﻿INVESTIGATIONS 
  INTO 
  THE 
  BIONOMICS 
  OF 
  GLOSSINA 
  PALPALIS. 
  381 
  

  

  It 
  will 
  be 
  seen 
  that 
  of 
  the 
  eight 
  islands 
  listed, 
  two 
  differed 
  from 
  the 
  rest 
  in 
  being 
  

   infested 
  in 
  the 
  interior. 
  One 
  of 
  these, 
  Damba, 
  is 
  flat, 
  with 
  streams 
  and 
  marshes 
  

   in 
  its 
  interior, 
  and 
  with 
  a 
  dense 
  infestation 
  of 
  fly 
  along 
  shore. 
  Two 
  others 
  — 
  Bugaba 
  

   and 
  Kome 
  — 
  also 
  had 
  streams 
  flowing 
  down 
  from 
  the 
  hills, 
  but 
  they 
  were 
  hilly 
  and 
  

   the 
  infestation 
  along 
  shore 
  was 
  light. 
  Either 
  elevation 
  or 
  lightness 
  of 
  infestation 
  

   along 
  shore 
  might 
  be 
  a 
  possible 
  explanation 
  for 
  absence 
  of 
  fly 
  inland, 
  and 
  its 
  

   absence 
  is 
  merely 
  negative 
  evidence 
  that 
  it 
  does 
  not 
  always 
  occur 
  in 
  humid 
  localities 
  

   near 
  lake 
  shore 
  colonies. 
  

  

  But 
  in 
  the 
  case 
  of 
  Bukassa 
  Island 
  we 
  have 
  a 
  dry, 
  hilly 
  interior, 
  with 
  only 
  a 
  light 
  

   infestation 
  along 
  shore, 
  and 
  for 
  all 
  this 
  a 
  general 
  infestation 
  of 
  the 
  interior. 
  This 
  

   is 
  not 
  negative, 
  but 
  is 
  absolutely 
  positive 
  and 
  very 
  strong 
  evidence 
  that, 
  whatever 
  

   it 
  may 
  be 
  which 
  restricts 
  the 
  range 
  of 
  this 
  tsetse 
  to 
  a 
  narrow 
  belt 
  along 
  the 
  shore 
  

   of 
  the 
  islands 
  generally, 
  it 
  is 
  not 
  the 
  presence 
  of 
  water 
  or 
  soil 
  humidity, 
  for 
  the 
  interior 
  

   of 
  Bukassa 
  is, 
  perhaps, 
  the 
  driest 
  and 
  hilliest 
  of 
  any 
  of 
  those 
  listed 
  except 
  Wema. 
  

   And 
  whereas 
  it 
  is 
  perfectly 
  possible 
  that 
  the 
  presence 
  of 
  open 
  water 
  might 
  account 
  

   for 
  infestation 
  by 
  tsetse 
  of 
  a 
  belt 
  several 
  miles 
  in 
  width 
  along 
  the 
  borders 
  of 
  it, 
  it 
  is 
  

   impossible 
  to 
  consider 
  water 
  alone 
  as 
  the 
  determining 
  factor 
  when, 
  on 
  some 
  islands 
  

   the 
  inland 
  range 
  of 
  fly 
  is 
  virtually 
  limited 
  to 
  500 
  yards 
  or 
  less, 
  whereas 
  on 
  others 
  it 
  

   is 
  extended 
  to 
  1,500 
  yards 
  and 
  more, 
  and 
  with 
  no 
  surface 
  water 
  in 
  sight. 
  

  

  Slight 
  though 
  this 
  evidence 
  is, 
  it 
  is 
  of 
  such 
  a 
  positive 
  character 
  that 
  it 
  is 
  practically 
  

   conclusive. 
  Some 
  other 
  factor 
  than 
  open 
  water 
  must 
  be 
  held 
  accountable 
  for 
  

   limitation 
  to 
  inland 
  range 
  of 
  Glossina 
  palpalis 
  from 
  shores 
  of 
  lakes 
  or 
  banks 
  of 
  streams. 
  

