﻿158 
  Mr. 
  F. 
  MeiTilield 
  on 
  conspicuous 
  effects 
  on 
  

  

  emerged 
  on 
  that 
  day 
  or 
  in 
  the 
  next 
  day 
  or 
  two. 
  Ten 
  of 
  them 
  

   were 
  placed 
  at 
  the 
  " 
  cooling" 
  temperature, 
  then 
  averaging 
  43°, 
  and 
  

   five 
  of 
  these, 
  besides 
  some 
  cripples, 
  emerged 
  in 
  from 
  two 
  to 
  eight 
  

   days. 
  Of 
  the 
  remaining 
  thirteen, 
  eleven 
  emerged 
  uncrippled 
  or 
  

   nearly 
  so. 
  There 
  is 
  no 
  material 
  difference 
  between 
  those 
  which 
  

   were 
  thus 
  differently 
  treated. 
  They 
  show 
  an 
  interesting 
  combination 
  

   of 
  colouring 
  and 
  markings, 
  viz. 
  a 
  colouring 
  approximating 
  to 
  that 
  

   of 
  the 
  summer 
  emergence 
  with, 
  in 
  all 
  but 
  2 
  or 
  3 
  individuals, 
  the 
  

   marJiings 
  proper 
  to 
  the 
  spring 
  emergence. 
  Nos. 
  5 
  and 
  6 
  in 
  the 
  

   Plate 
  are 
  tj'pical 
  examples 
  of 
  them. 
  

  

  This 
  experiment 
  seems 
  to 
  show 
  (1) 
  that 
  though 
  icing 
  the 
  summer 
  

   pupae 
  for 
  twelve 
  weeks 
  develops- 
  in 
  general 
  the 
  spring 
  markings, 
  

   yet 
  that 
  after 
  the 
  change 
  in 
  markings 
  has 
  thus 
  been 
  effected, 
  

   forcing 
  during 
  the 
  last 
  five 
  days 
  brings 
  out 
  the 
  moths 
  in 
  the 
  

   characteristic 
  summer 
  colouring; 
  (2) 
  that 
  exposure 
  to 
  a 
  low 
  tem- 
  

   perature 
  (about 
  43°) 
  when 
  the 
  insect 
  is 
  in 
  the 
  ultimate 
  pupal 
  

   stage, 
  i. 
  e. 
  when 
  the 
  colours 
  of 
  the 
  imago 
  are 
  beginning 
  to 
  show, 
  

   makes 
  no 
  difference. 
  

  

  (6) 
  Icing 
  twelve 
  weeks, 
  followed 
  by 
  a 
  loiu 
  or 
  moderate 
  tem- 
  

   perattire. 
  — 
  The 
  remainder 
  of 
  the 
  "rede," 
  twenty-six 
  in 
  number, 
  

   were 
  on 
  the 
  14th 
  Sept. 
  xalaced 
  out 
  of 
  doors, 
  and 
  all 
  emerged 
  in 
  

   from 
  nine 
  to 
  sixteen 
  days, 
  the 
  temperature 
  at 
  8 
  a.m. 
  averaging 
  

   about 
  57°. 
  Thej 
  showed 
  not 
  only 
  the 
  sjjring 
  markings, 
  but, 
  as 
  

   will 
  be 
  seen 
  in 
  the 
  Plate, 
  figs. 
  7 
  and 
  8, 
  a 
  dark 
  colour, 
  in 
  some 
  

   cases 
  closely 
  approximating 
  to 
  that 
  of 
  the 
  spring 
  emergence. 
  With 
  

   two 
  or 
  three 
  exceptions, 
  all 
  are 
  darker 
  than 
  any 
  of 
  those 
  in 
  the 
  

   preceding 
  experiment, 
  and 
  most 
  are 
  much 
  darker. 
  We 
  thus 
  have 
  

   the 
  spring 
  markings 
  and 
  a 
  close 
  approximation 
  to 
  the 
  sjpring 
  

   colouring 
  produced 
  by 
  subjecting 
  to 
  a 
  moderately 
  low 
  temperature, 
  

   averaging 
  57° 
  at 
  8 
  a.m., 
  pupee 
  the 
  moths 
  from 
  which 
  would 
  other- 
  

   wise 
  have 
  shown 
  the 
  markings 
  and 
  colouring 
  proper 
  to 
  the 
  summer 
  

   emergence. 
  

  

  Three 
  of 
  the 
  twenty-six 
  were, 
  after 
  eight 
  days 
  of 
  the 
  out-door 
  

   temperature 
  "cooled" 
  (43°) 
  emerging 
  respectively 
  in 
  12, 
  16 
  and 
  30 
  

   days 
  ; 
  but 
  this 
  treatment 
  made 
  no 
  appreciable 
  difference 
  in 
  their 
  

   appearance. 
  

  

  (c) 
  The 
  same, 
  succeeded 
  by 
  forcing 
  during 
  the 
  ultimate 
  j^eriod. 
  

   — 
  Four 
  of 
  the 
  twenty-six 
  were 
  after 
  eight 
  days 
  forced, 
  and 
  three 
  of 
  

   them 
  emerged 
  in 
  from 
  1^ 
  to 
  2^ 
  days 
  ; 
  in 
  two 
  of 
  these 
  there 
  is 
  a 
  

   change 
  in 
  a 
  direction 
  towards 
  the 
  summer 
  colouring. 
  

  

  Taken 
  as 
  a 
  whole, 
  the 
  experiments 
  on 
  " 
  red 
  c 
  " 
  seem 
  to 
  show 
  

   that 
  the 
  ordinary 
  out-door 
  temperature 
  of 
  a 
  rather 
  warm 
  Sep- 
  

   tember, 
  which, 
  taken 
  at 
  8 
  a.m. 
  during 
  the 
  time 
  of 
  exposm-e, 
  

   averaged 
  about 
  57°, 
  is 
  as 
  efficacious 
  to 
  produce 
  a 
  dark 
  colouring 
  as 
  

  

  