﻿HYBRIDISATION 
  IN 
  LEPIDOPTERA. 
  11 
  

  

  writes 
  : 
  " 
  The 
  fact 
  that, 
  in 
  the 
  experiments 
  undertaken, 
  the 
  male 
  

   Closterid 
  hybrids 
  develop 
  much 
  more 
  quickly 
  than 
  their 
  sister 
  females, 
  

   and 
  that 
  the 
  male 
  hybrid 
  immediately 
  produces 
  (when 
  crossed 
  with 
  a 
  

   pure 
  2 
  ) 
  a 
  large 
  third 
  generation 
  of 
  males, 
  indicates 
  a 
  progressive 
  develop- 
  

   mental 
  tendency, 
  which 
  is 
  further 
  confirmed 
  by 
  other 
  facts. 
  

   On 
  the 
  other 
  hand, 
  with 
  regard 
  to 
  the 
  2 
  s 
  of 
  the 
  Closterid 
  hybrids, 
  

   they 
  endeavour 
  to 
  return 
  to 
  the 
  original 
  simple 
  state 
  of 
  one 
  brood 
  per 
  

   year 
  (for 
  this 
  was 
  certainly 
  the 
  primitive 
  condition)." 
  As 
  bearing 
  on 
  

   the 
  point 
  now 
  under 
  review, 
  i.e., 
  the 
  different 
  action 
  of 
  hybridism 
  on 
  

   the 
  two 
  sexes 
  of 
  the 
  resultant 
  progeny, 
  so 
  far 
  as 
  relates 
  to 
  the 
  length 
  

   of 
  the 
  early 
  stages, 
  we 
  may 
  note 
  that, 
  when 
  Standfuss 
  bred 
  Drepana 
  

   hybr. 
  rebeli, 
  the 
  $ 
  and 
  2 
  hybrids 
  emerged 
  together, 
  whilst 
  with 
  the 
  

   reciprocal 
  cross, 
  D. 
  hybr. 
  ziirichi, 
  the 
  $ 
  s 
  developed 
  at 
  once, 
  and 
  

   produced 
  imagines, 
  whilst 
  the 
  females 
  hybernated 
  as 
  pupae. 
  This 
  

   difference 
  was 
  already 
  foreshadowed 
  during 
  pupation, 
  for, 
  whilst 
  the 
  $ 
  

   larvae 
  only 
  bent 
  round 
  a 
  small 
  portion 
  of 
  the 
  edge 
  of 
  the 
  leaf, 
  and 
  fixed 
  

   themselves 
  in 
  the 
  same 
  by 
  a 
  few 
  short 
  threads 
  on 
  the 
  surface, 
  and 
  changed 
  

   to 
  pupae 
  in 
  the 
  more 
  or 
  less 
  open 
  pockets 
  thus 
  formed, 
  those 
  of 
  the 
  2 
  s, 
  

   on 
  the 
  other 
  hand, 
  rolled 
  a 
  large 
  portion 
  of 
  the 
  leaf 
  sharply 
  round, 
  begin- 
  

   ning 
  at 
  the 
  edge, 
  and 
  closed 
  over 
  the 
  so-formed 
  pocket 
  with 
  

   numerous 
  strong 
  silk 
  threads, 
  with 
  the 
  exception 
  of 
  a 
  small 
  

   opening 
  to 
  allow 
  the 
  larva 
  egress, 
  and 
  then 
  gnawed 
  this 
  puparium 
  

   loose 
  from 
  the 
  rest 
  of 
  the 
  leaf, 
  so 
  that 
  it 
  fell 
  into 
  the 
  sleeve, 
  and 
  then 
  

   fastened 
  up 
  the 
  opening. 
  In 
  this 
  manner, 
  the 
  pupa 
  was 
  better 
  pro- 
  

   tected 
  against 
  many 
  dangers 
  than 
  if 
  it 
  fell, 
  in 
  late 
  autumn, 
  with 
  the 
  

   rest 
  of 
  the 
  leaves. 
  Standfuss 
  further 
  notes 
  (Entom., 
  xxxiv., 
  p. 
  78) 
  

   that 
  the 
  $ 
  larvae 
  of 
  Clostera 
  hybr. 
  prima 
  developed 
  much 
  more 
  rapidly 
  

   than 
  the 
  2 
  larvae, 
  so 
  much 
  so 
  that 
  he 
  would 
  have 
  got 
  no 
  pairings 
  had 
  

   he 
  not 
  artificially 
  exposed 
  the 
  $ 
  imagines 
  to 
  a 
  low 
  temperature, 
  and 
  

   so 
  kept 
  them 
  in 
  a 
  torpid 
  state 
  for 
  some 
  weeks, 
  until 
  the 
  2 
  s 
  emerged. 
  

