﻿ADKINIA 
  BIPUNCTIDACTYLA. 
  887 
  

  

  variable 
  in 
  both 
  ; 
  they 
  cannot, 
  therefore, 
  have 
  specific 
  value. 
  He 
  adds 
  

   that 
  the 
  species 
  mentioned 
  by 
  Biittner 
  and 
  Hering 
  (Stett. 
  Ent. 
  Zeitg., 
  

   1880, 
  p. 
  472; 
  1891, 
  p. 
  225; 
  1893, 
  p. 
  117), 
  and 
  which 
  was 
  erroneously 
  

   referred 
  by 
  Stainton 
  to 
  plagiodactylus, 
  is 
  not 
  that 
  insect, 
  but 
  S. 
  var. 
  

   pneumonanthes, 
  Schleich. 
  He 
  then 
  writes 
  : 
  " 
  In 
  his 
  analytical 
  table 
  

   Heinernann 
  places 
  plagiodactyla 
  among 
  the 
  species 
  which 
  have 
  a 
  thick,, 
  

   dark, 
  longitudinal 
  streak 
  in 
  the 
  upper 
  segment 
  of 
  the 
  front 
  wings, 
  and 
  

   which 
  are 
  said 
  by 
  this 
  to 
  be 
  separated 
  from 
  bipunctidactyla 
  (serotina) 
  ; 
  

   this 
  character, 
  however, 
  as 
  in 
  bipunctidactyla, 
  is 
  very 
  variable. 
  Among 
  

   the 
  six 
  examples 
  above 
  mentioned, 
  it 
  is 
  absent 
  in 
  three, 
  very 
  indistinct 
  

   in 
  one, 
  and 
  only 
  distinct 
  in 
  two 
  ; 
  the 
  same 
  thing 
  happens, 
  however, 
  

   often 
  with 
  bipunctidactyla. 
  Again, 
  the 
  costal 
  fringes 
  in 
  plagiodactyla 
  

   are 
  said 
  to 
  be 
  brown, 
  narrowly 
  white 
  towards 
  the 
  apex; 
  this 
  character, 
  

   also, 
  is 
  only 
  to 
  be 
  found 
  distinctly 
  in 
  two 
  of 
  my 
  original 
  six 
  specimens, 
  

   while, 
  on 
  the 
  other 
  hand, 
  it 
  occurs 
  in 
  many 
  a 
  specimen 
  of 
  bipunctidac- 
  

   tyla. 
  The 
  position 
  of 
  the 
  dots 
  at 
  the 
  fissure 
  is 
  exactly 
  the 
  same 
  as 
  in 
  

   bipunctidactyla, 
  namely, 
  just 
  on 
  the 
  fissure, 
  never 
  somewhat 
  distant 
  

   from 
  it 
  as 
  in 
  graphodaciyla 
  and 
  coprodactyla. 
  I, 
  therefore, 
  can 
  

   only 
  consider 
  plagiodactyla 
  as 
  a 
  variety 
  of 
  bipunctidactyla, 
  which 
  

   latter, 
  according 
  to 
  Zeller 
  (Linn. 
  Ent., 
  vi., 
  p. 
  361), 
  has 
  less 
  brightly 
  

   marked 
  forewings, 
  fewer 
  white 
  scales 
  on 
  the 
  disc, 
  not 
  such 
  a 
  thick, 
  

   blackish- 
  brown, 
  streak 
  on 
  the 
  upper 
  segment, 
  which 
  is 
  also 
  a 
  little 
  

   shorter 
  than 
  in 
  plagiodactyla." 
  We 
  quite 
  agree 
  with 
  Hofmann's 
  

   conclusion. 
  Hofmann 
  also 
  notices 
  the 
  important 
  detail, 
  viz., 
  that 
  Frey 
  

   merely 
  quotes 
  Zeller's 
  diagnosis 
  of 
  plagiodactylus, 
  and 
  that 
  his 
  larval 
  

   reference 
  " 
  belongs' 
  in 
  all 
  probability 
  to 
  graphodactyla," 
  the 
  latter- 
  

   having 
  been 
  bred 
  by 
  Hofmann 
  from 
  Oentiana 
  asclepiadea. 
  This 
  

