﻿HYBRIDISATION 
  IN 
  LEPIDOPTERA. 
  33 
  

  

  One 
  batch 
  of 
  eggs, 
  hatched 
  April 
  6th 
  ; 
  some 
  larvae 
  fullfed 
  by 
  May 
  9th 
  ; 
  larvae 
  

   mostly 
  like 
  that 
  of 
  the 
  ? 
  parent 
  (bistortata) 
  , 
  only 
  a 
  few 
  having 
  the 
  apex 
  of 
  the 
  /^- 
  

   mark 
  open 
  like 
  the 
  larva 
  of 
  T. 
  crepuscularia. 
  Most 
  of 
  the 
  larvae 
  pupated 
  about 
  the 
  

   middle 
  of 
  May. 
  Imagines 
  commenced 
  to 
  emerge 
  early 
  in 
  June, 
  at 
  first 
  rapidly 
  

   and 
  afterwards 
  more 
  slowly, 
  until 
  end 
  of 
  June 
  ; 
  there 
  was 
  then 
  a 
  break 
  until 
  July 
  

   16th, 
  when 
  they 
  again 
  commenced 
  to 
  emerge, 
  and 
  continued 
  to 
  do 
  so 
  at 
  intervals 
  

   until 
  the 
  first 
  week 
  in 
  September 
  ; 
  one 
  specimen 
  emerged 
  during 
  the 
  last 
  week 
  in 
  

   October. 
  58 
  specimens 
  emerged, 
  all 
  males 
  — 
  29 
  pale 
  and 
  29 
  dark 
  specimens 
  = 
  T. 
  

   hybr. 
  bacoti-suffusa, 
  n. 
  hybr. 
  

  

  iii. 
  Hybrid 
  between 
  j 
  T. 
  bistortata 
  x 
  ? 
  T. 
  crepuscularia. 
  — 
  Of 
  this 
  cross 
  there 
  

   were 
  two 
  different 
  broods. 
  Of 
  the 
  first, 
  (a) 
  (marked 
  3a 
  in 
  Bacot's 
  pairings), 
  the 
  

   larvae 
  for 
  the 
  most 
  part 
  followed 
  the 
  & 
  parent 
  (bistortata), 
  only 
  a 
  few 
  having 
  the 
  

   apex 
  of 
  the 
  y^-mark 
  open 
  as 
  in 
  that 
  of 
  ? 
  parent 
  ; 
  fullfed 
  from 
  about 
  16th 
  to 
  

   20th 
  May. 
  22 
  specimens 
  emerged 
  — 
  14 
  c? 
  sand 
  8 
  ? 
  s. 
  These 
  emerged 
  in 
  June, 
  with 
  

   the 
  exception 
  of 
  two 
  (which 
  came 
  out 
  in 
  July). 
  (/3) 
  Of 
  the 
  other 
  brood 
  of 
  this 
  cross 
  

   (marked 
  3/3) 
  a 
  fair 
  number 
  of 
  the 
  larvae 
  fed 
  up 
  and 
  pupated 
  very 
  quickly, 
  but 
  others 
  

   fed 
  up 
  slowly, 
  and 
  did 
  not 
  go 
  down 
  until 
  the 
  earliest 
  specimens 
  had 
  commenced 
  to 
  

   emerge; 
  larvae 
  unhealthy, 
  large 
  proportion 
  died. 
  9 
  specimens 
  emerged 
  — 
  six 
  males 
  

   and 
  3 
  females. 
  Four 
  minute 
  specimens 
  — 
  Jfin. 
  (s), 
  £fhi. 
  (2 
  ? 
  s), 
  ljin. 
  (1 
  ? 
  ). 
  

   These 
  small 
  specimens 
  emerged 
  in 
  late 
  June, 
  two 
  normal 
  specimens 
  in 
  early 
  June, 
  

   one 
  on 
  September 
  29th, 
  and 
  two 
  late 
  in 
  October. 
  It 
  may 
  be 
  well 
  to 
  mention 
  here 
  

   that 
  these 
  tiny 
  specimens 
  are 
  not 
  infrequent 
  in 
  inbred 
  T. 
  bistortata. 
  Such 
  a 
  brood 
  

   as 
  this 
  last 
  is 
  practically 
  useless 
  for 
  comparative 
  purposes 
  = 
  T. 
  hybr. 
  kedingi, 
  n. 
  

   hybr. 
  

