﻿the 
  markimis 
  and 
  colouiiitg 
  of 
  Lejndoptera. 
  157 
  

  

  refrigerator, 
  it 
  ranged 
  from 
  about 
  35° 
  to 
  39°) 
  ; 
  the 
  

   "cooling" 
  temperature, 
  being 
  that 
  of 
  the 
  interior 
  of 
  

   the 
  refrigerator, 
  ranged 
  from 
  39° 
  to 
  55°, 
  averaging 
  in 
  

   summer 
  about 
  47° 
  ; 
  the 
  forcing 
  temperature 
  was 
  about 
  

   80°. 
  The 
  "out-door" 
  and 
  "room" 
  or 
  "in-door" 
  tem- 
  

   perature, 
  especially 
  the 
  former, 
  varied, 
  but 
  I 
  give 
  the 
  

   amount 
  of 
  it, 
  as 
  far 
  as 
  practicable, 
  in 
  each 
  case. 
  

  

  I 
  may 
  premise 
  that 
  (with 
  the 
  aid 
  of 
  an 
  assistant) 
  

   I 
  have 
  tried 
  many 
  more 
  experiments 
  than 
  I 
  describe 
  

   here; 
  some 
  necessarily 
  gave 
  negative 
  or 
  inconclusive 
  

   results, 
  and 
  with 
  these, 
  though 
  useful 
  to 
  myself, 
  I 
  will 
  

   not 
  trouble 
  the 
  Society. 
  

  

  It 
  will 
  perhaps 
  be 
  remembered 
  that 
  last 
  year's 
  experi- 
  

   ments 
  showed 
  that 
  a 
  naturally 
  rather 
  dark-coloured 
  

   brood 
  of 
  illustraria 
  of 
  the 
  summer 
  emergence, 
  when 
  

   subjected 
  to 
  icing 
  for 
  periods 
  successively 
  lengthened 
  

   by 
  fourteen 
  days, 
  produced 
  moths 
  darker 
  in 
  colour, 
  and, 
  

   after 
  a 
  period 
  averaging 
  twelve 
  weeks 
  or 
  more, 
  for 
  the 
  

   most 
  part 
  distinctly 
  altered 
  in 
  markings 
  so 
  as 
  to 
  

   approach 
  those 
  of 
  the 
  spring 
  emergence. 
  This 
  year 
  

   I 
  determined 
  to 
  experiment 
  with 
  broods 
  from 
  a 
  race 
  

   selected 
  for 
  its 
  tendency 
  to 
  light 
  orange 
  or 
  chestnut 
  

   colouring, 
  which, 
  to 
  give 
  it 
  a 
  short 
  distinctive 
  name, 
  

   I 
  called 
  "red," 
  and 
  which, 
  being 
  of 
  a 
  lighter 
  colour, 
  

   would 
  be 
  better 
  adapted 
  to 
  show 
  dark 
  effects. 
  

  

  Experiments 
  on 
  Illustraria. 
  

  

  For 
  this 
  piTrpose 
  I 
  took 
  two 
  broods 
  of 
  the 
  spring 
  larvae 
  of 
  the 
  

   ' 
  red" 
  race, 
  forcing 
  the 
  larvas 
  to 
  get 
  them 
  out 
  of 
  the 
  way 
  of 
  other 
  

   experiments, 
  and 
  they 
  pupated 
  between 
  10th 
  and 
  25th 
  June. 
  The 
  

   first 
  of 
  these 
  I 
  called 
  " 
  red 
  c" 
  ; 
  it 
  produced 
  me 
  about 
  59 
  pupae. 
  

  

  Ten 
  of 
  these 
  "red 
  c," 
  taken 
  promiscuously 
  fi:om 
  day 
  to 
  day, 
  

   were 
  forced 
  at 
  the 
  temperature 
  of 
  80°, 
  and 
  produced 
  eight 
  moths, 
  

   all 
  of 
  the 
  light 
  warm 
  tint 
  proper 
  to 
  the 
  race, 
  and 
  in 
  all 
  respects 
  

   of 
  marking 
  and 
  colouring 
  belonging 
  to 
  the 
  summer 
  type. 
  Two 
  of 
  

   them 
  are 
  shown 
  as 
  Figs. 
  3 
  and 
  4 
  in 
  the 
  Plate. 
  

  

  The 
  rest 
  were 
  iced 
  from 
  day 
  to 
  day 
  as 
  they 
  hardened, 
  and 
  on 
  

   the 
  14th 
  Sept., 
  i. 
  e. 
  after 
  about 
  twelve 
  weeks' 
  icing, 
  were 
  taken 
  out 
  

   of 
  the 
  ice-box 
  and 
  subjected 
  to 
  differential 
  treatment 
  as 
  follows 
  : 
  — 
  

  

  (1) 
  Icing 
  twelve 
  iveehs 
  followed 
  by 
  forcing. 
  — 
  Twenty-three 
  were 
  

   thus 
  forced, 
  and 
  after 
  five 
  days' 
  forcing 
  they 
  began 
  to 
  emerge. 
  

   Nine 
  came 
  out 
  on 
  the 
  fifth 
  day 
  ; 
  the 
  rest 
  were 
  then 
  beginning 
  to 
  

   show 
  the 
  colour 
  of 
  the 
  perfect 
  insect, 
  and 
  would 
  doubtless 
  have 
  

  

  