﻿430 
  W. 
  F. 
  FISKE. 
  

  

  The 
  first, 
  at 
  Crocodile 
  Point, 
  lies 
  from 
  to 
  400 
  yards 
  from 
  massive 
  shelter 
  on 
  

   Bulago 
  Island. 
  Infestation 
  was 
  : 
  — 
  

  

  Crocodile 
  Point 
  (Jan. 
  1914) 
  : 
  male 
  density 
  22*7 
  ; 
  female 
  percentage 
  42*9. 
  

   Near 
  massive 
  shelter 
  on 
  south 
  shore 
  of 
  island 
  : 
  male 
  density 
  20*4 
  ; 
  female 
  

   percentage 
  40*6. 
  

   The 
  second 
  area 
  of 
  light 
  shelter 
  and 
  breeding 
  ground 
  was 
  on 
  an 
  islet 
  south 
  of 
  

   Dziru, 
  and 
  separated 
  from 
  massive 
  shelter 
  by 
  an 
  open 
  channel 
  of 
  about 
  100 
  yards 
  

   in 
  width. 
  This 
  served 
  as 
  a 
  serious 
  obstruction 
  in 
  free 
  movement 
  of 
  fly. 
  Infestation 
  

   in 
  March 
  1915 
  was 
  : 
  — 
  

  

  Islet 
  : 
  male 
  density 
  3*8 
  ; 
  female 
  percentage 
  26*6. 
  Island 
  : 
  male 
  density 
  5*0 
  ; 
  

   female 
  percentage 
  44*4. 
  

   In 
  September 
  1914 
  infestation 
  at 
  these 
  same 
  points 
  had 
  been 
  : 
  — 
  

  

  Islet: 
  male 
  density 
  1*5; 
  female 
  percentage 
  0. 
  Island: 
  male 
  density 
  6*5; 
  

   female 
  percentage 
  13*3. 
  

   The 
  third 
  area 
  is 
  the 
  islet 
  of 
  Kukassu, 
  which 
  is 
  more 
  than 
  600 
  yards 
  off 
  the 
  shore 
  

   of 
  Bubambe 
  Island, 
  which 
  is 
  the 
  nearest 
  massive 
  shelter. 
  This 
  width 
  of 
  the 
  channel 
  

   is 
  a 
  complete 
  obstruction 
  to 
  movement 
  of 
  fly. 
  In 
  consequence, 
  infestation, 
  in 
  

   August 
  1914, 
  was 
  found 
  to 
  be 
  : 
  — 
  

   Kukassu 
  Islet 
  : 
  nil. 
  

  

  Bubambe 
  Island 
  (at 
  point 
  opposite) 
  : 
  male 
  density 
  13*7 
  ; 
  female 
  percentage 
  7*8. 
  

   These 
  and 
  other 
  data 
  of 
  a 
  similar 
  character 
  provided 
  a 
  weight 
  of 
  evidence 
  that 
  

   was 
  in 
  the 
  end 
  conclusive 
  ; 
  lightly 
  sheltered 
  areas 
  may 
  provide 
  the 
  best 
  and 
  most 
  

   attractive 
  hunting, 
  breeding 
  and 
  assembling 
  grounds 
  for 
  Glossina 
  palpalis, 
  but 
  

   unless 
  they 
  lie 
  within 
  easy 
  range 
  or 
  reach 
  of 
  the 
  flies 
  from 
  massive 
  shelter 
  they 
  

   will 
  not 
  be 
  infested. 
  If 
  there 
  is 
  no 
  obstacle 
  to 
  free 
  movement 
  of 
  flies 
  between 
  such 
  

   areas 
  and 
  massively 
  sheltered 
  areas, 
  they 
  are 
  apt 
  to 
  be 
  more 
  densely 
  infested 
  than 
  

   the 
  other. 
  But 
  as 
  distance 
  or 
  obstacles 
  to 
  free 
  movement 
  increase, 
  infestation 
  

   diminishes, 
  until 
  finally 
  beyond 
  certain 
  limits 
  they 
  cease 
  to 
  be 
  infested. 
  

  

  VIII 
  (b). 
  Correlation 
  between 
  Type 
  of 
  Shelter 
  and 
  Density 
  of 
  Fly 
  as 
  disclosed 
  

   by 
  Survey 
  of 
  large 
  Islands 
  and 
  Mainland. 
  

  

  In 
  the 
  beginning 
  it 
  was 
  expected 
  that 
  the 
  survey 
  of 
  small 
  islands 
  and 
  comparisons 
  

   between 
  them 
  with 
  respect 
  to 
  environmental 
  conditions 
  and 
  density 
  of 
  infestation 
  

   would 
  be 
  productive 
  of 
  the 
  most 
  valuable 
  data. 
  But 
  it 
  was 
  discovered 
  that 
  insularity, 
  

   as 
  it 
  affected 
  the 
  normal 
  dispersion 
  of 
  fly 
  (p. 
  425), 
  was 
  so 
  confusing 
  a 
  factor 
  that 
  the 
  

   data 
  secured 
  through 
  the 
  survey 
  of 
  long 
  reaches 
  of 
  shore 
  on 
  the 
  mainland 
  and 
  large 
  

   islands 
  were 
  much 
  more 
  satisfactory. 
  

  

  Especially 
  is 
  this 
  true 
  where 
  the 
  survey 
  reveals, 
  as 
  on 
  Bugaba 
  Island 
  (fig. 
  7, 
  p. 
  423), 
  

   in 
  the 
  Bwendi 
  District 
  (fig. 
  6, 
  p. 
  411)., 
  at 
  Dumo 
  Point 
  and 
  Mujuzi 
  Creek 
  (fig. 
  5, 
  

   p. 
  388), 
  etc., 
  the 
  existence 
  of 
  well 
  defined, 
  isolated 
  or 
  semi-isolated 
  colonies 
  of 
  fly, 
  

   each 
  with 
  a 
  sharply 
  defined 
  nucleus, 
  from 
  which 
  flies 
  are 
  continually 
  dispersing 
  to 
  

   infest 
  a 
  zone 
  surrounding. 
  

  

  The 
  most 
  interesting 
  of 
  all 
  the 
  colonies 
  encountered 
  in 
  the 
  fly 
  survey 
  was 
  certainly 
  

   that 
  at 
  Mujuzi 
  Creek, 
  ot 
  wnich 
  so 
  much 
  has 
  been 
  written, 
  and 
  which 
  centres 
  at 
  a 
  

   point 
  where 
  food 
  is 
  provided 
  in 
  a 
  region 
  that 
  is 
  deficient 
  in 
  food. 
  The 
  second 
  in 
  

  

  