﻿88 
  J. 
  O. 
  SHIRCORE 
  — 
  SUGGESTIONS 
  FOR 
  THE 
  LIMITATION 
  

  

  connecting 
  forest 
  as 
  soon 
  as 
  the 
  conditions 
  become 
  suitable. 
  This 
  is 
  actually 
  observed 
  

   to 
  take 
  place. 
  During 
  May, 
  June, 
  and 
  early 
  July, 
  tsetses 
  are 
  to 
  be 
  found 
  constantly, 
  

   though 
  in 
  small 
  numbers, 
  along 
  routes 
  where 
  during 
  August 
  and 
  September 
  they 
  

   absolutely 
  disappear, 
  or 
  are 
  present 
  in 
  almost 
  negligible 
  numbers, 
  or 
  only 
  at 
  odd 
  

   times. 
  This 
  applies 
  to 
  almost 
  all 
  the 
  main 
  routes, 
  except 
  just 
  at 
  and 
  opposite 
  the 
  

   four 
  centres 
  indicated. 
  During 
  late 
  September, 
  October 
  and 
  November 
  a 
  distinct 
  

   but 
  gradual 
  increase 
  becomes 
  evident, 
  and 
  during 
  November, 
  before 
  the 
  rains, 
  flies 
  

   re-appear 
  in 
  situations 
  in 
  which 
  they 
  were 
  to 
  be 
  found 
  early 
  in 
  May. 
  Radiations 
  

   from 
  the 
  primary 
  centres 
  begin 
  about 
  this 
  period, 
  so 
  far 
  as 
  the 
  physical 
  character 
  

   of 
  the 
  country, 
  the 
  large 
  garden 
  clearings 
  and 
  the 
  seasonal 
  conditions 
  allow. 
  With 
  

   the 
  onset 
  of 
  the 
  rains 
  the 
  spread 
  increases, 
  as 
  more 
  suitable 
  situations 
  are 
  created 
  ; 
  

   the 
  rough 
  stony 
  country 
  becomes 
  a 
  habitat 
  and 
  other 
  breeding 
  centres 
  — 
  " 
  secondary 
  

   centres 
  " 
  — 
  are 
  established. 
  The 
  fly 
  thus 
  continues 
  to 
  increase 
  until 
  the 
  rains 
  are 
  

   over, 
  the 
  streams 
  dry, 
  and 
  the 
  grass 
  withered, 
  and 
  then 
  the 
  hot 
  season 
  with 
  its 
  bush- 
  

   fires 
  once 
  more 
  performs 
  a 
  natural 
  prophylactic 
  measure. 
  

  

  On 
  regarding 
  the 
  subject 
  from 
  this 
  aspect, 
  the 
  measure 
  which 
  I 
  advocate 
  is 
  that 
  

   the 
  forest 
  connections 
  along 
  which 
  radiations 
  take 
  place 
  should 
  be 
  cut 
  off, 
  or 
  otherwise 
  

   dealt 
  with, 
  early 
  in 
  the 
  year, 
  about 
  May, 
  so 
  that 
  the 
  actual 
  " 
  primary 
  centres," 
  which 
  

   should 
  have 
  been 
  delimited 
  at 
  the 
  height 
  of 
  the 
  previous 
  dry 
  season, 
  are 
  isolated. 
  After 
  

   this 
  has 
  been 
  performed, 
  all 
  the 
  trees 
  in 
  these 
  centres 
  should 
  be 
  cut 
  down 
  and 
  left 
  to 
  

   dry, 
  and 
  by 
  the 
  end 
  of 
  July 
  or 
  August, 
  when 
  the 
  whole 
  country 
  is 
  parched 
  (grass-fires 
  

   having 
  been 
  strictly 
  prohibited 
  during 
  this 
  period), 
  wholesale 
  and 
  extensive 
  burning 
  

   should 
  be 
  carried 
  out 
  over 
  these 
  areas, 
  commencing 
  from 
  the 
  side 
  of 
  the 
  " 
  extensions 
  " 
  

   and 
  progressing 
  towards 
  the 
  main 
  and 
  isolated 
  bodies 
  of 
  fly. 
  At 
  Kuti, 
  Nyansato 
  

   and 
  Patsanjoka 
  (Rifu) 
  this 
  could 
  be 
  done, 
  and 
  with 
  especial 
  ease 
  at 
  the 
  last 
  situation. 
  

   At 
  Lingadsi 
  it 
  would 
  be 
  difficult, 
  but 
  sufficient 
  could 
  be 
  done 
  here 
  to 
  prevent 
  a 
  southern 
  

   extension 
  which 
  links 
  up 
  with 
  the 
  north 
  arm 
  of 
  the 
  Nyansato 
  area 
  during 
  the 
  rains. 
  

  

  If 
  " 
  extensions 
  " 
  depend 
  on 
  primary 
  sources, 
  as 
  they 
  undoubtedly 
  do, 
  then 
  it 
  must 
  

   needs 
  follow 
  that 
  their 
  limitation 
  or 
  the 
  lessening 
  of 
  their 
  numbers 
  must 
  lessen 
  the 
  

   formation 
  of 
  " 
  secondary 
  centres 
  " 
  and 
  their 
  " 
  extensions 
  " 
  and 
  will 
  therefore 
  curtail 
  

   the 
  distribution 
  and 
  numbers 
  of 
  the 
  fly. 
  

  

  Game 
  plays 
  a 
  minor 
  part 
  in 
  the 
  actual 
  habitat 
  of 
  G. 
  morsitans. 
  It 
  is 
  true 
  that 
  in 
  

   the 
  above-mentioned 
  areas 
  game 
  is 
  plentiful 
  and 
  that 
  blood 
  is 
  necessary 
  to 
  the 
  life 
  of 
  

   the 
  fly, 
  but 
  there 
  are 
  numerous 
  situations 
  where 
  game 
  is 
  present 
  in 
  this 
  same 
  pro- 
  

   hibited 
  area, 
  yet 
  fly 
  are 
  not 
  found, 
  and 
  where 
  fly 
  though 
  present 
  during 
  the 
  wet-sesaon 
  

   are 
  absent 
  during 
  the 
  dry. 
  

  

  The 
  effect 
  of 
  prophylactic 
  forest 
  cleaning 
  on 
  G. 
  morsitans. 
  

  

  With 
  a 
  view 
  to 
  indicate 
  the 
  results 
  of 
  even 
  moderate 
  clearings 
  of 
  some 
  150 
  yards 
  

   around 
  villages 
  in 
  the 
  " 
  proclaimed 
  area," 
  a 
  few 
  observations 
  may 
  well 
  be 
  recorded. 
  

   Before 
  such 
  measures 
  were 
  adopted 
  it 
  was 
  noticed 
  that 
  clearings 
  made 
  for 
  agricultural 
  

   purposes 
  by 
  the 
  inhabitants 
  of 
  a 
  certain 
  chain 
  of 
  villages 
  lying 
  east 
  of 
  Mtalamanja, 
  

   and 
  north 
  and 
  south 
  of 
  the 
  River 
  Lipimbi 
  along 
  its 
  course 
  to 
  Lake 
  Nyasa, 
  shewed 
  a 
  

   decided 
  effect, 
  as 
  compared 
  with 
  other 
  parts 
  of 
  the 
  district, 
  on 
  the 
  distribution 
  of 
  

   G. 
  morsitans, 
  which 
  was 
  further 
  emphasised 
  by 
  the 
  clearing 
  of 
  areas 
  in 
  the 
  vicinity 
  of 
  

  

  