under 
  persecution. 
  

  

  To 
  sum 
  up, 
  the 
  case 
  for 
  the 
  vital 
  association 
  of 
  G. 
  morsitans 
  with 
  the 
  larger 
  mammals 
  

   appears 
  to 
  the 
  writer 
  to 
  be 
  extremely 
  strong, 
  in 
  South 
  Africa 
  at 
  least, 
  and 
  the 
  evi- 
  

   dence 
  brought 
  forward 
  in 
  opposition 
  comparatively 
  insignificant. 
  There 
  appears 
  

   to 
  be 
  no 
  direct 
  evidence 
  at 
  all 
  that 
  morsitans 
  feeds 
  to 
  any 
  great 
  extent 
  on 
  the 
  smaller 
  

   mammals 
  under 
  natural 
  conditions, 
  and 
  the 
  failure 
  to 
  find 
  trypanosomes 
  in 
  the 
  blood 
  

   of 
  such 
  mammals 
  by 
  Montgomery 
  and 
  Kinghorn, 
  and 
  the 
  Royal 
  Commission 
  in 
  

   Nyasaland, 
  constitutes 
  distinct 
  evidence 
  to 
  the 
  contrary. 
  Whatever 
  may 
  be 
  the 
  truth 
  

   concerning 
  the 
  vital 
  dependence 
  of 
  morsitans 
  on 
  the 
  larger 
  mammals 
  in 
  all 
  areas, 
  

   there 
  is 
  every 
  reason 
  to 
  believe 
  that 
  the 
  pest 
  feeds 
  upon 
  them 
  by 
  preference 
  and 
  

   thrives 
  best 
  in 
  their 
  presence, 
  and 
  apart 
  from 
  any 
  other 
  consideration 
  this 
  constitutes 
  

   a 
  powerful 
  argument 
  for 
  the 
  suppression 
  of 
  the 
  larger 
  game 
  animals, 
  which 
  are, 
  in 
  

   any 
  case, 
  bad 
  neighbours 
  to 
  farmers 
  and 
  stockowners. 
  The 
  writer 
  yields 
  to 
  none 
  

   in 
  his 
  love 
  of 
  wild 
  life, 
  but 
  when 
  it 
  comes 
  to 
  a 
  choice 
  between 
  developing 
  colonial 
  

   territory 
  economically 
  or 
  maintaining 
  it 
  as 
  a 
  zoological 
  garden, 
  there 
  can 
  only 
  be 
  one 
  

   decision. 
  

  

  Explanation 
  of 
  Fly-belts. 
  

  

  Austen 
  on 
  page 
  4 
  of 
  his 
  " 
  Handbook 
  of 
  the 
  Tsetse 
  Flies 
  ' 
  sums 
  up 
  the 
  

   question 
  of 
  fly 
  belts 
  as 
  follows 
  ; 
  — 
  " 
  We 
  are 
  still 
  somewhat 
  in 
  the 
  dark 
  as 
  to 
  

  

  