﻿98 
  RUPERT 
  W. 
  JACK 
  — 
  TSETSE 
  FLY 
  

  

  The 
  point 
  where 
  the 
  writer 
  carried 
  out 
  certain 
  investigations 
  on 
  this 
  watercourse 
  is 
  

   fifteen 
  miles 
  away 
  from 
  the 
  Hanyani, 
  the 
  nearest 
  open 
  water 
  at 
  the 
  end 
  of 
  the 
  dry 
  

   season. 
  The 
  grass 
  is 
  burnt 
  off 
  annually 
  by 
  the 
  natives, 
  and 
  the 
  game 
  naturally 
  

   forsakes 
  country 
  which 
  contains 
  neither 
  grass 
  nor 
  water. 
  Along 
  the 
  banks 
  of 
  the 
  

   Gorai, 
  nevertheless, 
  fly 
  is 
  abundant 
  in 
  October 
  and 
  November, 
  whilst 
  on 
  the 
  west 
  

   bank 
  of 
  the 
  Hanyani, 
  where 
  the 
  game 
  is 
  normally 
  abundant 
  at 
  this 
  time 
  of 
  year, 
  fly 
  

   is 
  scarce. 
  This 
  appears 
  at 
  first 
  sight 
  a 
  strong 
  argument 
  for 
  the 
  disassociation 
  of 
  

   tsetse 
  and 
  big 
  game, 
  but 
  closer 
  investigation 
  of 
  the 
  situation 
  reveals 
  the 
  presence 
  

   of 
  other 
  factors. 
  

  

  In 
  the 
  first 
  place, 
  the 
  situation 
  as 
  seen 
  in 
  October 
  and 
  November 
  is 
  only 
  tempo- 
  

   rary, 
  being 
  due 
  to 
  the 
  drying 
  up 
  of 
  the 
  rivers 
  and 
  the 
  burning 
  of 
  the 
  grass. 
  In 
  the 
  

   second 
  place, 
  although 
  at 
  the 
  time 
  of 
  the 
  visit 
  the 
  larger 
  antelopes 
  had 
  all 
  deserted 
  

   this 
  part 
  of 
  the 
  country, 
  there 
  were 
  left 
  behind 
  two 
  species 
  of 
  animals 
  undoubtedly 
  

   capable 
  of 
  yielding 
  sustenance 
  to 
  tsetse, 
  namely 
  warthog 
  and 
  duiker, 
  of 
  which 
  the 
  

   former 
  appears 
  to 
  the 
  writer 
  to 
  be 
  the 
  more 
  important, 
  from 
  the 
  fact 
  that 
  shot 
  

   specimens 
  are 
  frequently 
  found 
  abundantly 
  attended 
  by 
  the 
  fly, 
  and 
  that 
  trypano- 
  

   somes 
  have 
  been 
  found 
  in 
  warthog 
  blood 
  (Bevan, 
  inter 
  alios). 
  These 
  animals 
  either 
  

   have 
  the 
  power 
  of 
  burrowing 
  down 
  to 
  water 
  where 
  other 
  animals 
  would 
  have 
  to 
  

   thirst, 
  or 
  are 
  constitutionally 
  to 
  a 
  large 
  extent 
  independent 
  of 
  drinking, 
  because 
  

   they 
  are, 
  like 
  the 
  duiker, 
  met 
  with 
  in 
  very 
  dry 
  tracts 
  of 
  country 
  where 
  none 
  of 
  the 
  

   larger 
  antelopes 
  are 
  to 
  be 
  found. 
  Along 
  the 
  Gorai 
  Eiver, 
  in 
  November 
  1911, 
  the 
  

   writer 
  saw 
  several 
  herds 
  of 
  warthog, 
  and 
  one 
  herd 
  was 
  lying 
  on 
  the 
  very 
  river 
  bank 
  in 
  

   the 
  shade 
  where 
  the 
  tsetse 
  congregate, 
  and 
  was 
  probably 
  affording 
  a 
  meal 
  to 
  numerous 
  