  

  V 
  (c). 
  Effect 
  of 
  Food 
  Supply 
  on 
  Range 
  of 
  the 
  Fly. 
  

  

  A 
  comparison 
  between 
  the 
  two 
  islands, 
  Bukassa 
  and 
  Damba, 
  in 
  search 
  of 
  points 
  

   of 
  similarity, 
  which 
  should 
  at 
  the 
  same 
  time 
  be 
  points 
  of 
  difference 
  between 
  these 
  

   and 
  the 
  other 
  islands 
  named 
  in 
  Table 
  XVII, 
  led 
  to 
  the 
  conclusion 
  that 
  the 
  most 
  

   probable 
  explanation 
  for 
  their 
  infestation 
  interiorly 
  by 
  tsetse 
  was 
  the 
  presence 
  of 
  

   unusually 
  large 
  numbers 
  of 
  game 
  animals 
  : 
  of 
  situtunga 
  on 
  Damba, 
  and 
  of 
  domestic 
  

   pigs 
  run 
  wild 
  on 
  Bukassa. 
  This 
  conclusion 
  was 
  reached 
  reluctantly, 
  because 
  at 
  that 
  

   time 
  (September 
  1918) 
  it 
  was 
  believed 
  that 
  the 
  only 
  favoured 
  hosts 
  of 
  this 
  species, 
  

   of 
  tsetse 
  were 
  reptilian. 
  

  

  The 
  course 
  of 
  the 
  fly 
  survey 
  of 
  the 
  islands 
  was 
  thereupon 
  set 
  to 
  include 
  careful 
  

   study 
  of 
  conditions 
  on 
  all 
  such 
  as 
  were 
  known 
  or 
  suspected 
  to 
  be 
  more 
  than 
  usually 
  

   well 
  stocked 
  with 
  game. 
  These 
  included 
  specifically 
  the 
  group 
  of 
  semi 
  detached 
  

   islands 
  of 
  Bukone, 
  Serina 
  and 
  Lulamba, 
  and 
  the 
  island 
  of 
  Buvu, 
  upon 
  which 
  

   pigs 
  were 
  known 
  to 
  occur, 
  and 
  the 
  (relatively) 
  very 
  large 
  island 
  of 
  Sesse 
  (Bugalla- 
  

   Buninga), 
  which 
  had 
  been 
  reported 
  to 
  be 
  overrun 
  with 
  situtunga. 
  

  

  Examination 
  of 
  the 
  pig 
  islands 
  disclosed 
  the 
  fact 
  that 
  though 
  great 
  numbers 
  

   of 
  the 
  animals 
  had 
  been 
  present 
  (enough 
  to 
  cover 
  them 
  with 
  networks 
  of 
  trails 
  

   and 
  to 
  uproot 
  the 
  soil 
  nearly 
  everywhere 
  in 
  the 
  woodland) 
  some 
  great 
  catastrophe 
  

   had 
  reduced 
  their 
  numbers 
  to 
  a 
  few 
  stragglers. 
  More 
  skeletons 
  were 
  found 
  than 
  

   traces 
  of 
  living 
  animals. 
  But 
  one 
  result 
  of 
  the 
  visit 
  was 
  to 
  discover 
  a 
  " 
  following 
  

   swarm 
  ' 
  : 
  of 
  fly 
  about 
  a 
  pig 
  that 
  was 
  shot, 
  and 
  to 
  prove 
  conclusively 
  enough 
  that 
  

   this 
  animal 
  may 
  be 
  a 
  favoured 
  host. 
  None 
  of 
  the 
  islands 
  was 
  found 
  to 
  be 
  infested 
  

   by 
  fly 
  except 
  very 
  narrowly 
  along 
  the 
  lake 
  shore. 
  

   (659) 
  c2. 
  

  

  