﻿DARWIN'S 
  KOKLASS 
  PHEASANT 
  43 
  

  

  rather 
  linear 
  in 
  its 
  extent 
  in 
  a 
  few 
  individuals, 
  though 
  so 
  faint 
  and 
  broken 
  that 
  one 
  never 
  

   thinks 
  of 
  it 
  as 
  aught 
  but 
  indefinite 
  mottling. 
  In 
  darwini 
  we 
  have 
  a 
  crystallizing 
  of 
  this 
  

   mottling, 
  and 
  in 
  well-marked 
  males 
  we 
  find, 
  especially 
  on 
  the 
  mantle, 
  four 
  very 
  distinct 
  

   longitudinal 
  black 
  lines 
  on 
  a 
  more 
  or 
  less 
  clear 
  grey 
  background. 
  On 
  almost 
  all 
  the 
  

   dorsal 
  plumage 
  this 
  advance 
  step 
  in 
  pattern 
  complexity 
  is 
  evident, 
  and 
  clearly 
  sets 
  apart 
  

   the 
  birds 
  as 
  a 
  distinct 
  species. 
  A 
  glance 
  at 
  darwini 
  shows 
  the 
  dorsal 
  plumage 
  to 
  be 
  

   doubly 
  complex 
  over 
  that 
  of 
  xanthospila, 
  just 
  as 
  the 
  latter 
  in 
  turn 
  doubles 
  that 
  of 
  

   macrolopha. 
  

  

  The 
  upper 
  tail-coverts 
  are 
  much 
  as 
  in 
  xanthospila, 
  but 
  as 
  for 
  the 
  lateral 
  rectrices, 
  

   while 
  the 
  black 
  border 
  around 
  the 
  central 
  grey 
  has 
  increased, 
  the 
  oblique 
  cross-bar 
  has 
  

   disappeared, 
  leaving 
  either 
  a 
  faint 
  spot, 
  a 
  short 
  shaft 
  line 
  or 
  no 
  trace 
  at 
  all. 
  The 
  black 
  

   on 
  the 
  under 
  tail-coverts 
  has 
  usurped 
  almost 
  all 
  the 
  basal 
  part 
  of 
  the 
  feathers, 
  while 
  the 
  

   white 
  terminal 
  portion 
  has 
  also 
  increased. 
  The 
  chestnut 
  is 
  reduced 
  to 
  a 
  small 
  lateral 
  

   spot 
  on 
  each 
  web. 
  

  

  On 
  the 
  ventral 
  surface 
  we 
  find 
  a 
  most 
  interesting 
  condition 
  of 
  affairs. 
  We 
  see 
  

   represented 
  the 
  phenomenon 
  of 
  correlated 
  concentration 
  and 
  diffusion. 
  The 
  chestnut 
  

   mid-zone 
  is 
  in 
  all 
  conditions 
  and 
  states 
  of 
  degeneration, 
  and 
  even 
  where 
  most 
  abundant 
  

   and 
  pure, 
  the 
  entire 
  under 
  plumage 
  is 
  tinged 
  strongly 
  with 
  the 
  buff 
  which 
  hints 
  of 
  the 
  

   dissolving 
  of 
  the 
  chestnut. 
  There 
  is 
  no 
  trace 
  of 
  white 
  or 
  even 
  grey, 
  except 
  on 
  the 
  sides 
  

   of 
  the 
  upper 
  breast. 
  This 
  variation 
  in 
  the 
  chestnut 
  of 
  the 
  lower 
  plumage 
  is 
  individual 
  

   and 
  wholly 
  independent 
  of 
  age. 
  

  

  In 
  the 
  most 
  strongly 
  marked 
  birds 
  the 
  chestnut 
  zone 
  would 
  be 
  called 
  merely 
  a 
  

   broad 
  line, 
  while 
  we 
  often 
  find 
  an 
  individual 
  with 
  only 
  faint 
  traces 
  on 
  a 
  few 
  feathers, 
  or 
  

   with 
  the 
  line 
  irregularly 
  broken 
  through 
  below 
  the 
  breast. 
  

  

  The 
  extreme 
  is 
  seen 
  in 
  a 
  fully 
  adult 
  individual, 
  typically 
  darwini 
  in 
  every 
  other 
  

   way, 
  in 
  which 
  the 
  chestnut 
  is 
  wholly 
  absent 
  on 
  the 
  fore 
  neck, 
  breast 
  and 
  belly. 
  

  

  Iris 
  dark 
  hazel 
  ; 
  mandibles 
  black 
  ; 
  legs 
  and 
  feet 
  blackish 
  grey. 
  Bill 
  from 
  nostril, 
  

   16 
  mm. 
  ; 
  length, 
  600; 
  wing, 
  234; 
  tail, 
  236; 
  tarsus, 
  72 
  ; 
  middle 
  toe 
  and 
  claw, 
  61 
  ; 
  spur, 
  

   about 
  15. 
  

  

  Adult 
  Female. 
  — 
  The 
  variation 
  among 
  the 
  females 
  is 
  very 
  considerable, 
  relatively 
  

   fully 
  as 
  great, 
  although 
  within 
  much 
  more 
  narrow 
  limits 
  than 
  in 
  the 
  males. 
  We 
  find 
  

   ■ 
  birds 
  which 
  are 
  warmly 
  suffused 
  with 
  rich 
  rufous 
  over 
  the 
  entire 
  under 
  surface, 
  and 
  

   again 
  through 
  a 
  series 
  of 
  gradations 
  we 
  pass 
  to 
  specimens 
  which 
  might 
  well 
  represent 
  

   the 
  colour 
  mates 
  of 
  the 
  extreme 
  styani 
  type, 
  of 
  a 
  colder 
  buff 
  below 
  than 
  any 
  other 
  

   specimen 
  of 
  xanthospila 
  or 
  macrolopha. 
  

  

  The 
  two 
  lateral 
  lines 
  of 
  black 
  throat 
  markings 
  appear 
  on 
  the 
  whole 
  to 
  be 
  denser 
  and 
  

   of 
  greater 
  extent 
  than 
  in 
  any 
  other 
  female 
  Pucrasia, 
  but 
  it 
  is 
  on 
  the 
  lateral 
  rectrices 
  that 
  

   the 
  single 
  important 
  diagnostic 
  character 
  is 
  to 
  be 
  found. 
  As 
  in 
  the 
  male, 
  the 
  distinction 
  

   from 
  xanthospila 
  lies 
  in 
  the 
  absence 
  of 
  the 
  oblique 
  black 
  cross-bar, 
  the 
  grey 
  area 
  being 
  

   entire 
  except 
  for 
  the 
  shaft-spot 
  or 
  short 
  streak 
  which 
  is 
  all 
  that 
  remains 
  of 
  the 
  bar 
  of 
  

   xanthospila. 
  

  

  Bill 
  blackish 
  brown 
  ; 
  iris 
  hazel 
  ; 
  legs 
  and 
  feet 
  leaden 
  grey. 
  Bill 
  from 
  nostril, 
  16 
  ; 
  

   length, 
  490; 
  wing, 
  200; 
  tail, 
  155; 
  tarsus, 
  66; 
  middle 
  toe 
  and 
  claw, 
  56. 
  Spur 
  usually 
  

   a 
  flat 
  scale, 
  occasionally 
  a 
  diminutive 
  spur 
  3 
  mm. 
  or 
  more 
  in 
  length. 
  

  

  