   tsetse 
  at 
  the 
  time. 
  There 
  was 
  also 
  evidence 
  of 
  much 
  rooting 
  in 
  the 
  vicinity 
  of 
  the 
  

   river 
  where 
  the 
  ground 
  is 
  soft 
  and 
  succulent 
  roots 
  are 
  more 
  abundant 
  than 
  in 
  the 
  

   neighbouring 
  bush. 
  In 
  the 
  third 
  place, 
  the 
  fact 
  of 
  the 
  tsetse 
  not 
  being 
  found 
  associated 
  

   with 
  the 
  game 
  at 
  the 
  Hanyani 
  river 
  is 
  probably 
  accounted 
  for 
  by 
  the 
  nature 
  

   of 
  the 
  country. 
  Along 
  the 
  Hanyani 
  where 
  the 
  game 
  was 
  congregated 
  the 
  banks 
  of 
  

   the 
  river 
  are 
  very 
  thickly 
  wooded 
  and 
  there 
  is 
  much 
  very 
  dense 
  undergrowth, 
  whilst 
  

   this 
  condition 
  gives 
  way 
  to 
  country 
  in 
  which 
  shade 
  is 
  very 
  deficient. 
  Now 
  shade 
  

   is 
  essential 
  to 
  tsetse, 
  but 
  G. 
  morsitans 
  is 
  not, 
  in 
  the 
  writer's 
  experience, 
  found 
  in 
  

   abundance 
  in 
  this 
  territory 
  in 
  any 
  bush 
  so 
  tangled 
  as 
  to 
  be 
  difficult 
  of 
  penetration. 
  

   In 
  addition 
  to 
  this, 
  the 
  neighbouring 
  forest 
  is 
  unusually 
  open, 
  not 
  affording 
  much 
  

   shade 
  even 
  in 
  the 
  wet 
  season 
  when 
  tsetse 
  spreads 
  through 
  the 
  bush 
  instead 
  of 
  remain- 
  

   ing 
  confined 
  to 
  the 
  shady 
  banks 
  of 
  watercourses 
  and 
  edges 
  of 
  vleis. 
  The 
  Gorai 
  River 
  

   affords 
  excellent 
  winter 
  shade, 
  and 
  the 
  surrounding 
  bush 
  is 
  sufficiently 
  shady 
  during 
  

   the 
  rains, 
  so 
  that 
  it 
  is 
  in 
  all 
  respects 
  suitable 
  for 
  tsetse, 
  and 
  it 
  is 
  not 
  a 
  matter 
  for 
  

   wonder 
  that 
  the 
  fly 
  has 
  increased 
  and 
  made 
  its 
  home 
  in 
  this 
  part, 
  whilst 
  it 
  has 
  failed 
  

   to 
  do 
  so 
  to 
  the 
  same 
  extent 
  on 
  that 
  part 
  of 
  the 
  Hanyani 
  river 
  to 
  which 
  reference 
  has 
  

   been 
  made. 
  In 
  April 
  1911, 
  the 
  writer 
  again 
  visited 
  the 
  neighbourhood 
  of 
  the 
  Gorai 
  

   River 
  and 
  found 
  that 
  game, 
  including 
  rhinoceros, 
  zebra, 
  sable, 
  kudu, 
  eland, 
  impala, 
  

   etc., 
  was 
  moderately 
  abundant 
  in 
  the 
  haunts 
  of 
  the 
  tsetse, 
  which 
  was 
  at 
  that 
  time 
  

   to 
  be 
  met 
  with 
  throughout 
  the 
  bush. 
  

  

  The 
  foregoing 
  argument 
  has 
  been 
  set 
  out 
  in 
  some 
  detail 
  in 
  an 
  endeavour 
  to 
  demon- 
  

   state 
  that 
  opinions 
  formed 
  in 
  passing 
  through 
  a 
  certain 
  locality 
  at 
  one 
  season 
  of 
  

   the 
  year 
  are 
  liable 
  to 
  serious 
  error, 
  and 
  that 
  too 
  much 
  weight 
  should 
  not 
  therefore 
  

  

  