﻿164 
  Mr. 
  F. 
  Merrifield 
  on 
  consjncuous 
  effects 
  on 
  

  

  (q) 
  B. 
  quercus. 
  — 
  Experiments 
  with 
  this 
  species 
  have 
  not 
  yet 
  

   been 
  brought 
  to 
  a 
  conclusion, 
  but 
  I 
  have 
  had 
  out 
  a 
  number 
  of 
  the 
  

   var. 
  callunce, 
  from 
  Aberdeen 
  and 
  Perth, 
  at 
  a 
  forcing 
  temperature 
  ; 
  

   and 
  these 
  are 
  certainly 
  lighter 
  in 
  colouring 
  than 
  the 
  ordinary 
  

   callunce, 
  and 
  not 
  greatly 
  to 
  be 
  distinguished 
  from 
  the 
  ordinary 
  

   B. 
  quercus. 
  

  

  General 
  Conclusions. 
  

  

  All 
  the 
  experiments, 
  so 
  far, 
  seem 
  to 
  point 
  to 
  the 
  

   conclusions 
  : 
  — 
  

  

  1. 
  That 
  both 
  the 
  markings 
  and 
  the 
  colouring 
  of 
  the 
  

   perfect 
  insect 
  may 
  be 
  materially 
  affected 
  by 
  the 
  tem- 
  

   perature 
  to 
  which 
  the 
  pupa 
  is 
  exposed. 
  

  

  2. 
  That 
  the 
  markings 
  are 
  chiefly 
  affected 
  by 
  long- 
  

   continued 
  exposure, 
  probably 
  previous 
  to 
  the 
  time 
  when 
  

   the 
  insect 
  has 
  begun 
  to 
  go 
  through 
  the 
  changes 
  between 
  

   the 
  central 
  inactive 
  stage 
  and 
  emergence. 
  

  

  3. 
  That 
  the 
  colouring 
  is 
  chiefly 
  affected 
  during 
  the 
  

   penultimate 
  pupal 
  stage, 
  i. 
  e., 
  before 
  the 
  colouring 
  of 
  

   the 
  imago 
  begins 
  to 
  show. 
  

  

  4. 
  That 
  a 
  low 
  temperature 
  during 
  this 
  penultimate 
  

   stage 
  causes 
  darkness, 
  a 
  high 
  temperature 
  during 
  the 
  

   same 
  period 
  having 
  the 
  opposite 
  effect. 
  

  

  5. 
  That, 
  in 
  the 
  species 
  operated 
  on, 
  a 
  difference 
  

   between 
  80° 
  and 
  57° 
  is 
  sufficient 
  to 
  produce 
  the 
  extreme 
  

   variation 
  in 
  darkness 
  caused 
  by 
  temperature, 
  a 
  further 
  

   lowering 
  of 
  the 
  temperature 
  having 
  no 
  further 
  effect 
  on 
  

   it. 
  (Taken 
  in 
  connexion 
  with 
  the 
  others, 
  previously 
  

   published, 
  these 
  experiments 
  show 
  further 
  that 
  nearly 
  

   the 
  full 
  effect 
  in 
  colouring 
  may 
  be 
  produced 
  by 
  a 
  much 
  

   narrower 
  range 
  of 
  temperature, 
  viz., 
  from 
  76° 
  or 
  80° 
  to 
  

   65° 
  in 
  autumnaria, 
  from 
  73° 
  to 
  60° 
  in 
  iUustmria.) 
  

  

  6. 
  That 
  in 
  these 
  species 
  dr3'ness 
  or 
  moisture 
  during 
  

   the 
  pupal 
  period, 
  whether 
  during 
  a 
  low 
  temperature 
  or 
  

   a 
  high 
  one, 
  has 
  little 
  or 
  no 
  effect 
  on 
  the 
  colouring 
  of 
  the 
  

   imago. 
  

  

  These 
  conclusions 
  may 
  be 
  treated 
  as 
  established 
  as 
  

   regards 
  illustraria 
  and 
  autumnaria. 
  Of 
  course 
  a 
  much 
  

   larger 
  number 
  of 
  species 
  should 
  be 
  tried 
  before 
  they 
  can 
  

   be 
  treated 
  as 
  applicable 
  generally. 
  I 
  do 
  not 
  doubt 
  that 
  

   protective 
  requirements, 
  hereditary 
  tendencies, 
  and 
  

   probably 
  other 
  climatic 
  conditions 
  than 
  those 
  of 
  tem- 
  

   perature, 
  and 
  other 
  causes 
  that 
  need 
  not 
  be 
  enumerated, 
  

   have 
  their 
  part 
  in 
  affecting 
  colour 
  ; 
  but 
  the 
  facts 
  

  

  