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  V. 
  Coispicuous 
  Effects 
  on 
  the 
  markings 
  and 
  colouring 
  

   of 
  Lepidoptera 
  caused 
  by 
  exposure 
  of 
  the 
  pupcB 
  

   to 
  different 
  temperature 
  conditions. 
  By 
  Frederic 
  

   Meerifield, 
  F.E.S. 
  

  

  [Read 
  December 
  Srd, 
  1890.] 
  

  

  Plate 
  IX. 
  

  

  In 
  reviewing 
  ■ 
  the 
  results 
  of 
  my 
  temperature 
  experiments 
  

   of 
  last 
  year, 
  I 
  found 
  some 
  which 
  could 
  not 
  altogether 
  be 
  

   explained 
  by 
  the 
  simple 
  theory 
  that 
  a 
  moderately 
  low 
  

   temperature, 
  applied 
  to 
  the 
  pupa 
  for 
  a 
  certain 
  minimum 
  

   period, 
  caused 
  in 
  the 
  imago 
  darkness 
  of 
  colouring 
  or 
  a 
  

   change 
  of 
  markings 
  in 
  a 
  definite 
  direction. 
  In 
  particular 
  

   they 
  indicated 
  that 
  the 
  part 
  of 
  the 
  pupal 
  period 
  during 
  

   which 
  the 
  temperature 
  was 
  applied 
  might 
  have 
  much 
  to 
  

   do 
  with 
  the 
  result, 
  and 
  therefore 
  I 
  determined 
  to 
  conduct 
  

   experiments 
  specially 
  directed 
  to 
  ascertain 
  whether 
  there 
  

   was 
  such 
  a 
  period, 
  and, 
  if 
  so, 
  to 
  define 
  it. 
  During 
  the 
  

   earlier 
  part 
  of 
  this 
  investigation 
  I 
  was 
  under 
  the 
  im- 
  

   pression, 
  derived 
  from 
  the 
  accounts 
  of 
  experiments 
  by 
  

   other 
  observers, 
  that 
  the 
  earliest 
  stage 
  of 
  the 
  pupal 
  period 
  

   was 
  the 
  sensitive 
  time, 
  and, 
  at 
  all 
  events, 
  that 
  the 
  last 
  

   few 
  days 
  were 
  of 
  little 
  importance 
  ; 
  and 
  accordingly, 
  

   in 
  certain 
  elaborate 
  experiments 
  which 
  I 
  made, 
  con- 
  

   sisting 
  of 
  the 
  forcing 
  of 
  pupae 
  immediately 
  after 
  pupation 
  

   for 
  periods 
  differing 
  by 
  a 
  few 
  days, 
  followed 
  by 
  cooling 
  

   for 
  different 
  periods 
  ; 
  and 
  the 
  converse, 
  — 
  i. 
  e. 
  cooling 
  

   succeeded 
  by 
  forcing, 
  — 
  I 
  generally 
  finished 
  in 
  both 
  cases 
  

   by 
  forcing 
  the 
  pupa 
  for 
  a 
  few 
  of 
  its 
  last 
  days, 
  as 
  a 
  matter 
  

   of 
  convenience, 
  in 
  order 
  to 
  get 
  it 
  out 
  of 
  the 
  way 
  for 
  

   further 
  work. 
  Some 
  facts 
  observed, 
  however, 
  during 
  the 
  

   early 
  part 
  of 
  the 
  past 
  summer, 
  led 
  me 
  to 
  suspect 
  that 
  

   for 
  certain 
  effects 
  the 
  later 
  days 
  of 
  the 
  pupal 
  period 
  were 
  

   especially 
  important, 
  and 
  I 
  instituted 
  accordingly 
  some 
  

   experiments 
  directed 
  to 
  ascertain 
  whether 
  it 
  was 
  so. 
  

  

  I 
  tried 
  these 
  with 
  the 
  two 
  species 
  I 
  had 
  before 
  found 
  

   sensitive 
  to 
  temperature, 
  — 
  namely, 
  S. 
  illustraria 
  {tetra- 
  

   lunaria) 
  and 
  E. 
  autumnaria, 
  — 
  and 
  the 
  results 
  fully 
  con- 
  

  

  TRANS. 
  ENT. 
  SOC. 
  LOND. 
  1891. 
  — 
  PART 
  I. 
  (MARCH.) 
  

  

  