  

  Inbred 
  hybrids 
  of 
  T. 
  hybr. 
  ridingi 
  and 
  T. 
  ridingi- 
  suffusa. 
  — 
  

   T. 
  hybr. 
  ridingi 
  and 
  T. 
  hybr. 
  ridingi 
  -suffusa 
  were 
  the 
  only 
  two 
  

   hybrids 
  that 
  were 
  inbred 
  to 
  the 
  imaginal 
  stage. 
  (1) 
  Of 
  the 
  form 
  

   (ridingi) 
  both 
  Riding 
  and 
  Bacot 
  obtained 
  fertile 
  ova 
  and 
  bred 
  imagines 
  

   in 
  due 
  course. 
  The 
  former 
  obtained 
  two 
  batches 
  of 
  eggs: 
  — 
  (a) 
  Paired 
  

   August 
  10th 
  ; 
  ova 
  laid 
  August 
  12th 
  ; 
  hatched 
  during 
  the 
  fourth 
  week 
  

   of 
  August, 
  some 
  only 
  fertile. 
  (/8) 
  Paired 
  August 
  13th; 
  ova 
  laid 
  August 
  

   15th 
  ; 
  hatched 
  first 
  week 
  in 
  September. 
  By 
  October 
  22nd 
  all 
  except 
  

   thirteen 
  larvae 
  had 
  pupated. 
  The 
  first 
  two 
  imagines 
  emerged 
  on 
  

   November 
  4th, 
  five 
  fullfed 
  larvae 
  at 
  that 
  date 
  not 
  having 
  gone 
  down. 
  

   The 
  imagines 
  continued 
  to 
  emerge 
  till 
  January 
  19th, 
  1898 
  — 
  34 
  

   imagines 
  in 
  all 
  (23^ 
  s 
  and 
  11 
  2 
  s). 
  These 
  are 
  paler 
  than 
  the 
  parents, 
  

   varying 
  from 
  pale 
  brownish 
  to 
  brownish 
  -grey, 
  some 
  approaching 
  the 
  

   2nd 
  brood 
  of 
  T. 
  bistortata, 
  others 
  the 
  $ 
  s 
  of 
  T. 
  crepuscularia, 
  but 
  most 
  

   have 
  very 
  mixed 
  characters. 
  Six 
  of 
  these 
  were 
  paired 
  in 
  November, 
  

   of 
  which 
  about 
  half 
  the 
  eggs 
  hatched 
  in 
  January, 
  but 
  the 
  larvae 
  soon 
  

   died 
  (Ent. 
  Rec, 
  xi., 
  p. 
  144). 
  Bacot 
  obtained 
  two 
  similar 
  crossings, 
  

   both 
  from 
  parents 
  belonging 
  to 
  his 
  batch 
  iiia, 
  the 
  parents 
  being 
  in 
  

   each 
  case 
  normal 
  for 
  that 
  brood 
  — 
  (a) 
  Pairing 
  took 
  place 
  on 
  June 
  17th, 
  

   1897 
  ; 
  22 
  imagines 
  emerged, 
  12 
  £ 
  s 
  and 
  10 
  $ 
  s, 
  between 
  the 
  middle 
  of 
  

   August 
  and 
  end 
  of 
  October, 
  (p) 
  Of 
  this 
  brood, 
  8 
  imagines, 
  4^ 
  s 
  and 
  4 
  

   $ 
  s, 
  emerged 
  during 
  August, 
  and 
  others 
  continued 
  to 
  do 
  so 
  until 
  the 
  end 
  

   of 
  October. 
  (2) 
  Of 
  the 
  latter 
  (Hdingi-suffusa), 
  the 
  parents 
  were 
  both 
  taken 
  

   from 
  Bacot's 
  batch 
  i. 
  They 
  paired 
  on 
  June 
  13th, 
  and 
  as 
  progeny 
  

   produced, 
  in 
  September, 
  only 
  two 
  small 
  round-winged 
  imagines 
  — 
  one 
  a 
  

   S 
  (l-|in. 
  in 
  expanse) 
  suffused 
  with 
  ochreous-fuscous, 
  and 
  with 
  distinct 
  

   transverse 
  lines; 
  the 
  other 
  a 
  ? 
  (ljins. 
  in 
  expanse), 
  whitish 
  ground 
  

   colour, 
  with 
  basal 
  and 
  median 
  bands, 
  and 
  well-developed 
  submarginal 
  

   lines 
  to 
  forewings, 
  and 
  median 
  and 
  outer 
  bands 
  to 
  hindwings. 
  Both 
  

   specimens 
  show 
  traces 
  of 
  a 
  fine 
  black 
  longitudinal 
  line 
  on 
  median 
  norvuro 
  

   at 
  outer 
  point 
  of 
  discoidal 
  cell, 
  and 
  a 
  small 
  black 
  costal 
  blotch 
  at 
  upper 
  

   end 
  of 
  the 
  basal 
  line. 
  This 
  latter 
  is 
  most 
  marked 
  in 
  two 
  males 
  o( 
  /'. 
  

   crepuscularia 
  (2nd 
  brood) 
  bred 
  by 
  Bacot. 
  

  

  