﻿the 
  markitigs 
  and 
  colouring 
  of 
  Lejmloptera. 
  161 
  

  

  then 
  placed 
  in 
  the 
  refrigerator, 
  where 
  by 
  the 
  6th 
  September 
  twenty 
  

   more 
  had 
  emerged. 
  All 
  are 
  slightly 
  darker 
  than 
  their 
  forced 
  red 
  

   parents 
  of 
  the 
  second 
  generation, 
  but 
  such 
  as 
  emerged 
  after 
  the 
  

   15th 
  September, 
  i. 
  e., 
  after 
  twenty-six 
  days 
  of 
  the 
  low 
  temperature, 
  

   are 
  decidedly 
  darker 
  than 
  the 
  others. 
  A 
  light 
  uncooled 
  male 
  and 
  

   another 
  cooled 
  are 
  given 
  as 
  Figs. 
  1 
  and 
  2 
  in 
  the 
  Plate. 
  

  

  The 
  conclusions 
  to 
  be 
  drawn 
  from 
  this 
  experiment 
  seem 
  to 
  be 
  (1) 
  

   that 
  keeping 
  the 
  pupae 
  at 
  the 
  ordinary 
  room 
  temperature, 
  probably 
  

   about 
  65° 
  to 
  70°, 
  made 
  the 
  moths 
  slightly 
  darker 
  than 
  their 
  parents, 
  

   which 
  were 
  forced 
  ; 
  (2) 
  that 
  at 
  the 
  low 
  temperature 
  of 
  the 
  refri- 
  

   gerator, 
  averaging 
  at 
  this 
  time, 
  I 
  should 
  think, 
  about 
  43°, 
  three 
  or 
  

   four 
  weeks 
  did 
  not 
  represent, 
  in 
  pupal 
  progress 
  of 
  development, 
  

   more 
  than 
  two 
  or 
  three 
  days 
  of 
  a 
  forcing 
  temperature, 
  the 
  lower 
  

   temperature, 
  as 
  in 
  the 
  other 
  cases, 
  producing 
  a 
  darkness 
  of 
  

   colouring. 
  

  

  In 
  connection 
  with 
  the- 
  effect 
  produced 
  by 
  moderate 
  differences 
  

   of 
  temperature, 
  I 
  may 
  here 
  mention 
  that 
  in 
  two 
  broods 
  oi 
  illustraria 
  

   pupge, 
  kindly 
  brought 
  up 
  for 
  me 
  by 
  Mr. 
  Weldon 
  at 
  Plymouth, 
  and 
  

   kept 
  indoors, 
  some 
  that 
  emerged 
  within 
  a 
  day 
  or 
  two 
  of 
  their 
  

   arrival 
  in 
  June 
  and 
  July 
  are 
  conspicuously 
  darker 
  in 
  colouring 
  than 
  

   the 
  rest 
  of 
  the 
  broods 
  which 
  were 
  forced. 
  I 
  should 
  think 
  it 
  impro- 
  

   bable 
  that 
  the 
  vinforced 
  ones 
  had 
  been 
  at 
  a 
  lower 
  average 
  tempera- 
  

   ture 
  than 
  60°. 
  

  

  EXPEEIMENTS 
  ON 
  E. 
  AUTUMNARIA. 
  

  

  The 
  other 
  systematic 
  experiments 
  tried 
  were 
  with^. 
  autumnaria. 
  

   Dr. 
  Chapman 
  kindly 
  sent 
  me 
  two 
  large 
  batches 
  of 
  eggs, 
  the 
  moths 
  

   from 
  which 
  I 
  found, 
  after 
  a 
  few 
  had 
  been 
  forced, 
  were 
  very 
  

   similar; 
  and 
  after 
  a 
  time 
  I 
  mixed 
  the 
  larvae. 
  

  

  (g) 
  Forcing 
  all 
  through, 
  or 
  brief 
  cooling 
  followed 
  hy 
  forcing. 
  — 
  

   Some 
  were 
  forced 
  all 
  through 
  as 
  pupae 
  ; 
  others 
  were 
  cooled 
  for 
  

   3, 
  7, 
  10, 
  14, 
  17, 
  and 
  21 
  days, 
  then 
  forced, 
  emerging 
  in 
  from 
  

   10 
  to 
  15 
  days 
  of 
  the 
  forcing 
  temperature. 
  Thirty 
  moths 
  emerged 
  

   (rejecting 
  cripples). 
  There 
  are 
  considerable 
  individual 
  differences 
  

   among 
  these, 
  but 
  the 
  only 
  great 
  difference 
  of 
  a 
  general 
  character 
  

   is 
  that 
  after 
  about 
  14 
  or 
  17 
  days' 
  cooling 
  the 
  colouring 
  and 
  

   markings 
  are 
  less 
  vivid, 
  the 
  ground 
  colour 
  is 
  dulled, 
  the 
  spotting 
  

   blurred, 
  the 
  outer 
  line 
  broadened, 
  and 
  the 
  inner 
  line 
  shows 
  a 
  

   tendency 
  to 
  disappear. 
  

  

  (h) 
  Cooling, 
  followed 
  by 
  an 
  ordinary 
  indoor 
  temperature, 
  — 
  

   Others, 
  after 
  being 
  cooled 
  for 
  7, 
  10, 
  14, 
  17, 
  21, 
  and 
  28 
  days 
  were 
  

   then, 
  instead 
  of 
  being 
  forced, 
  kept 
  at 
  the 
  ordinary 
  temperature 
  of 
  

   the 
  room, 
  averaging, 
  I 
  think, 
  about 
  65° 
  to 
  70° 
  in 
  July, 
  till 
  they 
  

   emerged, 
  which 
  they 
  did, 
  to 
  the 
  number 
  of 
  20 
  (rejecting 
  cripples), 
  

   in 
  from 
  13 
  to 
  21 
  days. 
  These, 
  also 
  showing 
  considerable 
  individual 
  

  

  TliANS. 
  ENT. 
  SOC. 
  LOND, 
  1891, 
  — 
  PART 
  I. 
  (MARCH.) 
  M 
  

  

  