﻿198 
  Mr. 
  G. 
  T. 
  Baker's 
  notes 
  07i 
  

  

  paper, 
  though 
  of 
  equal 
  accessibility, 
  consists 
  almost 
  

   entirely 
  of 
  short 
  Latin 
  descriptions 
  of 
  the 
  various 
  

   species 
  mentioned 
  (as 
  its 
  title 
  implies), 
  and 
  I 
  therefore 
  

   propose 
  to 
  transcribe 
  these, 
  and 
  add 
  thereto 
  another 
  

   careful 
  description 
  in 
  English, 
  where 
  possible, 
  from 
  his 
  

   types, 
  but 
  otherwise 
  from 
  specimens 
  in 
  my 
  possession. 
  

   It 
  will 
  be 
  seen 
  from 
  what 
  follows 
  that 
  there 
  is 
  a 
  

   tendency 
  to 
  considerable 
  variation 
  among 
  the 
  individual 
  

   species, 
  generally 
  in 
  the 
  direction 
  of 
  melanism. 
  Various 
  

   theories 
  have 
  been 
  broached 
  to 
  account 
  for 
  melanic 
  

   variation, 
  but 
  in 
  this 
  instance 
  temperature, 
  i. 
  e., 
  lowness 
  

   of 
  temperature, 
  cannot 
  be 
  the 
  cause 
  ; 
  the 
  probability 
  is 
  

   that 
  humidity 
  of 
  climate 
  (another 
  of 
  the 
  more 
  recent 
  

   propositions) 
  may 
  have 
  been 
  a 
  potent 
  factor 
  therein. 
  

  

  Passing 
  on 
  now 
  to 
  catalogue 
  the 
  collection, 
  and 
  

   following 
  the 
  general 
  order 
  of 
  Staudinger's 
  list, 
  the 
  first 
  

   insect 
  is 
  

  

  Pieris 
  brassicce 
  var. 
  WoUastoni. 
  

  

  Of 
  this 
  insect 
  there 
  is 
  a 
  considerable 
  series, 
  which, 
  I 
  

   think, 
  will 
  prove 
  it 
  worthy 
  of 
  its 
  varietal 
  name. 
  It 
  is, 
  

   moreover, 
  an 
  interesting 
  instance 
  of 
  insular 
  deviation 
  

   from 
  the 
  original 
  type. 
  In 
  the 
  deepening 
  and 
  enlarge- 
  

   ment 
  of 
  the 
  black 
  spots 
  on 
  the 
  fore 
  wings 
  it 
  forms 
  a 
  

   transition 
  between 
  brassicce 
  and 
  the 
  Canary 
  form 
  

   cheiranthi, 
  whilst 
  in 
  the 
  greener 
  colour 
  of 
  the 
  under 
  

   surface 
  of 
  the 
  hind 
  wings 
  it 
  recedes 
  in 
  the 
  contrary 
  

   direction. 
  The 
  upper 
  side 
  of 
  the 
  (? 
  is 
  practically 
  indis- 
  

   tinguishable 
  from 
  brassicce, 
  but 
  on 
  the 
  under 
  side 
  the 
  

   two 
  black 
  spots 
  are 
  larger 
  and 
  often 
  connected 
  by 
  a 
  

   dark 
  scaling, 
  making 
  them 
  almost 
  appear 
  to 
  be 
  one 
  

   large 
  patch. 
  There 
  is, 
  however, 
  a 
  greater 
  difference 
  in 
  

   hind 
  wings 
  and 
  the 
  apical 
  area, 
  which 
  in 
  brassicce 
  are 
  of 
  

   a 
  yellowish 
  grey 
  hue, 
  whilst 
  in 
  this 
  variety 
  the 
  colour 
  is 
  

   greenish 
  grey, 
  the 
  distinction 
  being 
  caused 
  to 
  some 
  

   extent 
  by 
  the 
  darker 
  grey 
  irrorations 
  of 
  v. 
  WoUastoni. 
  

   From 
  cheiranthi 
  the 
  Madeira 
  form 
  differs 
  also 
  chiefly 
  on 
  

   the 
  under 
  surface, 
  the 
  former 
  of 
  which 
  can 
  be 
  recog- 
  

   nised 
  at 
  once 
  by 
  the 
  broad 
  black 
  band 
  of 
  the 
  upper 
  

   wings 
  (formed 
  by 
  the 
  coalescence 
  of 
  the 
  two 
  black 
  

   spots), 
  and 
  also 
  by 
  the 
  deej) 
  yellowish 
  buff 
  of 
  the 
  

   secondaries. 
  

  

  The 
  ? 
  sex 
  from 
  Madeira 
  shows 
  some 
  little 
  variation. 
  

   All 
  are 
  much 
  darker 
  than 
  the 
  parent 
  species, 
  but 
  none 
  

  

  