﻿ENTOMOLOGICAL 
  ASPECTS 
  OF 
  AN 
  OUTBREAK 
  OF 
  SLEEPING 
  SICKNESS. 
  361 
  

  

  are 
  concerned, 
  is 
  not 
  the 
  direct 
  protection 
  of 
  the 
  existing 
  herds 
  (except 
  in 
  the 
  matter 
  

   of 
  providing 
  fly-free 
  cattle 
  routes), 
  but 
  (1) 
  the 
  effective 
  invasion 
  of 
  the 
  adjoining 
  

   tsetse 
  areas 
  pari 
  passu 
  with 
  the 
  increase 
  of 
  the 
  cattle 
  so 
  as 
  to 
  obviate 
  the 
  great 
  losses 
  

   that 
  now 
  apparently 
  occur 
  through 
  overstocking 
  ; 
  (2) 
  the 
  prevention 
  of 
  the 
  invasions 
  

   by 
  bush, 
  entailing 
  invasion 
  by 
  tsetse, 
  that 
  take 
  place 
  as 
  the 
  result 
  of 
  losses 
  anywhere 
  

   or 
  of 
  temporary 
  removals 
  of 
  cattle 
  from 
  the 
  margins 
  of 
  clear 
  country. 
  The 
  former 
  

   point 
  is 
  of 
  great 
  practical 
  importance. 
  In 
  the 
  Tabora 
  district 
  alone, 
  according 
  to 
  

   Stiebel, 
  there 
  are 
  " 
  40,000 
  square 
  miles 
  of 
  country, 
  and 
  of 
  this 
  probably 
  only 
  one 
  

   quarter, 
  at 
  the 
  outside 
  33 
  per 
  cent., 
  is 
  actually 
  free 
  from 
  fly, 
  and 
  that 
  carries 
  over 
  

   600,000 
  head 
  of 
  large 
  stock 
  in 
  addition 
  to 
  small 
  stock 
  and 
  a 
  population 
  of 
  a 
  quarter 
  

   of 
  a 
  million 
  agriculturists. 
  It 
  is 
  a 
  simple 
  sum 
  to 
  calculate 
  what 
  the 
  district 
  could 
  

   carry 
  if 
  we 
  could 
  eliminate 
  fly. 
  At 
  any 
  rate 
  it 
  should 
  carry 
  the 
  best 
  part 
  of 
  two 
  

   million 
  large 
  stock." 
  The 
  immediate 
  importance 
  of 
  this 
  wasted 
  grazing 
  lies 
  of 
  course 
  

   in 
  the 
  fact 
  that, 
  without 
  the 
  tsetse, 
  it 
  would 
  save 
  the 
  great 
  numbers 
  of 
  animals 
  that 
  

   are 
  stated 
  to 
  die 
  annually 
  from 
  overstocking. 
  

  

  I 
  have 
  referred 
  to 
  " 
  2 
  " 
  already. 
  At 
  Masanza 
  Mdogo, 
  just 
  north 
  of 
  Nasa, 
  the 
  

   bush 
  is 
  now 
  growing 
  up 
  in 
  parts 
  of 
  the 
  still 
  occupied 
  area, 
  the 
  fly 
  has 
  come 
  in 
  in 
  ones 
  

   and 
  twos, 
  beasts 
  are 
  being 
  lost, 
  and 
  the 
  people 
  discouraged, 
  as 
  the 
  ultimate 
  result 
  of 
  

   the 
  reduction 
  of 
  the 
  live-stock 
  below 
  its 
  bush-controlling 
  minimum 
  through 
  a 
  Masai 
  

   raid 
  that 
  took 
  place 
  before 
  the 
  war. 
  In 
  an 
  area 
  in 
  Ututwa 
  the 
  same 
  thing 
  has 
  

   happened 
  as 
  the 
  result 
  of 
  partial 
  human 
  depopulation 
  through 
  another 
  Masai 
  raid. 
  

   In 
  Chinyanga, 
  according 
  to 
  Stiebel, 
  fly 
  has 
  crept 
  into 
  country 
  where 
  there 
  is 
  scarcely 
  

   a 
  bush 
  more 
  than 
  six 
  feet 
  high 
  — 
  much 
  as 
  at 
  Masanza 
  Mdogo. 
  Mr. 
  E. 
  D. 
  Browne, 
  

   the 
  Senior 
  Commissioner 
  of 
  the 
  Arusha 
  District, 
  which 
  adjoins 
  the 
  Usukuma 
  area 
  on 
  

   the 
  east, 
  writes, 
  in 
  a 
  letter 
  dated 
  14th 
  September 
  1921, 
  " 
  There 
  is 
  no 
  possible 
  doubt 
  

   that 
  tsetse-fly 
  has 
  spread 
  into 
  inhabited 
  areas 
  since 
  March 
  1916, 
  when 
  I 
  first 
  came 
  to 
  

