﻿390 
  

  

  W. 
  B. 
  JOHNSON 
  AND 
  LLEWELLYN 
  LLOYD. 
  

  

  are 
  relatively 
  light, 
  but 
  the 
  infections 
  indicating 
  the 
  pecorum 
  and 
  vivax 
  groups 
  are 
  

   respectively 
  nearly 
  three 
  and 
  four 
  times 
  as 
  great 
  as 
  in 
  the 
  minimum 
  game 
  areas. 
  

   G. 
  morsitans 
  compared 
  with 
  tachinoides 
  in 
  the 
  game 
  areas 
  shows 
  more 
  infections 
  

   of 
  gut 
  only, 
  four 
  times 
  as 
  many 
  infections 
  indicating 
  the 
  pecorum 
  group, 
  and 
  twice 
  

   as 
  many 
  indicating 
  the 
  vivax 
  group. 
  Evidence 
  was 
  given 
  above 
  (see 
  Table 
  II 
  and 
  

   p. 
  384) 
  that 
  tachinoides 
  obtains 
  a 
  smaller 
  proportion 
  of 
  its 
  food 
  from 
  the 
  game 
  animals 
  

   than 
  does 
  morsitans, 
  and 
  this 
  is 
  further 
  evidence, 
  since 
  it 
  must 
  be 
  admitted 
  that 
  

   the 
  main 
  source 
  of 
  the 
  tsetse-borne 
  pathogenic 
  trypanosomes 
  of 
  domestic 
  stock 
  is 
  

   to 
  be 
  found 
  in 
  the 
  wild 
  game. 
  

  

  TABLE 
  V. 
  

  

  Contrasting 
  the 
  Prevalence 
  of 
  Flagellates 
  in 
  G. 
  tachinoides 
  and 
  G. 
  morsitans 
  in 
  areas 
  where 
  Large 
  

  

  Game 
  is 
  absent 
  or 
  present. 
  

  

  (A). 
  In 
  absence 
  of 
  large 
  game. 
  

  

  Species. 
  

  

  Number 
  

   examined. 
  

  

  Percentage 
  showing 
  flagellates 
  in 
  : 
  — 
  

  

  Total 
  

  

  percentage 
  

  

  infected. 
  

  

  Gut 
  

  

  only. 
  

  

  Gut 
  and 
  

   proboscis. 
  

  

  Proboscis 
  

   only. 
  

  

  G. 
  tachinoides 
  

   G. 
  morsitans 
  

  

  407 
  

  

  Not 
  

   encountered 
  

  

  9-3 
  

  

  0-5 
  

  

  1-7 
  

  

  11-5 
  

  

  (B). 
  In 
  presence 
  of 
  large 
  game. 
  

  

  Species. 
  

  

  Number 
  

   examined. 
  

  

  Percentage 
  

  

  showing 
  flagellates 
  in 
  : 
  — 
  

  

  Total 
  

  

  percentage 
  

  

  infected. 
  

  

  Gut 
  

  

  only. 
  

  

  Gut 
  and 
  

   proboscis. 
  

  

  Proboscis 
  

   only. 
  

  

  G. 
  tachinoides 
  

   G. 
  morsitans 
  

  

  1,093 
  

   500 
  

  

  3-1 
  

   5-2 
  

  

  1-3 
  

   6-0 
  

  

  6-8 
  

   15-2 
  

  

  11-2 
  

  

  26-4 
  

  

  VII. 
  — 
  Relation 
  of 
  Tsetse-flies 
  to 
  Domestic 
  Stock. 
  

  

  The 
  value 
  of 
  the 
  domestic 
  stock 
  of 
  the 
  Northern 
  Provinces 
  of 
  Nigeria 
  is 
  very 
  

   considerable. 
  The 
  estimated 
  numbers 
  of 
  the 
  various 
  animals 
  in 
  1920 
  were 
  as 
  

   follows 
  : 
  horses, 
  132,000 
  ; 
  cattle, 
  2,400,000 
  ; 
  sheep, 
  2,060,000 
  ; 
  goats, 
  3,820,000 
  ; 
  

   donkeys, 
  352,000 
  ; 
  camels, 
  4,146 
  ; 
  swine, 
  44,000. 
  The 
  presence 
  of 
  tsetse-flies 
  

   among 
  these 
  is 
  an 
  important 
  matter, 
  as, 
  apart 
  from 
  the 
  numerous 
  deaths 
  due 
  to 
  

   trypanosomiasis, 
  much 
  of 
  the 
  best 
  grazing 
  country 
  is 
  closed 
  to 
  the 
  stock-owners 
  

   on 
  account 
  of 
  tsetse. 
  In 
  many 
  places 
  they 
  are 
  confined 
  to 
  dry 
  areas 
  where 
  the 
  

   grazing 
  is 
  poor 
  for 
  a 
  large 
  part 
  of 
  the 
  year 
  and 
  where 
  they 
  are 
  watered 
  from 
  deep 
  

   wells, 
  when 
  only 
  a 
  few 
  miles 
  away 
  is 
  an 
  area 
  of 
  excellent 
  grazing 
  with 
  permanent 
  

   surface 
  water 
  which 
  it 
  is 
  fatal 
  to 
  enter. 
  At 
  Gadam, 
  for 
  instance, 
  in 
  Gombe 
  Division, 
  

   cattle 
  were 
  so 
  numerous 
  as 
  to 
  have 
  beaten 
  down 
  the 
  whole 
  of 
  the 
  dry 
  grass 
  within 
  

   a 
  mile 
  or 
  two 
  of 
  the 
  town, 
  and 
  gathered 
  in 
  immense 
  numbers 
  at 
  the 
  scanty 
  wells, 
  

  

  