﻿388 
  W. 
  F. 
  FISKE. 
  

  

  shelter 
  is 
  repulsive 
  and 
  no 
  indication 
  of 
  any 
  sort 
  of 
  food 
  was 
  seen. 
  To 
  the 
  south 
  

   there 
  are 
  situtunga 
  and 
  perhaps 
  other 
  host 
  animals, 
  but 
  shelter 
  is 
  repulsive 
  and 
  

   no 
  breeding 
  grounds 
  were 
  seen. 
  Conditions 
  of 
  life 
  at 
  the 
  very 
  mouth 
  of 
  the 
  creek, 
  

   over 
  a 
  radius 
  of 
  hardly 
  more 
  than 
  50 
  yards, 
  are 
  highly 
  favourable 
  for 
  tsetse, 
  

   but 
  favourable 
  conditions 
  are 
  extremely 
  localised, 
  making 
  for 
  a 
  sharply 
  defined 
  

   colony 
  that 
  fuses 
  with 
  a 
  small 
  colony 
  at 
  Kalkosa 
  landing 
  (point 
  40 
  in 
  Fig. 
  5), 
  

   to 
  the 
  southward, 
  but 
  tapers 
  away 
  to 
  a 
  minimum 
  of 
  *5 
  at 
  Bale 
  (about 
  1,200 
  yards 
  

   beyond 
  point 
  53), 
  where 
  a 
  colony 
  yet 
  further 
  north 
  fuses 
  narrowly 
  with 
  it. 
  

  

  Mujuzi 
  Creek 
  is 
  almost 
  a 
  river, 
  being 
  at 
  points 
  some 
  10 
  yards 
  in 
  width 
  and 
  of 
  

   considerable 
  depth. 
  Its 
  shores 
  are 
  thickly 
  wooded, 
  and 
  cannot 
  well 
  be 
  followed 
  

   because 
  of 
  the 
  tangled 
  vegetation. 
  There 
  are 
  occasional 
  pools 
  with 
  low 
  sand 
  bars, 
  

   as 
  at 
  points 
  45C 
  and 
  45D. 
  The 
  stream 
  was 
  quite 
  open 
  as 
  far 
  as 
  point 
  45E, 
  where 
  

   it 
  was 
  choked 
  with 
  floating 
  vegetation 
  which 
  extended 
  for 
  a 
  considerable 
  distance. 
  

   At 
  points 
  beyond 
  45F 
  it 
  was 
  open 
  again, 
  and 
  at 
  one 
  point 
  ran 
  through 
  a 
  tract 
  of 
  

   woodland 
  which 
  seemed 
  the 
  headquarters 
  of 
  a 
  herd 
  of 
  buffalo, 
  but 
  beyond 
  point 
  

   45F, 
  which 
  was 
  approximately 
  2 
  miles 
  from 
  its 
  mouth, 
  no 
  fly 
  was 
  seen. 
  At 
  no 
  

   point 
  from 
  the 
  mouth 
  inland 
  was 
  shelter 
  especially 
  attractive 
  ; 
  no 
  breeding 
  grounds 
  

   were 
  seen, 
  and 
  host 
  animals 
  were 
  certainly 
  not 
  abundant. 
  

  

  If 
  allowance 
  is 
  made 
  for 
  the 
  general 
  attractiveness 
  of 
  the 
  shelter 
  from 
  point 
  45 
  

   to 
  beyond 
  point 
  46 
  along 
  the 
  lake 
  shore, 
  the 
  falling 
  off 
  in 
  density 
  of 
  fly 
  appears 
  

   to 
  be 
  approximately 
  the 
  same 
  on 
  the 
  lake 
  shore 
  northward 
  to 
  Bale, 
  and 
  along 
  the 
  

   creek 
  inland. 
  It 
  is 
  more 
  pronounced 
  along 
  the 
  creek, 
  but 
  not 
  very 
  much 
  more. 
  

   The 
  conditions 
  of 
  life 
  are 
  unfavourable 
  to 
  tsetse 
  in 
  all 
  three 
  directions 
  from 
  the 
  

   colony 
  centre, 
  and 
  infestations 
  of 
  the 
  creek 
  banks 
  and 
  lake 
  shore 
  alike 
  for 
  a 
  distance 
  

   of 
  from 
  two 
  to 
  three 
  miles 
  is 
  plainly 
  due 
  to 
  the 
  existence 
  of 
  exceptionally 
  favourable 
  

   conditions 
  in 
  the 
  extremely 
  limited 
  space 
  around 
  the 
  mouth 
  of 
  the 
  creek. 
  

  

  Extension 
  of 
  range 
  inland 
  along 
  other 
  creeks 
  wide 
  enough 
  to 
  create 
  something 
  

   of 
  an 
  alley- 
  way 
  through 
  the 
  bush 
  or 
  forest 
  for 
  the 
  moving 
  flies 
  to 
  follow 
  has 
  been 
  

   found 
  to 
  be 
  much 
  as 
  in 
  this 
  instance.* 
  The 
  flies 
  follow 
  the 
  waterways 
  much 
  as 
  they 
  

   follow 
  the 
  lake 
  shore. 
  But 
  as 
  yet 
  no 
  colony 
  centre, 
  or 
  semblance 
  of 
  such 
  comparable 
  

   to 
  the 
  hill 
  colony 
  on 
  Mbugwe 
  Island 
  (Sect. 
  V 
  (d) 
  ) 
  or 
  the 
  inland 
  colony 
  in 
  Bujaju 
  

   (Sect. 
  V 
  (e) 
  ) 
  has 
  been 
  discovered 
  on 
  the 
  banks 
  of 
  any 
  stream. 
  

  

  Every 
  bit 
  of 
  evidence 
  that 
  has 
  been 
  gathered 
  supports 
  this 
  final 
  conclusion 
  con- 
  

   cerning 
  the 
  range 
  of 
  fly 
  inland 
  from 
  the 
  lake 
  shore 
  ; 
  it 
  is 
  primarily 
  controlled 
  by 
  

   the 
  distribution 
  of 
  host 
  animals, 
  and 
  there 
  is 
  nothing 
  to 
  indicate 
  that 
  this 
  tsetse 
  

   requires 
  open 
  water 
  or 
  humid 
  conditions, 
  or 
  that 
  water 
  is 
  even 
  attractive 
  to 
  it. 
  

   Its 
  favoured 
  hosts 
  are 
  amphibious 
  in 
  habit 
  ; 
  the 
  most 
  attractive 
  types 
  of 
  shelter 
  

   occur 
  more 
  commonly 
  near 
  the 
  shore 
  than 
  inland 
  ; 
  and 
  it 
  rarely 
  finds 
  good 
  breeding 
  

   places 
  elsewhere. 
  

  

  It 
  may 
  be 
  added 
  that 
  every 
  instance 
  in 
  which 
  fly 
  was 
  encountered 
  other 
  than 
  

   as 
  mere 
  stragglers 
  at 
  a 
  distance 
  greater 
  than 
  500 
  yards 
  from 
  the 
  lake 
  shore 
  has 
  

   been 
  covered 
  in 
  this 
  section. 
  

  

  * 
  If 
  the 
  stream 
  is 
  so 
  small 
  that 
  no 
  break 
  is 
  caused 
  in 
  the 
  continuity 
  of 
  the 
  forest, 
  fly 
  

   has 
  not 
  been 
  observed 
  to 
  follow 
  it. 
  

  

  