   Arusha. 
  In 
  the 
  case 
  of 
  the 
  Masai 
  it 
  has 
  caused 
  complete 
  abandonment 
  of 
  certain 
  

   areas, 
  and 
  in 
  the 
  case 
  of 
  agricultural 
  natives 
  an 
  abandonment 
  as 
  far 
  as 
  they 
  are 
  

   concerned 
  of 
  the 
  areas 
  formerly 
  used 
  for 
  grazing 
  purposes 
  ; 
  such 
  latter 
  abandonment 
  

   inevitably 
  leads 
  to 
  the 
  eventual 
  complete 
  abandonment 
  of 
  the 
  areas 
  encroached 
  

   upon, 
  because 
  no 
  native 
  will 
  willingly 
  for 
  protracted 
  periods 
  live 
  far 
  from 
  his 
  cattle, 
  

   nor 
  can 
  he 
  conveniently 
  do 
  so 
  for 
  family 
  reasons." 
  Mr. 
  Browne 
  refers, 
  of 
  course, 
  

   to 
  tribes 
  that 
  have 
  been 
  accustomed 
  to 
  keep 
  cattle, 
  and 
  the 
  fact, 
  stated 
  by 
  him 
  in 
  

   another 
  letter 
  (10.ix.21), 
  that 
  the 
  fly 
  areas 
  in 
  his 
  district 
  are 
  practically 
  uninhabited 
  

   bears 
  out 
  his 
  view. 
  To 
  return 
  to 
  the 
  Tabora 
  District, 
  " 
  Twenty 
  years 
  ago 
  Urambo 
  

   area 
  was 
  open 
  grass 
  country 
  carrying 
  huge 
  numbers 
  of 
  stock 
  ; 
  to-day 
  it 
  is 
  one 
  tsetse- 
  

   infested 
  bush." 
  

  

  One 
  or 
  two 
  other 
  instances 
  like 
  that 
  of 
  the 
  fly-free 
  bush 
  near 
  Musoma 
  may 
  still 
  

   exist 
  in 
  the 
  territory, 
  but, 
  in 
  general, 
  G. 
  morsitans 
  at 
  least 
  has 
  filled 
  up 
  the 
  areas 
  in 
  

   which 
  it 
  can 
  exist, 
  and 
  in 
  nearly 
  every 
  case 
  of 
  which 
  I 
  know 
  the 
  details 
  it 
  is 
  an 
  invasion 
  

   not 
  of 
  game 
  but 
  of 
  bush 
  that 
  spreads 
  it 
  farther. 
  The 
  position 
  appears 
  to 
  be 
  quite 
  

   serious, 
  and 
  the 
  remedy 
  for 
  this 
  insidious 
  invasion 
  is 
  not 
  game-destruction, 
  which 
  

   will 
  be 
  completely 
  without 
  effect, 
  but 
  (a) 
  such 
  measures 
  against 
  the 
  growth 
  of 
  the 
  

   bush 
  as 
  I 
  am 
  recommending 
  in 
  this 
  paper, 
  and 
  (b) 
  protection 
  of 
  the 
  cattle 
  against 
  

   cattle 
  diseases 
  generally 
  ; 
  for 
  it 
  cannot 
  be 
  emphasised 
  too 
  strongly 
  that 
  appreciable 
  

   losses 
  in 
  a 
  cattle 
  area 
  which 
  anywhere 
  adjoins 
  fly 
  means 
  invasion 
  somewhere 
  by 
  the 
  

   fly, 
  and 
  that 
  everything 
  which 
  fosters 
  the 
  cattle 
  industry 
  will 
  reinforce 
  our 
  own 
  

   invasion 
  of 
  fly 
  areas, 
  so 
  that 
  a 
  strong 
  Veterinary 
  Department 
  is, 
  indirectly, 
  an 
  

   important 
  measure 
  against 
  tsetse. 
  

  

  In 
  the 
  great, 
  clear, 
  populated 
  areas 
  of 
  the 
  Mwanza 
  and 
  North 
  Tabora 
  districts 
  

   it 
  is 
  the 
  cattle, 
  very 
  largely, 
  that 
  keep 
  the 
  country 
  clear. 
  Everywhere 
  are 
  stumps 
  

   that, 
  with 
  less 
  heavy 
  stocking, 
  grow 
  up 
  at 
  once 
  and 
  form 
  bush 
  that 
  harbours 
  tsetse. 
  

   On 
  the 
  other 
  hand, 
  cattle 
  can 
  do 
  nothing 
  against 
  trees 
  already 
  grown, 
  and 
  gradual 
  

   special 
  clearing 
  could 
  easily 
  be 
  undertaken 
  by 
  the 
  owners 
  who 
  abut 
  on 
  tsetse, 
  or 
  by 
  

  

  