﻿160 
  Mr. 
  F. 
  Merrifield 
  on 
  conspicuous 
  effects 
  on 
  

  

  parents 
  which 
  had 
  been 
  forced 
  all 
  through. 
  There 
  is 
  httle 
  ditference 
  

   between 
  the 
  females 
  Nos. 
  3, 
  4, 
  5 
  and 
  6, 
  two 
  of 
  which 
  are 
  slightly 
  

   crippled; 
  in 
  general 
  they 
  are 
  nearer 
  to 
  the 
  spring 
  than 
  the 
  

   summer 
  tj^pe 
  of 
  colouring. 
  

  

  (e) 
  Moderately 
  loio 
  temiierature 
  for 
  different 
  2:)eriods 
  foUowed 
  

   hy 
  forcing. 
  — 
  With 
  the 
  second 
  division, 
  consisting 
  of 
  eight 
  males 
  

   and 
  eight 
  females, 
  the 
  converse 
  experiment 
  was 
  tried 
  by 
  placing 
  

   the 
  pupae, 
  when 
  taken 
  from 
  the 
  ice, 
  in 
  the 
  open 
  air, 
  and 
  removing 
  

   them 
  at 
  intervals 
  to 
  the 
  forcing-box. 
  The 
  intervals 
  were 
  of 
  two 
  or 
  

   three 
  days, 
  instead 
  of 
  a 
  single 
  day, 
  in 
  order 
  to 
  make 
  allowance 
  for 
  

   the 
  slower 
  rate 
  of 
  progi'ess 
  at 
  a 
  lower 
  temperature. 
  The 
  results 
  

   are 
  recorded 
  in 
  Table 
  It. 
  They 
  fully 
  confirm 
  the 
  results 
  of 
  the 
  

   experiment 
  last 
  recorded. 
  Of 
  the 
  males, 
  Nos. 
  1, 
  2, 
  3, 
  4, 
  and 
  5, 
  all 
  

   of 
  which 
  had 
  had 
  from 
  one 
  and 
  a 
  half 
  to 
  fom* 
  days' 
  forcing, 
  

   approach 
  the 
  summer 
  colouring, 
  and 
  there 
  is 
  not 
  much 
  difference 
  

   between 
  them 
  ; 
  No, 
  6, 
  with 
  only 
  one 
  day's 
  forcmg, 
  is 
  darker. 
  

   Nos. 
  7 
  and 
  8, 
  with 
  no 
  forcing 
  at 
  all, 
  are 
  decidedly 
  darker. 
  Of 
  the 
  

   females, 
  Nos. 
  7 
  and 
  8, 
  with 
  no 
  forcing 
  at 
  all, 
  are 
  decidedly 
  darker 
  

   than 
  Nos. 
  1, 
  2, 
  3, 
  4, 
  and 
  5, 
  which 
  had 
  had 
  fi'om 
  one 
  to 
  three 
  and 
  a 
  

   half 
  days' 
  forcing. 
  

  

  The 
  last 
  class 
  of 
  experiments 
  was 
  repeated 
  with 
  pupae 
  fi'om 
  

   another 
  brood 
  not 
  of 
  the 
  " 
  red" 
  type, 
  offspring 
  of 
  a 
  brood 
  kindly 
  

   reared 
  for 
  me 
  by 
  Mr. 
  HoUis, 
  but 
  of 
  a 
  more 
  ordinary 
  and 
  variable 
  

   colour. 
  They 
  were 
  contemporaries 
  of 
  the 
  "red 
  a," 
  andfom-teen 
  of 
  

   them 
  were 
  treated 
  in 
  exactly 
  the 
  same 
  way, 
  sis 
  males 
  and 
  six 
  

   females 
  being 
  in 
  the 
  same 
  manner 
  selected 
  for 
  first 
  forcing 
  and 
  

   then 
  outdoor 
  exposure, 
  and 
  eight 
  males 
  and 
  eight 
  females 
  for 
  out- 
  

   door 
  exposure 
  first 
  and 
  then 
  forcing. 
  The 
  results 
  are 
  in 
  the 
  same 
  

   direction, 
  though 
  not 
  so 
  marked. 
  The 
  experiments 
  with 
  "red 
  

   a 
  " 
  and 
  with 
  the 
  last-named 
  brood 
  showed 
  that 
  about 
  three 
  days 
  of 
  

   a 
  temperature 
  averaging 
  56° 
  were 
  equivalent, 
  in 
  the 
  rate 
  of 
  pupal 
  

   progress, 
  to 
  one 
  day 
  at 
  80°. 
  

  

  The 
  general 
  result 
  of 
  the 
  experiments 
  on 
  the 
  three 
  last-mentioned 
  

   broods 
  may 
  be 
  stated 
  to 
  be 
  that 
  fi-om 
  two 
  to 
  three 
  days" 
  forcing 
  

   during 
  the 
  last 
  parts 
  of 
  the 
  pupal 
  stage 
  ma^-be 
  enough 
  to 
  affect 
  the 
  

   colouring, 
  and 
  in 
  many 
  cases 
  to 
  a 
  very 
  marked 
  degi'ee. 
  

  

  (/) 
  Ordinary 
  i?idoor 
  temjoerature, 
  folloived 
  by 
  low 
  tenq^eraturc. 
  

   — 
  Another 
  experiment, 
  partly 
  founded 
  on 
  an 
  accidental 
  occurrence, 
  

   shows 
  corresponding 
  results, 
  from 
  the 
  exposiu'e 
  of 
  part 
  of 
  a 
  summer 
  

   brood 
  to 
  the 
  lower 
  "cooling" 
  temperature. 
  A 
  red 
  brood 
  of 
  the 
  

   third 
  generation, 
  fed 
  up 
  rapidly, 
  and 
  rather 
  unexpectedly 
  pupated 
  

   before 
  the 
  middle 
  of 
  August. 
  They 
  were 
  brought 
  indoors, 
  where 
  

   more 
  than 
  a 
  dozen 
  were 
  found 
  to 
  have 
  emerged 
  on 
  the 
  21st 
  August 
  

   at 
  the 
  ordinary 
  temperature 
  of 
  the 
  room. 
  The 
  remainder 
  were 
  

  

  