﻿Dr. 
  H. 
  Eltringham 
  on 
  Butterfly 
  Vision. 
  39 
  

  

  ones 
  had 
  proved 
  disappointing. 
  Models 
  distinctly 
  wrongly- 
  

   coloured 
  were 
  disregarded. 
  The 
  sense 
  of 
  smell 
  was 
  shown 
  

   in 
  these 
  cases 
  to 
  have 
  little 
  apparent 
  influence. 
  From 
  the 
  

   position 
  adopted 
  by 
  the 
  male 
  relatively 
  to 
  the 
  female 
  it 
  

   was 
  found 
  that 
  the 
  male 
  could 
  recognise 
  the 
  head 
  from 
  the 
  

   tail 
  of 
  the 
  model 
  only 
  at 
  a 
  distance 
  of 
  about 
  two 
  to 
  four 
  

   inches, 
  whilst 
  the 
  wrong 
  colour 
  seemed 
  to 
  be 
  recognised 
  

   at 
  six 
  feet, 
  and 
  abnormal 
  size 
  at 
  from 
  H 
  to 
  4| 
  feet. 
  

  

  From 
  their 
  behaviour 
  in 
  trying 
  to 
  pair 
  with 
  paper 
  

   models 
  fluttering 
  in 
  the 
  wind, 
  it 
  was 
  evident 
  that 
  the 
  differ- 
  

   ence 
  of 
  texture 
  between 
  the 
  paper 
  and 
  the 
  real 
  wing 
  was 
  

   not 
  recognised. 
  

  

  As 
  some 
  evidence 
  of 
  colour 
  perception 
  Seitz 
  remarks 
  

   that 
  the 
  vertebrate 
  eye 
  can 
  see 
  red 
  further 
  away 
  than 
  

   blue. 
  He 
  observed 
  in 
  South 
  America 
  certain 
  Pierine 
  

   butterflies 
  flying 
  at 
  some 
  height 
  over 
  a 
  mass 
  of 
  blue 
  flower- 
  

   ing 
  shrubs, 
  amongst 
  which 
  there 
  were 
  isolated 
  flowers 
  of 
  

   a 
  brilhant 
  red. 
  The 
  butterflies 
  precipitated 
  themselves 
  

   on 
  the 
  red 
  flowers 
  first, 
  afterwards 
  visiting 
  the 
  blue 
  ones. 
  

   This 
  was 
  the 
  more 
  remarkable 
  as 
  the 
  blue-flowered 
  plant 
  

   was 
  the 
  food 
  plant 
  of 
  the 
  larva 
  and 
  might 
  have 
  been 
  

   supposed 
  to 
  attract 
  the 
  insects 
  first. 
  

  

  I 
  have 
  not 
  quoted 
  these 
  observations 
  because 
  they 
  carry 
  

   us 
  very 
  much 
  further, 
  but 
  they 
  seem 
  to 
  be 
  the 
  only 
  experi- 
  

   ments 
  of 
  the 
  kind 
  so 
  far 
  recorded. 
  

  

  My 
  own 
  researches 
  have 
  not 
  gone 
  so 
  far 
  as 
  I 
  could 
  wish. 
  

   Much 
  that 
  was 
  done 
  in 
  1917 
  suggested 
  other 
  lines 
  of 
  

   investigation 
  by 
  which 
  I 
  hoped 
  to 
  profit 
  in 
  1918. 
  I 
  had 
  

   special 
  flower-beds 
  planted 
  and 
  other 
  preparations 
  made, 
  

   only 
  to 
  be 
  disappointed 
  by 
  the 
  total 
  disappearance 
  of 
  all 
  

   butterflies 
  at 
  the 
  end 
  of 
  August. 
  The 
  absence 
  of 
  V. 
  tirticae 
  

   was 
  especially 
  noticeable, 
  since 
  in 
  the 
  garden 
  where 
  I 
  had 
  

   arranged 
  my 
  flowers 
  this 
  species 
  usually 
  flies 
  in 
  great 
  

   numbers 
  well 
  into 
  October. 
  

  

  However, 
  while 
  not 
  claiming 
  the 
  essential 
  virtue 
  of 
  being 
  

   a 
  " 
  scientific 
  chromatologist," 
  I 
  may 
  give 
  my 
  results 
  so 
  

   far 
  as 
  they 
  go, 
  and 
  leave 
  others 
  to 
  judge 
  of 
  the 
  extent 
  to 
  

   which 
  they 
  throw 
  light 
  on 
  the 
  subject. 
  

  

  It 
  having 
  been 
  suggested 
  that 
  butterflies 
  are 
  either 
  

   " 
  short 
  " 
  in 
  the 
  red, 
  or, 
  if 
  totally 
  colour-bhnd, 
  then 
  red- 
  

   bhnd, 
  I 
  endeavoured 
  to 
  prove 
  or 
  disprove 
  this 
  theory 
  in 
  

   the 
  following 
  way. 
  I 
  obtained 
  a 
  dye 
  which 
  I 
  ascertained, 
  

   by 
  means 
  of 
  the 
  spectroscope, 
  transmitted 
  only 
  red 
  rays. 
  

   I 
  am 
  unable 
  to 
  give 
  its 
  composition, 
  as 
  it 
  is 
  a 
  proprietary 
  

  

  