﻿36 
  Dr. 
  H, 
  Eltringham 
  on 
  Butterfly 
  Vision. 
  

  

  and 
  dyed 
  grain, 
  which 
  are 
  very 
  interesting 
  and 
  ingenious. 
  

   He 
  experimented 
  with 
  larvae 
  of 
  Hyponomeuta 
  variabilis 
  

   by 
  placing 
  them 
  in 
  a 
  glass 
  vessel 
  with 
  parallel 
  sides, 
  and 
  

   found 
  that 
  for 
  the 
  most 
  part 
  they 
  crept 
  to 
  the 
  hd 
  nearest 
  

   the 
  hght. 
  If 
  a 
  strong 
  hght 
  were 
  arranged 
  in 
  one 
  half 
  and 
  

   a 
  weak 
  hght 
  in 
  the 
  other, 
  they 
  crept 
  into 
  the 
  bright 
  half. 
  

   When 
  a 
  spectrum 
  of 
  suitable 
  width 
  was 
  thrown 
  on 
  to 
  the 
  

   parallel-sided 
  glass 
  vessel, 
  they 
  crept 
  into 
  the 
  yellow 
  green. 
  

   If 
  the 
  vessel 
  were 
  moved 
  so 
  as 
  to 
  bring 
  those 
  in 
  the 
  yellow 
  

   green 
  into 
  the 
  red, 
  they 
  moved 
  again 
  into 
  the 
  yellow 
  

   green. 
  With 
  a 
  photometric 
  apparatus 
  consisting 
  of 
  a 
  red 
  

   and 
  blue 
  lamp 
  the 
  larvae 
  sought 
  the 
  blue, 
  even 
  when 
  to 
  the 
  

   human 
  eye 
  the 
  red 
  was 
  the 
  brighter 
  colour. 
  

  

  Larvae 
  of 
  Porthesia 
  chrysorrhoea 
  crept 
  to 
  the 
  most 
  

   brightly 
  lighted 
  part. 
  In 
  the 
  spectrum 
  they 
  moved 
  from 
  

   the 
  other 
  colours 
  into 
  the 
  yellow 
  green. 
  Larvae 
  of 
  Vanessa 
  io 
  

   behaved 
  in 
  a 
  similar 
  manner, 
  and 
  imagines 
  hatched 
  from 
  

   them 
  were 
  investigated 
  in 
  the 
  same 
  way. 
  In 
  the 
  spectrum 
  

   the 
  butterflies 
  fluttered 
  out 
  of 
  the 
  red, 
  blue, 
  and 
  violet 
  into 
  

   the 
  yeUow 
  green. 
  When 
  the 
  cage 
  was 
  hghted 
  half 
  with 
  

   bright 
  red, 
  half 
  with 
  dark 
  blue, 
  the 
  greater 
  number 
  went 
  

   into 
  the 
  blue. 
  " 
  All 
  my 
  larvae 
  behaved 
  as 
  they 
  must 
  

   behave 
  if 
  their 
  visual 
  powers 
  are 
  the 
  same 
  as, 
  or 
  similar 
  

   to, 
  those 
  of 
  a 
  totally 
  colour-bhnd 
  person. 
  There 
  is 
  nothing 
  

   comparable 
  to 
  the 
  colour 
  sense 
  of 
  the 
  normal 
  human 
  

   being." 
  With 
  other 
  experiments 
  he 
  shows 
  fairly 
  con- 
  

   clusively 
  that 
  mosquitoes 
  and 
  their 
  larvae 
  are 
  insensitive 
  

   to 
  red 
  hght, 
  whilst 
  still 
  further 
  investigations 
  show 
  that 
  

   Chalcids, 
  lady-birds, 
  and 
  house 
  flies 
  tend 
  to 
  move 
  from 
  

   other 
  colours 
  into 
  yellow 
  green. 
  

  

  Bees 
  were 
  experimented 
  on, 
  first 
  by 
  showing 
  that 
  they 
  

   were 
  strongly 
  positively 
  phototropic, 
  and 
  then 
  by 
  showing 
  

   that 
  they 
  moved 
  out 
  of 
  the 
  other 
  colours 
  into 
  the 
  yellow 
  

   green. 
  Given 
  the 
  choice 
  of 
  blue 
  and 
  red, 
  they 
  moved 
  out 
  

   of 
  the 
  red 
  into 
  the 
  blue. 
  With 
  the 
  photometric 
  apparatus 
  

   they 
  preferred 
  the 
  blue 
  to 
  the 
  red, 
  even 
  when 
  the 
  latter 
  

   appeared 
  to 
  the 
  operator 
  to 
  be 
  brighter 
  than 
  the 
  former. 
  

   By 
  increasing 
  still 
  further 
  the 
  red 
  hght 
  the 
  bees 
  moved 
  

   into 
  the 
  latter. 
  He 
  concludes 
  from 
  these 
  and 
  other 
  experi- 
  

   ments 
  that 
  the 
  bees 
  behaved 
  essentially 
  in 
  the 
  same 
  way 
  

   as 
  the 
  other 
  insects 
  he 
  experimented 
  upon. 
  

  

  After 
  quoting 
  at 
  considerable 
  length 
  the 
  experiments 
  of 
  

   Avebury, 
  Plateau, 
  Forel, 
  and 
  others, 
  Hess 
  thus 
  disposes 
  

   of 
  them 
  : 
  — 
  

  

  