﻿378 
  W. 
  F. 
  FISKE. 
  

  

  On 
  Situtunga. 
  Bugalla 
  Island, 
  December 
  1914. 
  

  

  (Original 
  note 
  lost.) 
  On 
  entering 
  an 
  open 
  space 
  in 
  the 
  jungle 
  where 
  formerly 
  

   were 
  plantations, 
  a 
  small 
  herd 
  of 
  two 
  female 
  and 
  two 
  half-grown 
  male 
  situtunga 
  was 
  

   seen, 
  with 
  other 
  animals 
  feeding 
  in 
  the 
  edge 
  of 
  the 
  jungle 
  out 
  of 
  sight. 
  Those 
  in 
  

   sight 
  did 
  not 
  immediately 
  see 
  me, 
  who 
  stood 
  motionless 
  watching 
  them, 
  nor 
  upon 
  

   seeing 
  me 
  did 
  they 
  betray 
  alarm 
  or 
  more 
  than 
  mild 
  curiosity. 
  The 
  whole 
  herd 
  

   moved 
  in 
  my 
  direction 
  and 
  one 
  female 
  approached 
  within 
  three 
  yards. 
  Each 
  animal 
  

   was 
  followed 
  by 
  a 
  small 
  swarm 
  of 
  tsetse 
  — 
  perhaps 
  15 
  or 
  20 
  flies 
  — 
  few 
  of 
  them 
  on 
  the 
  

   animal 
  itself, 
  but 
  principally 
  on 
  the 
  vegetation 
  close 
  at 
  hand, 
  or 
  hovering 
  about. 
  

   Not 
  one 
  of 
  the 
  flies 
  was 
  seen 
  to 
  feed, 
  nor 
  did 
  the 
  animals 
  show 
  annoyance 
  at 
  their 
  

   presence. 
  On 
  becoming 
  alarmed 
  the 
  antelopes 
  made 
  off 
  without 
  undue 
  haste, 
  

   the 
  flies 
  following. 
  

  

  The 
  above 
  may 
  serve 
  in 
  some 
  manner 
  to 
  make 
  clear 
  the 
  difference 
  between 
  the 
  

   behaviour 
  of 
  fly 
  toward 
  a 
  favoured 
  and 
  complacent 
  host, 
  and 
  such 
  another 
  as 
  man, 
  

   who 
  is 
  neither 
  favoured 
  nor 
  complacent. 
  Anyone 
  passing 
  through 
  infested 
  territory 
  

   and 
  aware 
  of 
  two 
  or 
  three, 
  or 
  perhaps 
  half 
  a 
  dozen, 
  tsetse 
  constantly 
  hovering 
  about 
  

   him 
  is 
  certain 
  to 
  receive 
  the 
  impression 
  that 
  this 
  number 
  of 
  flies 
  is 
  persistently 
  

   following 
  him. 
  In 
  the 
  case 
  of 
  Glossina 
  morsitans 
  the 
  impression 
  would, 
  probably, 
  

   be 
  correct, 
  for 
  man 
  will 
  collect 
  a 
  following 
  swarm 
  of 
  this 
  species 
  ; 
  but 
  with 
  Glossina 
  

   falfalis 
  it 
  is 
  incorrect. 
  The 
  same 
  individual 
  flies 
  will 
  not 
  follow 
  a 
  man 
  for 
  more 
  

   than 
  a 
  few 
  minutes 
  unless 
  they 
  are 
  very 
  hungry, 
  but 
  will 
  quickly 
  drop 
  behind 
  and 
  

   be 
  replaced, 
  perhaps 
  by 
  others. 
  This 
  is 
  easily 
  proved 
  by 
  catching 
  them 
  just 
  as 
  

   they 
  appear 
  ; 
  one 
  will 
  quickly 
  catch 
  many 
  times 
  more 
  than 
  appear 
  to 
  be 
  following 
  

   at 
  any 
  one 
  time. 
  

  

  The 
  explanation 
  of 
  the 
  "following 
  swarm" 
  with 
  Glossina 
  palpalis 
  is, 
  without 
  

   doubt, 
  identical 
  with 
  that 
  put 
  forward 
  by 
  Lloyd 
  for 
  the 
  " 
  following 
  swarm 
  ' 
  of 
  

   Glossina 
  morsitans. 
  It 
  is 
  the 
  assembling 
  habit 
  of 
  the 
  males 
  ; 
  first, 
  to 
  linger 
  along 
  

   the 
  routes 
  followed 
  by 
  the 
  food-hunting 
  females 
  ; 
  secondly, 
  to 
  examine 
  any 
  strange 
  

   object 
  coming 
  in 
  range 
  of 
  vision 
  ; 
  and 
  finally, 
  on 
  encountering 
  a 
  complacent 
  host 
  

   of 
  a 
  favoured 
  species, 
  to 
  remain 
  by 
  it 
  ; 
  for 
  in 
  these 
  ways 
  they 
  are 
  most 
  likely 
  to 
  come 
  

   into 
  contact 
  with 
  the 
  seclusive 
  females. 
  

  

  Nothing 
  else 
  in 
  the 
  habits 
  of 
  the 
  fly 
  affords 
  more 
  convincing 
  evidence 
  of 
  their 
  

   unwillim 
  ness 
  to 
  feed 
  upon 
  man, 
  unless 
  they 
  are 
  forced 
  by 
  hunger. 
  Far 
  from 
  attracting 
  

   a 
  following 
  swarm, 
  man 
  cannot 
  even 
  hold 
  one 
  that 
  has 
  already 
  been 
  attracted 
  to 
  some 
  

   other 
  host 
  ; 
  if 
  by 
  his 
  approach 
  he 
  startles 
  the 
  favoured 
  host 
  into 
  flight, 
  there 
  is 
  not 
  

   the 
  slightest 
  tendency 
  on 
  the 
  part 
  of 
  the 
  following 
  flies 
  to 
  turn 
  their 
  attention 
  to 
  him, 
  

   but 
  invariably, 
  as 
  in 
  the 
  cases 
  noted 
  above, 
  the 
  swarm 
  has 
  dispersed 
  without 
  the 
  

   flies 
  paying 
  as 
  much 
  attention 
  to 
  the 
  intruder 
  as 
  is 
  usual 
  when 
  other 
  hosts 
  are 
  about.. 
  

  

  IV 
  (b). 
  Conditions 
  under 
  which 
  a 
  Following 
  Swarm 
  will 
  Collect. 
  

  

  More 
  than 
  25 
  separate 
  experiments 
  were 
  made 
  with 
  various 
  wild 
  and 
  dumestic 
  

   animals 
  tethered 
  at 
  points 
  where 
  they 
  were 
  exposed 
  to 
  columns 
  of 
  food- 
  minting 
  

   flies, 
  mainly 
  to 
  ascertain 
  the 
  host 
  preferences 
  and 
  feeding 
  habits 
  of 
  the 
  insect, 
  and 
  

   finally 
  in 
  a 
  specific 
  effort 
  to 
  induce 
  a 
  " 
  following 
  swarm 
  " 
  to 
  collect 
  under 
  observation. 
  

   In 
  the 
  very 
  first 
  experiment 
  in 
  the 
  series 
  such 
  a 
  swarm 
  did 
  collect 
  upon 
  a 
  tethered 
  

   Varanus, 
  but 
  all 
  other 
  experiments 
  failed 
  in 
  this 
  respect. 
  

  

  