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  xiii 
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  "24, 
  Vernon 
  Terrace, 
  Brighton, 
  

   20th 
  April, 
  1891. 
  

   My 
  Dear 
  Sir, 
  

  

  As 
  I 
  fear 
  that 
  I 
  shall 
  be 
  unable 
  to 
  be 
  present 
  

   at 
  the 
  meeting 
  of 
  the 
  Society 
  on 
  the 
  6th 
  May, 
  I 
  write 
  to 
  ask 
  

   you 
  to 
  be 
  good 
  enough 
  to 
  read 
  this 
  letter, 
  to 
  correct 
  some 
  

   surprising 
  errors 
  into 
  which 
  Mr. 
  C. 
  Fenn, 
  if 
  he 
  is 
  correctly 
  

   reported, 
  has 
  fallen. 
  That 
  gentleman 
  is 
  reported, 
  in 
  the 
  

   ' 
  Proceedings 
  '* 
  of 
  the 
  Entom. 
  Soc. 
  of 
  1st 
  April, 
  to 
  have 
  said, 
  

   with 
  reference 
  to 
  a 
  brood 
  of 
  T. 
  instabilis 
  which 
  he 
  exhibited, 
  

   including 
  some 
  abnormally 
  pale 
  examples, 
  that 
  they 
  ' 
  had 
  

   been 
  bred 
  during 
  the 
  recent 
  severe 
  weather,' 
  and 
  that, 
  

   '•according 
  to 
  Mr. 
  Merrifield's 
  theory, 
  they 
  ought 
  to 
  have 
  

   been 
  very 
  dark.' 
  Further, 
  the 
  same 
  gentleman 
  is 
  re- 
  

   ported 
  to 
  have 
  stated, 
  at 
  the 
  South 
  London 
  Entomological 
  

   Society's 
  meeting 
  of 
  the 
  9th 
  April, 
  of 
  the 
  same 
  brood, 
  that 
  

   these 
  pale 
  varieties 
  ' 
  completely 
  overthrow 
  Mr. 
  Merrifield's 
  

   suggestion 
  that 
  exposure 
  to 
  great 
  cold 
  just 
  before 
  emergence 
  

   tended 
  to 
  produce 
  dark 
  coloration, 
  as 
  these 
  were 
  exposed 
  to 
  

   very 
  extreme 
  cold.' 
  If 
  Mr. 
  Fenn 
  will 
  be 
  so 
  good 
  as 
  to 
  refer 
  

   to 
  my 
  views, 
  which 
  are 
  to 
  be 
  found 
  recorded 
  in 
  the 
  ' 
  Trans- 
  

   actions 
  ' 
  of 
  the 
  Society, 
  he 
  will 
  see 
  that 
  he 
  has 
  entirely 
  mis- 
  

   apprehended 
  them. 
  I 
  have 
  never 
  suggested, 
  or 
  imagined, 
  

   that 
  coloration 
  is, 
  in 
  all 
  species 
  of 
  Lepidoptera, 
  affected 
  by 
  

   exposure 
  of 
  the 
  pupa 
  to 
  a 
  low 
  temperature. 
  What 
  I 
  have 
  

   stated 
  (and 
  found, 
  by 
  the 
  invariable 
  result 
  in 
  many 
  broods, 
  

   some 
  as 
  healthy 
  as 
  could 
  be 
  seen) 
  is, 
  that 
  exposure 
  of 
  the 
  

   pupa, 
  shortly 
  (not 
  immediately) 
  before 
  emergence, 
  to 
  a 
  low 
  

   temperature 
  (defined 
  in 
  the 
  next 
  sentence) 
  does 
  tend 
  to 
  pro- 
  

   duce 
  darkness 
  of 
  coloration 
  in 
  S. 
  illustmria, 
  both 
  summer 
  and 
  

   spring 
  emergence, 
  and 
  in 
  E. 
  autuwnaria, 
  and 
  probably 
  in 
  

   many 
  other 
  species 
  (Ent. 
  Trans., 
  1891, 
  pp. 
  164, 
  167). 
  This 
  

   of 
  course 
  is 
  quite 
  consistent 
  with 
  T. 
  instabilis 
  not 
  being 
  so 
  

   affected. 
  Secondly, 
  as 
  to 
  the 
  degree 
  of 
  low 
  temperature 
  

   which 
  is 
  efficacious, 
  I 
  have 
  expressly 
  stated 
  ' 
  that 
  in 
  the 
  

   species 
  operated 
  on, 
  a 
  difference 
  between 
  80° 
  and 
  67° 
  is 
  

  

  * 
  See 
  reports 
  of 
  ' 
  Proceedings 
  ' 
  of 
  April 
  meeting 
  of 
  the 
  Ento. 
  Soc. 
  in 
  

   the 
  'Athenaeum,' 
  'Nature,' 
  ' 
  The 
  Zoologist,' 
  the 
  'Entomologist,' 
  the 
  

   'Entomologist's 
  Monthly 
  Magazine,' 
  &c. 
  

  

  