   suggestion 
  is 
  abundantly 
  proved 
  by 
  the 
  fact 
  that 
  the 
  whole 
  series 
  of 
  

   specimens 
  in 
  the 
  "Frey" 
  collection, 
  labelled 
  " 
  plagiodactylus 
  " 
  are 
  

   pneumonanthes. 
  Haphazard 
  records, 
  combined 
  with 
  ignorance 
  of 
  the 
  

   character 
  of 
  plagiodactylus 
  as 
  a 
  race, 
  have 
  led 
  to 
  many 
  more 
  or 
  less 
  

   ordinary 
  specimens 
  of 
  A. 
  bipunctidactyla 
  being 
  recorded 
  in 
  Britain 
  as- 
  

   plagiodactylus 
  and 
  scabiodactylus, 
  the 
  two 
  names 
  given 
  to 
  a 
  slightly 
  

   darker 
  and 
  more 
  strongly- 
  marked 
  form 
  than 
  the 
  type, 
  and 
  reams 
  of 
  

   paper 
  have 
  been 
  wasted, 
  in 
  the 
  British 
  magazines, 
  in 
  trying 
  to 
  prove 
  

   the 
  specific 
  distinctness 
  of 
  the 
  latter 
  form. 
  That 
  both 
  forms 
  are 
  

   specifically 
  identical, 
  there 
  can 
  be 
  no 
  question, 
  and 
  that 
  A. 
  bipunctidactyla 
  

   develops, 
  in 
  most 
  localities, 
  well-marked 
  specimens 
  of 
  the 
  plagiodactylus 
  

   form, 
  where 
  the 
  greater 
  number 
  of 
  the 
  examples 
  are 
  typical, 
  is 
  

   undoubted, 
  but 
  there 
  are 
  localities, 
  chiefly 
  those 
  of 
  higher 
  latitudes, 
  

   higher 
  altitudes, 
  and 
  more 
  exposed 
  places, 
  where 
  the 
  greater 
  number 
  

   of 
  examples 
  are 
  of 
  this 
  form, 
  and 
  where 
  it 
  has 
  developed 
  into 
  a 
  well- 
  

   marked 
  race. 
  The 
  variation 
  of 
  a 
  long 
  series 
  of 
  British 
  examples 
  

   suggests 
  the 
  following 
  subdivisions 
  : 
  — 
  

  

  1. 
  Unicolorous 
  greyish-white, 
  with 
  fissural 
  and 
  disoal 
  dots 
  — 
  ab. 
  albescens, 
  n. 
  

   ab. 
  

  

  la. 
  Unicolorous 
  pale 
  drab-grey 
  or 
  ashy, 
  soaroely 
  sprinkled 
  with 
  black, 
  or 
  with 
  

   white, 
  scales, 
  with 
  fissural 
  dots, 
  but 
  without 
  discal 
  dot 
  ab. 
  pallida, 
  n. 
  ab. 
  

  

  16. 
  Pale 
  drab-grey 
  or 
  ashy, 
  sprinkled 
  with 
  blaok, 
  and 
  with 
  white 
  scales, 
  with 
  

   fissural 
  dots, 
  but 
  without 
  discal 
  dot 
  ab. 
  pallida-mixta, 
  n. 
  ab. 
  

  

  lc. 
  As 
  l/>, 
  but 
  also 
  with 
  discal 
  dot 
  -.bipunctidactyla, 
  Scop. 
  

  

  li/. 
  As 
  Lc, 
  but 
  with 
  black 
  LineolsB 
  in 
  the 
  upper 
  or 
  Lower 
  lobes, 
  or 
  in 
  both 
  ab. 
  

   pallida-excessa, 
  n, 
  ab, 
  

  

  2. 
  Costal 
  area 
  greyish-drab, 
  or 
  darkish-grey, 
  the 
  inner 
  marginal 
  area 
  oohreous 
  

  

  01" 
  brownish, 
  scarcely 
  sprinkled 
  with 
  black, 
  or 
  with 
  white, 
  scales, 
  with 
  tissural 
  dots, 
  

   but 
  without 
  discal 
  dot 
  — 
  ab. 
  bicolor, 
  n. 
  ab. 
  

  

  