﻿Dr. 
  H. 
  Eltringham 
  on 
  Butterfly 
  Vision. 
  45 
  

  

  Pierine 
  butterflies, 
  when 
  passing 
  each 
  other 
  sufi&ciently 
  

   closely, 
  turn 
  aside 
  and 
  carry 
  on 
  a 
  flirtation 
  in 
  the 
  air. 
  This 
  

   is 
  sight 
  and 
  not 
  scent, 
  since 
  different 
  species 
  will 
  behave 
  

   thus 
  until 
  closer 
  proximity 
  reveals 
  the 
  error. 
  I 
  observed 
  

   a 
  male 
  G. 
  rhmnni 
  fluttering 
  over 
  a 
  pansy 
  bed. 
  Except 
  for 
  

   its 
  well-known 
  pale 
  yellow 
  colour 
  it 
  would 
  have 
  passed 
  at 
  a 
  

   distance 
  for 
  P. 
  brassicae. 
  That 
  species 
  and 
  also 
  P. 
  rapae 
  

   were 
  flying 
  about 
  over 
  the 
  pansies, 
  and 
  whenever 
  they 
  

   came 
  within 
  each 
  other's 
  visual 
  field 
  the 
  usual 
  flirtation 
  

   ensued. 
  But 
  though 
  rhamni 
  and 
  the 
  other 
  Pierines 
  fre- 
  

   quently 
  came 
  so 
  near 
  together 
  as 
  to 
  be 
  almost 
  touching, 
  

   neither 
  took 
  any 
  notice 
  of 
  the 
  other. 
  This 
  is 
  the 
  more 
  

   remarkable 
  since 
  the 
  female 
  rhamni 
  is 
  nearly 
  white, 
  though 
  

   it 
  must 
  be 
  remembered 
  that 
  the 
  pairing 
  instinct 
  probably 
  

   does 
  not 
  develop 
  in 
  this 
  species 
  till 
  the 
  spring. 
  But 
  even 
  

   supposing 
  the 
  rhamni 
  was 
  all 
  intent 
  on 
  feeding, 
  the 
  brassicae 
  

   certainly 
  were 
  not, 
  and 
  under 
  the 
  circumstances 
  it 
  is 
  diffi- 
  

   cult 
  to 
  conceive 
  any 
  factor 
  other 
  than 
  colour 
  which 
  caused 
  

   them 
  to 
  ignore 
  the 
  rhamni. 
  

  

  In 
  the 
  early 
  part 
  of 
  1918 
  I 
  arranged 
  to 
  carry 
  out 
  some 
  

   experiments 
  with 
  B. 
  ewphrosyne, 
  which 
  is 
  common 
  in 
  woods 
  

   near 
  Oxford, 
  For 
  this 
  purpose 
  I 
  made 
  paper 
  models 
  of 
  

   the 
  butterfly 
  by 
  cutting 
  out 
  photographs 
  and 
  colouring 
  

   them. 
  Of 
  these 
  I 
  had 
  two 
  green, 
  two 
  blue, 
  two 
  crimson, 
  

   two 
  tawny 
  yellow 
  (the 
  natural 
  colour) 
  , 
  two 
  brown, 
  and 
  two 
  

   clear 
  pale 
  yellow. 
  In 
  all 
  cases 
  the 
  spots 
  were 
  black 
  as 
  in 
  

   the 
  real 
  fritillary. 
  In 
  addition 
  to 
  the 
  models 
  I 
  had 
  a 
  few 
  

   real 
  butterflies, 
  long 
  dead 
  and 
  dried. 
  

  

  In 
  the 
  first 
  place 
  the 
  superior 
  attraction 
  of 
  the 
  real 
  

   butterflies 
  was 
  very 
  noticeable. 
  The 
  live 
  fritillaries 
  dipped 
  

   at 
  and 
  examined 
  the 
  paper 
  models, 
  but 
  in 
  the 
  case 
  of 
  the" 
  

   real 
  ones 
  they 
  fluttered 
  over 
  them, 
  touched 
  them, 
  and 
  made 
  

   every 
  effort 
  to 
  obtain 
  some 
  response. 
  As 
  to 
  the 
  paper 
  

   models, 
  those 
  of 
  the 
  natural 
  colour 
  attracted 
  27 
  individuals, 
  

   red 
  models 
  attracted 
  18, 
  and 
  pale 
  yellow 
  2. 
  The 
  other 
  

   colours 
  were 
  not 
  noticed 
  at 
  all. 
  Note 
  that 
  the 
  only 
  colours 
  

   other 
  than 
  the 
  natural 
  shade 
  which 
  attracted 
  the 
  live 
  

   butterflies 
  were 
  those 
  which 
  might 
  have 
  been 
  confounded 
  

   with 
  the 
  real 
  colour. 
  So 
  far 
  as 
  luminosity 
  is 
  concerned, 
  

   the 
  brown 
  models 
  (a 
  rather 
  pale 
  brown) 
  about 
  equalled 
  the 
  

   naturally 
  coloured 
  models, 
  whilst 
  the 
  red, 
  though 
  suggestive 
  

   of 
  the 
  natural 
  colour, 
  had 
  much 
  less 
  luminosity. 
  

  

  While 
  pinning 
  up 
  my 
  models 
  I 
  broke 
  one 
  of 
  the 
  real 
  ones 
  

   and 
  threw 
  away 
  the 
  fragments. 
  This 
  accident 
  provided 
  

  

  