﻿384 
  

  

  W. 
  B. 
  JOHNSON 
  AND 
  LLEWELLYN 
  LLOYD. 
  

  

  mammalian, 
  and 
  47 
  per 
  cent, 
  contained 
  only 
  the 
  merest 
  trace 
  of 
  detritus 
  ; 
  the 
  

   flies 
  were 
  well 
  nourished 
  and 
  showed 
  a 
  great 
  development 
  of 
  fat 
  ; 
  the 
  female 
  per- 
  

   centage 
  was 
  16-6, 
  indicating 
  no 
  particular 
  hunger 
  in 
  the 
  fly. 
  This 
  forms 
  an 
  instance 
  

   where 
  the 
  two 
  species 
  have 
  access 
  to 
  the 
  same 
  food 
  supply 
  at 
  a 
  time 
  when 
  the 
  grass 
  

   is 
  long 
  and 
  green, 
  and 
  the 
  advantage 
  is 
  decidedly 
  with 
  morsitans. 
  

  

  The 
  second 
  instance 
  was 
  at 
  Dau 
  (Gombe 
  Division) 
  towards 
  the 
  end 
  of 
  the 
  dry 
  

   season 
  in 
  March. 
  This 
  fly 
  area 
  is 
  a 
  wide 
  flat 
  valley 
  with 
  type 
  (b) 
  forest, 
  very 
  small 
  

   permanent 
  pools 
  and 
  open 
  spaces. 
  Large 
  and 
  small 
  antelopes 
  and 
  pig 
  were 
  plentiful 
  

   in 
  the 
  district, 
  which 
  was 
  a 
  good 
  deal 
  hunted 
  by 
  the 
  natives. 
  Baboons 
  were 
  very 
  

   numerous. 
  It 
  is 
  improbable 
  that 
  the 
  water 
  Varanus 
  was 
  present, 
  crocodiles 
  certainly 
  

   were 
  not. 
  There 
  was 
  a 
  farm 
  close, 
  by, 
  but 
  it 
  was 
  temporarily 
  deserted, 
  as 
  the 
  crops 
  

   were 
  all 
  gathered 
  and 
  removed. 
  The 
  sporadic 
  visits 
  of 
  the 
  hunters 
  gave 
  the 
  only 
  

   chance 
  of 
  human 
  blood, 
  and 
  there 
  were 
  no 
  domestic 
  animals. 
  A 
  severe 
  fire 
  had 
  

   just 
  passed 
  through 
  and 
  the 
  cover 
  of 
  the 
  game 
  had 
  been 
  largely 
  destroyed. 
  The 
  

   antelopes 
  seemed 
  to 
  be 
  feeding 
  on 
  the 
  higher 
  ground, 
  where 
  there 
  was 
  much 
  spoor, 
  

   and 
  passing 
  through 
  the 
  valley, 
  its 
  normal 
  abode, 
  only 
  at 
  night, 
  but 
  the 
  tsetse 
  

   remained 
  in 
  the 
  shady 
  valley. 
  The 
  baboons 
  were 
  there 
  all 
  day. 
  We 
  caught 
  177 
  

   tachinoides 
  and 
  80 
  were 
  dissected 
  ; 
  of 
  these 
  7 
  contained 
  recognisable 
  blood, 
  all 
  

   mammalian, 
  while 
  only 
  36 
  per 
  cent, 
  of 
  them 
  contained 
  a 
  small 
  quantity 
  of 
  detritus 
  ; 
  

   they 
  were 
  well 
  nourished 
  and 
  showed 
  a 
  good 
  development 
  of 
  fat. 
  Of 
  149 
  morsitans 
  

   obtained, 
  71 
  were 
  dissected 
  ; 
  of 
  these 
  6 
  contained 
  recognisable 
  blood, 
  all 
  mammalian, 
  

   while 
  57 
  per 
  cent, 
  of 
  them 
  contained 
  only 
  a 
  small 
  quantity 
  of 
  detritus 
  ; 
  they 
  were 
  

