﻿392 
  W. 
  F. 
  FISKE. 
  

  

  It 
  is 
  important 
  to 
  know 
  into 
  which 
  category 
  any 
  given 
  host 
  species 
  falls, 
  if 
  squarely 
  

   in 
  either. 
  It 
  is 
  certain 
  that 
  a 
  repulsive 
  host 
  will 
  not 
  attract 
  a 
  " 
  following 
  swarm," 
  

   and 
  notes 
  on 
  observations 
  of 
  such 
  swarms 
  in 
  association 
  with 
  any 
  particular 
  host 
  

   are 
  r 
  valuable 
  in 
  doubtful 
  cases. 
  

  

  There 
  are 
  two 
  host 
  species, 
  crocodile 
  and 
  Varanus, 
  which 
  form, 
  apparently 
  by 
  them- 
  

   selves, 
  a 
  category 
  of 
  most 
  favoured 
  hosts. 
  They 
  are 
  not 
  only 
  most 
  attractive 
  to 
  fly, 
  but 
  

   the 
  most 
  favoured 
  and 
  best 
  protected 
  breeding 
  grounds 
  of 
  the 
  fly 
  are 
  frequently 
  identical 
  

   with 
  either 
  (a) 
  spots 
  selected 
  by 
  crocodiles 
  as 
  its 
  own 
  breeding 
  grounds, 
  or 
  (b) 
  spots 
  

   selected 
  by 
  Varanus 
  as 
  a 
  basking 
  ground. 
  (The 
  female 
  crocodiles 
  habitually 
  frequent 
  

   their 
  breeding 
  grounds, 
  and 
  bask 
  over 
  the 
  spot 
  where 
  their 
  eggs 
  are 
  buried.) 
  

  

  On 
  this 
  account 
  Glossina 
  palpalis 
  becomes 
  something 
  like 
  a 
  specific 
  parasite 
  of 
  

   these 
  reptiles, 
  suggesting 
  not 
  distantly 
  those 
  domiciliary 
  parasites 
  that 
  do 
  not 
  live 
  

   on 
  the 
  body 
  but 
  in 
  the 
  nests 
  or 
  domiciles 
  of 
  their 
  hosts, 
  and 
  which 
  are 
  specifically 
  

   adapted 
  to 
  such 
  a 
  mode 
  of 
  life. 
  

  

  VI 
  (6). 
  The 
  Habits 
  and 
  Habitats 
  of 
  the 
  Hosts 
  of 
  Glossina 
  palpalis 
  in 
  the 
  

   Region 
  of 
  Victoria 
  Nyanza. 
  

  

  The 
  following 
  very 
  general 
  notes 
  and 
  observations 
  are 
  drawn 
  up 
  with 
  the 
  idea 
  of 
  

   indicating 
  the 
  practicability 
  of 
  controlling 
  the 
  fly 
  through 
  extermination 
  of 
  its 
  hosts. 
  

   No 
  proposition 
  of 
  this 
  character 
  should 
  be 
  considered, 
  however, 
  without 
  also 
  

   considering 
  the 
  data 
  presented 
  in 
  Sect. 
  II 
  (d). 
  

  

  Crocodile. 
  

  

  Crocodile 
  is 
  undoubtedly 
  the 
  most 
  important 
  host 
  of 
  Glossina 
  palpalis 
  in 
  this- 
  

   region. 
  It 
  is 
  common 
  nearly 
  everywhere, 
  on 
  islands 
  and 
  mainland 
  alike, 
  and 
  on 
  

   or 
  off 
  rocky, 
  marshy, 
  clay-banked, 
  sandy 
  and 
  gravelly 
  shores. 
  It 
  is 
  excessively 
  

   numerous 
  at 
  times 
  along 
  certain 
  reaches 
  of 
  marshy 
  or 
  papyrus-fringed 
  shore 
  (notably 
  

   on 
  certain 
  floating 
  islets 
  north 
  of 
  the 
  island 
  of 
  Bunjako 
  where 
  in 
  August 
  1915 
  dozens- 
  

   and 
  scores 
  were 
  seen 
  basking 
  together), 
  but 
  it 
  cannot 
  breed 
  in 
  such 
  places. 
  These 
  

   are 
  its 
  feeding 
  grounds, 
  and 
  individuals 
  frequenting 
  them 
  must 
  go, 
  in 
  some 
  cases 
  

   considerable 
  distances, 
  in 
  search 
  of 
  the 
  sandy 
  or 
  gravelly 
  places 
  in 
  which 
  alone 
  they 
  

   deposit 
  their 
  eggs. 
  Much 
  frequented 
  breeding 
  grounds 
  were 
  found 
  — 
  notably 
  on 
  the 
  

   mainland 
  in 
  that 
  district 
  of 
  Buddu 
  known 
  as 
  the 
  Swamba, 
  and 
  on 
  certain 
  islets, 
  

   notably 
  that 
  known 
  as 
  Dwavannu, 
  which 
  lies 
  just 
  off 
  the 
  southern 
  tip 
  of 
  Luambu 
  

   Island, 
  where 
  nearly 
  a 
  score 
  of 
  occupied 
  " 
  nests 
  " 
  were 
  found 
  in 
  July 
  1915. 
  

  

  The 
  females 
  brood 
  daily 
  for 
  long 
  periods 
  over 
  the 
  precise 
  spot 
  where 
  their 
  eggs 
  

   lie 
  buried, 
  and 
  at 
  such 
  times 
  are 
  especially 
  exposed 
  to 
  attack 
  by 
  Glossina, 
  and 
  

   provide 
  for 
  it 
  a 
  regular 
  supply 
  of 
  food. 
  

  

  Neither 
  breeding 
  nor 
  basking 
  spots 
  are 
  very 
  far 
  from 
  the 
  shore 
  ; 
  perhaps 
  never 
  

   more 
  than 
  100 
  and 
  rarely 
  more 
  than 
  50 
  yards. 
  In 
  consequence 
  inland 
  range 
  of 
  the 
  

   fly 
  is 
  not 
  affected 
  by 
  this 
  host, 
  as 
  it 
  may 
  be 
  by 
  Varanus. 
  

  

  If 
  it 
  were 
  deemed 
  desirable 
  to 
  reduce 
  the 
  numbers 
  of 
  these 
  reptiles, 
  it 
  could 
  probably 
  

   be 
  done 
  by 
  placing 
  a 
  small 
  bounty 
  on 
  their 
  eggs 
  or 
  by 
  locating 
  all 
  the 
  favoured 
  breeding 
  

   places 
  and 
  making 
  regular 
  rounds 
  of 
  egg 
  destruction. 
  In 
  GermanEast 
  Africa, 
  I 
  was 
  in- 
  

   formed, 
  abounty 
  hadbeenplaced 
  on 
  eggs 
  as 
  a 
  measure 
  for 
  reducing 
  the 
  density 
  of 
  Glossina. 
  

   But 
  such 
  measures, 
  to 
  be 
  really 
  effective, 
  ought 
  to 
  include 
  the 
  lake 
  as 
  a 
  whole, 
  for 
  the 
  

   animals 
  undoubtedly 
  move 
  about 
  considerably 
  in 
  search 
  of 
  feeding 
  and 
  breeding 
  grounds. 
  

  

  