﻿46 
  Dr. 
  H. 
  Eltringham 
  on 
  Butterfly 
  Vision. 
  

  

  one 
  of 
  the 
  most 
  convincing 
  incidents 
  of 
  the 
  afternoon's 
  

   work. 
  I 
  had 
  the 
  advantage 
  on 
  that 
  occasion 
  of 
  the 
  assist- 
  

   ance 
  of 
  Mr. 
  A. 
  H. 
  Hamm, 
  who 
  twice 
  noticed 
  a 
  passing 
  

   euphrosyne 
  dipping 
  to 
  the 
  ground 
  and 
  examining 
  something 
  

   in 
  the 
  grass 
  and 
  debris. 
  On 
  going 
  to 
  the 
  place 
  we 
  found 
  

   one 
  of 
  the 
  wings 
  of 
  the 
  specimen 
  I 
  had 
  broken. 
  Considering 
  

   the 
  imiumerable 
  small 
  objects 
  of 
  similar 
  Imninosity 
  which 
  

   must 
  have 
  been 
  lying 
  about, 
  I 
  confess 
  I 
  am 
  unable 
  to 
  under- 
  

   stand 
  what 
  sense 
  except 
  that 
  of 
  colour 
  could 
  have 
  guided 
  

   the 
  butterflies 
  in 
  these 
  two 
  instances. 
  There 
  is 
  only 
  one 
  

   alternative, 
  viz. 
  scent. 
  But 
  the 
  dead 
  butterfly 
  was 
  many 
  

   years 
  old, 
  and 
  if 
  it 
  had 
  any 
  scent 
  it 
  was 
  more 
  Ukely 
  to 
  be 
  

   naphthahne 
  than 
  anything 
  else. 
  But 
  I 
  was 
  to 
  receive 
  a 
  

   remarkable 
  confirmation 
  of 
  this 
  observation 
  on 
  my 
  next 
  

   visit 
  to 
  the 
  wood. 
  I 
  again 
  observed 
  a 
  euphrosyne 
  hovering 
  

   over 
  something 
  on 
  the 
  ground, 
  and 
  on 
  going 
  to 
  investigate 
  

   I 
  discovered 
  a 
  large 
  bud 
  scale 
  of 
  exactly 
  the 
  golden 
  brown 
  

   colour 
  of 
  the 
  butterfly 
  itself. 
  Truly 
  this 
  seems 
  to 
  me 
  

   to 
  be 
  a 
  remarkable 
  performance 
  for 
  a 
  " 
  totally 
  colour-bhnd 
  " 
  

   organism. 
  

  

  Having 
  noted 
  the 
  superior 
  attraction 
  of 
  the 
  real 
  butterfly 
  

   over 
  the 
  paper 
  model, 
  a 
  fact 
  which 
  I 
  attribute 
  to 
  acuity 
  of 
  

   vision 
  at 
  close 
  quarters, 
  I 
  prepared 
  some 
  models 
  by 
  bleach- 
  

   ing 
  real 
  examples 
  of 
  the 
  butterfly, 
  dyeing 
  them 
  various 
  

   colours 
  and 
  replacing 
  the 
  spots 
  with 
  black 
  paint. 
  Some 
  of 
  

   my 
  "real 
  " 
  models 
  were 
  dyed 
  golden 
  brown 
  hke 
  the 
  normal 
  

   insect, 
  others 
  were 
  coloured 
  red, 
  blue, 
  greenish 
  yellow, 
  and 
  

   pale 
  buff. 
  Two 
  of 
  each 
  were 
  set 
  up 
  together 
  with 
  two 
  un- 
  

   treated 
  specimens. 
  In 
  half 
  an 
  hour 
  there 
  were 
  13 
  visits 
  

   to 
  the 
  naturally 
  coloured, 
  13 
  to 
  the 
  untreated, 
  and 
  none 
  at 
  

   all 
  to 
  the 
  others. 
  The 
  only 
  difference 
  in 
  the 
  behaviour 
  

   towards 
  the 
  dyed 
  and 
  the 
  untreated 
  examples 
  was 
  that 
  the 
  

   butterflies 
  actually 
  settled 
  on 
  the 
  latter, 
  but 
  only 
  hovered 
  

   over 
  the 
  others, 
  a 
  proceeding 
  again 
  attributable 
  to 
  the 
  

   slightly 
  unnatural 
  appearance, 
  at 
  close 
  quarters, 
  of 
  the 
  

   dyed 
  specimens. 
  

  

  Later 
  in 
  the 
  afternoon 
  the 
  butterflies 
  seemed 
  more 
  

   intent 
  on 
  feeding 
  than 
  love-making, 
  and 
  the 
  blue 
  bugle 
  

   flowers 
  were, 
  as 
  usual, 
  receiving 
  the 
  greater 
  share 
  of 
  their 
  

   attentions. 
  

  

  I 
  set 
  up 
  one 
  of 
  each 
  variety 
  of 
  my 
  models. 
  In 
  this 
  case 
  

   there 
  were 
  five 
  visits 
  to 
  the 
  naturally 
  coloured, 
  and 
  thirteen 
  

   to 
  the 
  untreated. 
  With 
  one 
  exception 
  none 
  of 
  the 
  other 
  

   models 
  was 
  noticed. 
  This 
  exception 
  was 
  a 
  blue 
  model 
  on 
  

  

  