   thin 
  and 
  showed 
  little 
  development 
  of 
  fat 
  ; 
  the 
  female 
  percentage 
  was 
  43-6, 
  indi- 
  

   cating 
  hunger. 
  In 
  this 
  case 
  it 
  seemed 
  to 
  us 
  certain 
  that 
  tachinoides 
  was 
  feeding 
  on 
  

   the 
  baboons 
  to 
  an 
  extent 
  that 
  the 
  less 
  agile 
  morsitans 
  was 
  unable 
  to 
  do 
  and 
  that 
  

   the 
  latter, 
  deprived 
  of 
  its 
  normal 
  food 
  temporarily, 
  was 
  consequently 
  starved. 
  

  

  A 
  further 
  contrast 
  between 
  the 
  food 
  of 
  these 
  two 
  flies 
  was 
  brought 
  out 
  in 
  the 
  

   dissections. 
  Notes 
  were 
  kept 
  as 
  to 
  whether 
  the 
  recognisable 
  mammalian 
  blood 
  

   contained 
  the 
  small 
  red 
  cells, 
  such 
  as 
  occur 
  in 
  the 
  blood 
  of 
  most 
  antelopes, 
  cattle, 
  

   sheep 
  and 
  goats, 
  or 
  the 
  large 
  type 
  of 
  red 
  cell 
  which 
  occurs 
  in 
  man 
  and 
  most 
  other 
  

   mammals. 
  No 
  measurements 
  were 
  made, 
  as 
  the 
  task 
  would 
  have 
  been 
  too 
  great, 
  

   but 
  a 
  constant 
  picture 
  of 
  the 
  difference 
  in 
  size 
  was 
  before 
  the 
  eye 
  owing 
  to 
  the 
  

   frequent 
  occurrence 
  of 
  both 
  types. 
  The 
  figures 
  are 
  given 
  in 
  Table 
  II 
  and 
  show 
  

   that 
  the 
  large 
  type 
  of 
  red 
  cell 
  was 
  found 
  twice 
  as 
  frequently 
  in 
  tachinoides 
  as 
  in 
  

   morsitans, 
  and 
  the 
  small 
  type 
  occurred 
  five 
  times 
  as 
  frequently 
  in 
  the 
  latter 
  as 
  in 
  

   the 
  former. 
  This 
  further 
  shows 
  that 
  tachinoides 
  is 
  less 
  closely 
  associated 
  with 
  the 
  

   antelope 
  class 
  than 
  is 
  morsitans, 
  and 
  other 
  evidence 
  of 
  this 
  is 
  given 
  later 
  (page 
  390). 
  

  

  TABLE 
  II. 
  

  

  Contrasting 
  the 
  Type 
  of 
  Mammalian 
  Blood 
  found 
  in 
  Flies 
  dissected, 
  and 
  the 
  Proportion 
  infected 
  

  

  with 
  Flagellates. 
  

  

  Species. 
  

  

  Number 
  

  

  of 
  

  

  flies 
  

  

  examined. 
  

  

  Number 
  

  

  with 
  

  

  recognisable 
  

  

  mammalian 
  

  

  blood. 
  

  

  Percentage 
  containing 
  red 
  cells 
  of 
  

  

  Large 
  

   type- 
  

  

  Small 
  

   type. 
  

  

  Indeter- 
  

   minate 
  type. 
  

  

  Percentage 
  

   of 
  total 
  

  

  flies 
  

  

  infected 
  

  

  with 
  

  

  flagellates. 
  

  

  G. 
  morsitans 
  

   G. 
  tachinoides 
  

   G. 
  palpalis 
  

  

  500 
  

  

  1,500 
  

  

  552 
  

  

  93 
  

  

  195 
  

  

  75 
  

  

  42-0 
  

   85-0 
  

   55-0 
  

  

  56-0 
  

   11-0 
  

   25-0 
  

  

  2-0 
  

  

  4-0 
  

  

  20-0* 
  

  

  26-4 
  

  

  11-3 
  

  

  5-6 
  

  

  * 
  From 
  early 
  figures 
  — 
  probably 
  mostly 
  large 
  type. 
  

  

  