﻿396 
  W. 
  B. 
  JOHNSON 
  AND 
  LLEWELLYN 
  LLOYD. 
  

  

  they 
  can 
  subsist 
  is 
  always 
  present 
  in 
  these. 
  Impenetrable 
  forest 
  is 
  inhibitory 
  to 
  

   both 
  species. 
  G. 
  morsitans 
  is 
  dependent 
  on 
  a 
  certain 
  amount 
  of 
  shade 
  but 
  is 
  also 
  

   restricted 
  in 
  range 
  by 
  food 
  supply, 
  this 
  being 
  mainly 
  that 
  part 
  of 
  the 
  fauna 
  known 
  

   as 
  " 
  game." 
  

  

  3. 
  G. 
  palpalis 
  and 
  tachinoides 
  both 
  draw 
  a 
  considerable 
  proportion 
  of 
  their 
  food 
  

   from 
  non-mammalian 
  (probably 
  reptilian) 
  sources, 
  but 
  the 
  latter 
  is 
  less 
  addicted 
  to 
  

   this 
  diet, 
  preferring 
  mammalian 
  blood, 
  though 
  not 
  that 
  of 
  antelope 
  in 
  particular. 
  

   Both 
  can 
  thrive 
  where 
  the 
  wild 
  fauna 
  is 
  reduced 
  to 
  its 
  possible 
  minimum, 
  and 
  tachi- 
  

   noides 
  where 
  man 
  is 
  almost 
  the 
  only 
  host 
  available. 
  

  

  4. 
  The 
  breeding 
  haunts 
  of 
  G. 
  tachinoides 
  are 
  described, 
  Typically 
  they 
  are 
  in 
  

   patches 
  of 
  sand 
  in 
  open 
  places 
  in 
  the 
  forest 
  or 
  in 
  dry 
  stream-beds, 
  protected 
  from 
  

   the 
  sun's 
  rays 
  by 
  high 
  shade 
  but 
  usually 
  not 
  by 
  low 
  bushes 
  — 
  a 
  distinction 
  from 
  

   palpalis. 
  The 
  rate 
  of 
  breeding 
  is 
  restrained 
  in 
  the 
  wet 
  season 
  and 
  this 
  is 
  correlated 
  

   with 
  a 
  reduction 
  in 
  nutrition 
  due 
  to 
  seasonal 
  causes, 
  probably 
  high 
  undergrowth. 
  

   There 
  is 
  no 
  striking 
  disproportion 
  in 
  the 
  sexes 
  in 
  collections 
  of 
  tachinoides 
  caught 
  

   by 
  the 
  net. 
  

  

  5. 
  The 
  trypanosome 
  infections 
  of 
  the 
  flies 
  are 
  compared, 
  these 
  being 
  twice 
  as 
  

   numerous 
  in 
  morsitans 
  as 
  in 
  tachinoides, 
  and 
  twice 
  as 
  numerous 
  in 
  the 
  latter 
  as 
  they 
  

   are 
  in 
  palpalis. 
  In 
  tachinoides 
  the 
  trypanosomes 
  which 
  develop 
  in 
  the 
  proboscis, 
  

   or 
  invade 
  the 
  proboscis 
  when 
  the 
  infection 
  is 
  mature, 
  are 
  much 
  more 
  numerous 
  where 
  

   game 
  animals 
  are 
  present 
  than 
  when 
  these 
  are 
  virtually 
  absent. 
  These 
  are 
  the 
  main 
  

   stock-infecting 
  forms. 
  

  

  A 
  member 
  of 
  each 
  of 
  the 
  three 
  groups 
  of 
  pathogenic 
  trypanosomes 
  has 
  been 
  

   recovered 
  from 
  tachinoides. 
  

  

  Data 
  are 
  insufficient 
  to 
  estimate 
  the 
  local 
  importance 
  of 
  palpalis 
  as 
  a 
  disease 
  

   carrier 
  of 
  domestic 
  stock, 
  but 
  compared 
  with 
  tachinoides 
  it 
  is 
  of 
  small 
  importance, 
  

   since 
  its 
  range 
  is 
  greatly 
  restricted 
  in 
  the 
  main 
  cattle 
  country, 
  whereas 
  tachinoides 
  

   ranges 
  widely 
  in 
  contact 
  with 
  cattle 
  and 
  is 
  not 
  avoided. 
  

