﻿Dr. 
  H. 
  Eltringham 
  on 
  Butterfly 
  Vision. 
  35 
  

  

  may 
  well 
  have 
  been 
  developed 
  as 
  an 
  aid 
  to 
  conspicuousness, 
  

   as 
  opposed 
  to 
  attractiveness. 
  My 
  friend, 
  Dr. 
  Church, 
  who 
  

   has 
  made 
  a 
  special 
  study 
  of 
  floral 
  mechanism 
  and 
  the 
  

   visits 
  of 
  insects, 
  fully 
  agrees 
  that 
  a 
  flower 
  which 
  is 
  more 
  

   conspicuous 
  will 
  be 
  likely 
  to 
  be 
  visited 
  before 
  one 
  which 
  is 
  

   less 
  so. 
  From 
  the 
  experiments 
  of 
  Forel, 
  Avebury, 
  Plateau 
  

   and 
  others 
  we 
  have 
  evidence 
  that 
  insects, 
  especially 
  bees, 
  

   have 
  a 
  remarkable 
  memory, 
  not 
  only 
  for 
  locahty, 
  but 
  also 
  

   for 
  colour. 
  Thus 
  a 
  bee 
  which 
  has 
  been 
  given 
  honey 
  on 
  a 
  

   blue 
  paper 
  rapidly 
  associated 
  the 
  idea 
  of 
  honey 
  and 
  blue, 
  

   or 
  whatever 
  sensation 
  the 
  blue 
  colour 
  may 
  convey 
  to 
  it. 
  

   Lest 
  it 
  should 
  be 
  supposed 
  that 
  bees 
  are 
  specially 
  asso- 
  

   ciated 
  with 
  blue, 
  we 
  may 
  instance 
  another 
  experiment 
  of 
  

   Lord 
  Avebury. 
  Equal-sized 
  discs 
  of 
  red, 
  yellow, 
  green, 
  

   and 
  blue 
  were 
  provided, 
  and 
  honey 
  was 
  placed 
  on 
  the 
  red 
  

   disc. 
  A 
  marked 
  bee 
  was 
  also 
  placed 
  on 
  the 
  red 
  disc. 
  

   After 
  the 
  bee 
  had 
  fed, 
  gone 
  back 
  to 
  the 
  hive 
  and 
  returned 
  

   a 
  few 
  times, 
  the 
  red 
  disc 
  was 
  replaced 
  by 
  a 
  blue 
  disc 
  with 
  

   honey, 
  and 
  another 
  red 
  disc 
  was 
  placed 
  near, 
  but 
  without 
  

   honey. 
  When 
  the 
  bee 
  returned 
  it 
  went 
  to 
  the 
  red 
  disc 
  

   and 
  searched 
  for 
  the 
  honey 
  it 
  had 
  been 
  accustomed 
  to 
  find 
  

   thereon. 
  Nor 
  could 
  it 
  find 
  the 
  honey 
  on 
  the 
  blue 
  disc, 
  

   though 
  this 
  was 
  close 
  at 
  hand, 
  showing 
  a 
  defective 
  sense 
  of 
  

   smell. 
  Numerous 
  further 
  experiments 
  showed 
  that 
  bees 
  

   rarely 
  confuse 
  colours 
  except 
  blue 
  and 
  green. 
  Forel 
  tried 
  

   the 
  same 
  experiment 
  in 
  the 
  opposite 
  order, 
  when 
  the 
  bee 
  

   always 
  went 
  to 
  the 
  blue 
  disc, 
  and 
  even 
  to 
  a 
  strip 
  of 
  

   blue 
  paper, 
  showing 
  that 
  it 
  was 
  not 
  the 
  form 
  which 
  

   guided 
  it. 
  

  

  More 
  valuable 
  evidence 
  than 
  all 
  these 
  observations 
  is 
  

   given 
  by 
  Forel 
  when 
  he 
  describes 
  how 
  a 
  bee, 
  fed 
  on 
  blue 
  

   paper, 
  afterwards 
  sought 
  out 
  and 
  examined 
  all 
  the 
  pieces 
  

   of 
  blue 
  paper 
  in 
  various 
  corners 
  of 
  the 
  room, 
  in 
  whatever 
  

   surroundings 
  they 
  happened 
  to 
  be. 
  The 
  latter 
  part 
  of 
  the 
  

   sentence 
  discounts 
  entirely 
  the 
  mere 
  luminosity 
  value 
  of 
  

   the 
  blue 
  paper. 
  

  

  Before 
  describing 
  my 
  own 
  experiments 
  which 
  have 
  been 
  

   made 
  with 
  butterflies, 
  I 
  must 
  briefly 
  review 
  the 
  work 
  of 
  

   Hess, 
  referred 
  to 
  in 
  the 
  flrst 
  part 
  of 
  this 
  paper, 
  from 
  which 
  

   that 
  author 
  deduces 
  the 
  opinion 
  that 
  insects, 
  bees 
  and 
  

   butterflies 
  included, 
  are 
  totally 
  colour-bhnd. 
  In 
  attempt- 
  

   ing 
  to 
  show 
  that 
  his 
  results 
  with 
  these 
  insects 
  are 
  incon- 
  

   clusive 
  I 
  do 
  not 
  wish 
  to 
  detract 
  from 
  the 
  value 
  of 
  his 
  

   research 
  with 
  other 
  animals, 
  especially 
  those 
  with 
  birds 
  

  

  