﻿TRANSACTIONS 
  

  

  OF 
  THE 
  

  

  ENTOMOLOGICAL 
  SOCIETY 
  

  

  OF 
  

  

  LONDON 
  

  

  For 
  the 
  Year 
  1919. 
  

  

  I. 
  Butterfly 
  Vision. 
  By 
  H. 
  Eltringham, 
  M.A., 
  D.Sc.,F.Z.S. 
  

  

  [Read 
  December 
  4th, 
  1918.] 
  

  

  Plates 
  I-V. 
  

  

  So 
  much 
  has 
  already 
  been 
  written 
  on 
  the 
  structure 
  and 
  

   function 
  of 
  the 
  compound 
  or 
  facetted 
  eye 
  of 
  Arthropods, 
  

   that 
  the 
  worker 
  who 
  is 
  unequipped 
  with 
  a 
  profound 
  know- 
  

   ledge 
  of 
  optics, 
  mathematics 
  and 
  other 
  sciences, 
  may 
  well 
  

   feel 
  some 
  hesitancy 
  in 
  adding 
  to 
  the 
  already 
  voluminous 
  

   literature 
  of 
  the 
  subject. 
  Nevertheless, 
  since 
  most 
  works 
  

   on 
  insects 
  in 
  general 
  give 
  but 
  a 
  very 
  imperfect 
  summary 
  

   of 
  existing 
  knowledge, 
  whilst 
  comparatively 
  few 
  papers 
  

   on 
  the 
  insect 
  eye 
  are 
  written 
  in 
  Enghsh, 
  it 
  is 
  hoped 
  that 
  

   the 
  observations 
  here 
  recorded 
  will 
  not 
  be 
  regarded 
  as 
  

   altogether 
  superfluous. 
  

  

  If 
  my 
  examination 
  of 
  the 
  matter 
  appears 
  to 
  have 
  resulted 
  

   in 
  but 
  little 
  that 
  is 
  new, 
  at 
  least 
  I 
  can 
  claim 
  to 
  have 
  

   repeated 
  many 
  of 
  the 
  known 
  experiments 
  and 
  thus 
  helped 
  

   to 
  remove 
  at 
  least 
  some 
  of 
  the 
  uncertainty 
  which 
  has 
  

   hitherto 
  tended 
  to 
  make 
  the 
  subject 
  of 
  insect 
  vision 
  an 
  

   unstable 
  compound 
  of 
  opposing 
  theories. 
  My 
  attention 
  

   was 
  first 
  called 
  to 
  the 
  subject 
  by 
  the 
  articles 
  on 
  the 
  sense 
  

   of 
  sight 
  written 
  by 
  Hess, 
  in 
  the 
  " 
  Handbuch 
  der 
  vergleich- 
  

   ender 
  Physiologie," 
  in 
  which 
  he 
  describes 
  very 
  extensive 
  

   and 
  elaborate 
  experiments 
  on 
  animal 
  vision. 
  As 
  the 
  result 
  

   of 
  these 
  he 
  announces 
  that 
  all 
  insects, 
  or 
  at 
  least 
  those 
  on 
  

   which 
  he 
  experimented, 
  are 
  totally 
  colour-bhnd. 
  

  

  How 
  many 
  of 
  us 
  have 
  not 
  been 
  first 
  attracted 
  to 
  the 
  

   study 
  of 
  insects 
  by 
  their 
  beautiful 
  colours 
  and 
  their 
  asso- 
  

  

  TRANS. 
  ENT. 
  SOC. 
  LOND. 
  1919. 
  — 
  PARTS 
  I, 
  II. 
  (JULY) 
  B 
  

  

  