﻿44 
  

  

  BKITISH 
  LEPIDOPTERA. 
  

  

  should 
  be 
  in 
  the 
  proportion 
  of 
  1DD,2DB, 
  1ER, 
  the 
  form 
  DD 
  representing 
  

   an 
  insect 
  derived 
  from 
  an 
  ovum 
  and 
  spermatozoon 
  each 
  bearing 
  the 
  

   dominant 
  character, 
  BR 
  from 
  two 
  germ 
  -cells 
  bearing 
  the 
  recessive 
  

   character, 
  and 
  DR 
  from 
  germ- 
  cells, 
  one 
  of 
  which 
  bore 
  the 
  dominant, 
  

   the 
  other 
  the 
  recessive, 
  but, 
  in 
  every 
  case 
  where 
  a 
  dominant- 
  bearing 
  

   germ-cell 
  has 
  taken 
  part 
  in 
  fertilisation, 
  the 
  offspring 
  will 
  show 
  the 
  

   dominant 
  character, 
  so 
  that, 
  in 
  the 
  second 
  generation 
  from 
  the 
  cross, 
  

   one 
  quarter 
  only 
  of 
  the 
  insects 
  should 
  appear 
  with 
  the 
  recessive 
  (flavo- 
  

   fasciata) 
  character. 
  Of 
  the 
  remaining 
  three-quarters, 
  all 
  of 
  which 
  

   will 
  be 
  gross 
  ulariata, 
  two 
  -thirds 
  will 
  be 
  hybrid 
  in 
  nature, 
  and 
  will 
  give 
  

   recessive 
  Jiavofasciata 
  when 
  bred 
  together, 
  while 
  the 
  remainder 
  will 
  be 
  

   pure 
  grossulariata, 
  and 
  will 
  never 
  throw 
  Jiavofasciata 
  when 
  bred 
  

   together. 
  This 
  particular 
  instance 
  is 
  complicated 
  by 
  the 
  fact 
  that 
  

   flavofasciata 
  is 
  confined 
  to 
  the 
  female, 
  and, 
  therefore, 
  if 
  a 
  specimen 
  is 
  

   paired 
  with 
  a 
  pure 
  grossulariata, 
  no 
  flavofasciata 
  will 
  appear 
  in 
  the 
  

   offspring 
  ; 
  but 
  it 
  should 
  be 
  possible 
  to 
  breed 
  flavofasciata 
  in 
  every 
  

   generation 
  by 
  pairing 
  it 
  with 
  a 
  dominant 
  hybrid 
  (DR) 
  which 
  has 
  the 
  

   grossulariata 
  character 
  in 
  appearance, 
  but 
  also 
  the 
  recessive 
  flavo- 
  

   fasciata 
  character 
  in 
  a 
  latent 
  condition. 
  Mr. 
  Raynor 
  does 
  not 
  tell 
  us 
  

   what 
  proportion 
  of 
  his 
  insects 
  were 
  flavofasciata 
  in 
  the 
  second 
  

   generation 
  from 
  the 
  cross, 
  but 
  this 
  is 
  a 
  matter 
  of 
  considerable 
  interest, 
  

   for 
  if 
  there 
  were 
  much 
  less 
  than 
  a 
  quarter 
  of 
  the 
  whole, 
  which 
  the 
  

   Mendelian 
  theory 
  leads 
  us 
  to 
  expect, 
  it 
  might 
  indicate 
  that 
  there 
  is 
  

   a 
  male 
  flavofasciata 
  which 
  has 
  the 
  character 
  of 
  grossulariata, 
  and, 
  

   therefore, 
  cannot 
  be 
  distinguished 
  from 
  it 
  except 
  by 
  breeding 
  it 
  with 
  

   a 
  flavofasciata 
  $ 
  , 
  in 
  which 
  case 
  all 
  the 
  females 
  produced 
  from 
  such 
  

   an 
  union 
  should 
  be 
  flavofasciata. 
  Not 
  all 
  Mendelian 
  cases 
  are 
  so 
  

   simple, 
  for 
  there 
  may 
  be 
  two 
  or 
  more 
  characters 
  which 
  are 
  inherited 
  

   separately, 
  but 
  it 
  seems 
  worth 
  while 
  to 
  call 
  the 
  attention 
  of 
  entomo- 
  

   logists 
  to 
  the 
  matter, 
  for 
  most 
  of 
  the 
  work 
  upon 
  the 
  Mendelian 
  theory 
  

   has 
  been 
  done 
  upon 
  vertebrate 
  animals 
  and 
  flowering 
  plants, 
  and 
  it 
  

   would 
  be 
  of 
  great 
  value 
  to 
  have 
  additional 
  evidence 
  from 
  insects. 
  

   Further 
  details 
  relating 
  to 
  this 
  subject 
  are 
  noted 
  (postea 
  p. 
  65), 
  Raynor 
  

   having 
  since 
  bred 
  $ 
  s 
  of 
  the 
  flavofasciata 
  form. 
  

  

  In 
  dealing 
  with 
  the 
  details 
  we 
  have 
  been 
  able 
  to 
  collect, 
  relating 
  to 
  

   the 
  question 
  of 
  mongrelisation, 
  we 
  think 
  it 
  may 
  be 
  well 
  to 
  consider 
  

   them 
  under 
  the 
  following 
  headings. 
  

  

  I. 
  Crossing 
  of 
  typical 
  form 
  and 
  local 
  race. 
  

  

  Standfuss 
  is 
  one 
  of 
  the 
  few 
  authors 
  who 
  has 
  worked 
  out 
  mon- 
  

   grelisation 
  experiments 
  on 
  the 
  basis 
  of 
  obtaining 
  data 
  similar 
  to 
  those 
  

   obtained 
  by 
  hybridisation 
  experiments, 
  and 
  Dixey 
  [Science 
  Progress, 
  

   vii., 
  April, 
  1898) 
  considers 
  the 
  results 
  in 
  many 
  cases 
  analogous. 
  The 
  

   facts 
  at 
  our 
  disposal 
  concerning 
  the 
  crossing 
  of 
  a 
  type 
  form 
  with 
  a 
  

   local 
  race 
  may 
  be 
  summarised 
  as 
  follows 
  : 
  — 
  

  

  1. 
  Callimorpha 
  dominula 
  $ 
  x 
  persona 
  ? 
  . 
  — 
  In 
  these 
  crossings, 
  the 
  

   imaginal 
  issue 
  produced, 
  though 
  very 
  variable, 
  resembled 
  on 
  the 
  whole 
  

   dominula 
  rather 
  tban 
  persona. 
  In 
  one 
  brood, 
  however, 
  a 
  majority 
  

   more 
  closely 
  resembled 
  the 
  latter, 
  whilst 
  one 
  specimen 
  was 
  even 
  more 
  

   extreme 
  than 
  ordinary 
  persona. 
  From 
  3 
  to 
  5 
  per 
  cent, 
  of 
  the 
  eggs 
  

   were 
  sterile 
  (Handbuch, 
  etc., 
  pp. 
  220-221, 
  pi. 
  v., 
  figs. 
  6-10). 
  Of 
  the 
  

   five 
  examples 
  figured 
  from 
  this 
  crossing, 
  three 
  are 
  noted 
  by 
  Standfuss 
  

   as 
  C. 
  ab. 
  romanovi, 
  Stdfss. 
  (with 
  red 
  hindwings 
  and 
  excess 
  of 
  black 
  

   markings), 
  one 
  is 
  a 
  C. 
  ab. 
  italica 
  (with 
  yellow 
  hindwings 
  and 
  excess 
  

  

  