  

  G. 
  morsitans 
  areas 
  are 
  definitely 
  avoided 
  by 
  stock 
  owners 
  seeking 
  grazing 
  grounds 
  

   and 
  so 
  the 
  fly 
  has 
  not 
  great 
  opportunity 
  of 
  infecting 
  domestic 
  stock. 
  Its 
  importance 
  

   lies 
  in 
  the 
  fact 
  that 
  it 
  prohibits 
  expansion 
  and 
  renders 
  the 
  best 
  grazing 
  country 
  

   untenable, 
  but 
  there 
  is 
  no 
  reason 
  to 
  suppose 
  that 
  it 
  is 
  spreading. 
  

  

  6. 
  G. 
  tachinoides 
  is 
  shown 
  to 
  be 
  the 
  carrier 
  of 
  sleeping 
  sickness 
  in 
  the 
  north-eastern 
  

   and 
  eastern 
  parts 
  of 
  the 
  country. 
  Epidemics 
  of 
  the 
  disease 
  are 
  liable 
  to 
  occur 
  when 
  

   new 
  farms 
  are 
  made 
  in 
  contact 
  with 
  its 
  haunts. 
  This 
  curtails 
  expansion 
  of 
  population 
  

   and 
  the 
  farming 
  of 
  the 
  land, 
  which 
  is 
  the 
  best 
  remedy 
  against 
  tsetse-flies. 
  

  

  7. 
  It 
  is 
  therefore 
  clear 
  that 
  G. 
  tachinoides 
  is 
  the 
  most 
  important 
  tsetse-fly 
  in 
  the 
  

   Northern 
  Provinces, 
  and 
  we 
  propose 
  to 
  concentrate 
  our 
  work 
  on 
  an 
  attempt 
  to 
  dis- 
  

   cover 
  means 
  for 
  its 
  control. 
  This 
  will 
  be 
  carried 
  out 
  in 
  the 
  densely 
  populated 
  parts 
  

   of 
  South 
  Kano 
  Province, 
  where 
  the 
  prospects 
  of 
  prophylaxis 
  appear 
  to 
  be 
  most 
  

   promising. 
  It 
  is 
  anticipated 
  that 
  the 
  work 
  will 
  resolve 
  itself 
  into 
  a 
  study 
  of 
  clearing 
  

   problems, 
  since 
  we 
  have 
  already 
  shown 
  that 
  the 
  fly 
  may 
  not 
  be 
  controlled, 
  or 
  even 
  

   completely 
  sterilised, 
  by 
  any 
  practicable 
  curtailment 
  of 
  its 
  food 
  supply. 
  

  

  REFERENCES. 
  

  

  1. 
  Dr. 
  J. 
  W. 
  Scott 
  Macfie. 
  Distribution 
  of 
  Glossina 
  in 
  the 
  Ilorin 
  Province 
  of 
  

   Northern 
  Nigeria. 
  Bulletin 
  of 
  Entomological 
  Research, 
  iv, 
  pt. 
  1. 
  

  

  2. 
  Dr. 
  J. 
  J. 
  Simpson. 
  Entomological 
  Research 
  in 
  British 
  West 
  Africa 
  — 
  Northern 
  

   Nigeria. 
  Bulletin 
  of 
  Entomological 
  Research, 
  ii, 
  pt. 
  4. 
  

  

  3. 
  W. 
  F. 
  Fiske. 
  Investigation 
  into 
  the 
  Bionomics 
  of 
  G. 
  palpalis. 
  Bulletin 
  of 
  

   Entomological 
  Research, 
  x, 
  pt. 
  4. 
  

  

  4. 
  Reports 
  of 
  the 
  Sleeping 
  Sickness 
  Commission 
  of 
  the 
  Royal 
  Societv, 
  Nos. 
  XV 
  

   and 
  XVI. 
  

  

  