   A 
  parallel 
  fact 
  was 
  noted 
  with 
  regard 
  to 
  C. 
  hybr. 
  inversa, 
  although 
  the 
  

   interval 
  of 
  time 
  between 
  the 
  emergence 
  of 
  the 
  $ 
  s 
  and 
  2 
  s 
  was 
  much 
  

   less. 
  Strangely 
  enough, 
  Newman 
  records 
  an 
  exactly 
  opposite 
  result 
  

   (Proc. 
  Sth. 
  Lond. 
  Ent. 
  Soc, 
  1899, 
  p. 
  110) 
  for 
  a 
  large 
  brood 
  of 
  larvae 
  of 
  

   Clostera 
  hybr. 
  prima, 
  which 
  fed 
  up 
  rapidly, 
  and 
  of 
  which 
  about 
  240 
  pupa- 
  

   ted, 
  one-half 
  — 
  117 
  2 
  s 
  and 
  3 
  $ 
  s 
  — 
  emerging 
  at 
  the 
  end 
  of 
  August, 
  the 
  

   quickest 
  being 
  only 
  32 
  days 
  from 
  the 
  hatching 
  of 
  egg 
  to 
  imago, 
  the 
  

   rest 
  of 
  the 
  pupae 
  going 
  over 
  the 
  winter, 
  the 
  imagines 
  emerging 
  the 
  next 
  

   spring. 
  Bacot's 
  experiments 
  (1900-1902) 
  in 
  breeding 
  Malacosoma 
  

   hybr. 
  schaufussi 
  gave 
  a 
  similar 
  result 
  to 
  that 
  of 
  Newman, 
  for 
  he 
  

   records 
  (Proc. 
  Ent. 
  Soc. 
  Lond., 
  1902, 
  p. 
  vii) 
  that 
  his 
  last 
  females 
  

   emerged 
  in 
  1901, 
  a 
  good 
  three 
  weeks 
  before 
  the 
  earliest 
  male, 
  and 
  thus 
  

   prevented 
  pairings 
  between 
  the 
  hybrids, 
  the 
  female 
  larvse 
  having 
  fed 
  

   up 
  at 
  an 
  unprecedentedly 
  rapid 
  rate, 
  and 
  emerging 
  not 
  only 
  earlier 
  than 
  

   the 
  $ 
  hybrids, 
  but 
  much 
  sooner 
  than 
  either 
  sex 
  of 
  the 
  parent 
  forms. 
  

   In 
  1902, 
  another 
  experiment 
  (op.cit., 
  p. 
  xxv) 
  based 
  on 
  the 
  same 
  species, 
  

   produced 
  an 
  almost 
  exactly 
  similar 
  result. 
  On 
  the 
  other 
  hand, 
  the 
  

   larvae 
  of 
  Amphidasys 
  hybr. 
  herefordi 
  (Ent. 
  /iVc, 
  ii., 
  p. 
  88) 
  showed 
  groat 
  

   variation 
  in 
  the 
  rate 
  of 
  feeding 
  up, 
  and 
  in 
  the 
  length 
  of 
  the 
  pupal 
  

   stage. 
  Some 
  half-dozen 
  of 
  these 
  Larvse 
  missed 
  a 
  moult, 
  pupated 
  early. 
  

   and 
  produced 
  imagines 
  the 
  same 
  autumn, 
  whilst 
  the 
  rest 
  developed 
  

   into 
  pupse 
  which 
  went 
  over 
  the 
  winter, 
  one 
  attempting 
  to 
  go 
  over 
  a 
  

   second 
  winter. 
  So 
  marked 
  was 
  the 
  result 
  of 
  the 
  hybridisation 
  on 
  the 
  

  

  