﻿PLATYPTILIA 
  ISODACTYLUS. 
  198 
  

  

  than 
  those 
  he 
  described 
  in 
  August, 
  1871, 
  being 
  perhaps 
  the 
  least 
  trifle 
  

   larger, 
  the 
  proportions, 
  structure, 
  and 
  details 
  all 
  exactly 
  similar, 
  the 
  

   general 
  colour 
  of 
  the 
  skin 
  only 
  being 
  a 
  little 
  different, 
  these 
  being 
  

   more 
  yellowish 
  and 
  less 
  greenish. 
  One 
  individual 
  was 
  flesh-coloured 
  

   as 
  far 
  as 
  the 
  7th 
  segment, 
  the 
  remainder 
  being 
  of 
  a 
  pale, 
  faintly 
  

   ochreous, 
  greenish-yellow. 
  

  

  Foodplants. 
  — 
  Senecio 
  aquations 
  (Barrett), 
  [Senecio 
  nemorensis 
  (Snel- 
  

   len).] 
  

  

  Puparium. 
  — 
  The 
  mode 
  of 
  pupation 
  of 
  the 
  larvae 
  fullfed 
  in 
  May 
  and 
  

   those 
  fullfed 
  in 
  August 
  differs 
  greatly. 
  Those 
  of 
  the 
  early 
  brood 
  come 
  

   out 
  of 
  their 
  larval 
  burrows 
  and 
  form 
  outside 
  puparia, 
  spinning 
  up 
  in 
  

   leaves,* 
  etc., 
  those 
  of 
  the 
  late 
  brood 
  make 
  a 
  hollow 
  in 
  the 
  stem 
  of 
  the 
  

   foodplant 
  and 
  pupate 
  therein. 
  Describing 
  the 
  pupation-habit 
  of 
  the 
  

   latter, 
  Barrett 
  says 
  that, 
  '' 
  when 
  nearly 
  fullfed, 
  the 
  larva 
  burrows 
  into 
  

   the 
  thick 
  main 
  stem 
  of 
  the 
  plant, 
  hollows 
  out 
  a 
  space 
  of 
  considerable 
  

   size 
  in 
  which 
  to 
  pupate, 
  the 
  head 
  of 
  the 
  pupa 
  being 
  in 
  every 
  case 
  

   placed 
  against 
  the 
  round 
  hole 
  that 
  is 
  left 
  by 
  the 
  larva 
  for 
  the 
  extrusion 
  

   of 
  excrement. 
  The 
  pupa 
  lies 
  perfectly 
  free 
  in 
  the 
  burrow, 
  the 
  anal 
  

   segment 
  not 
  being 
  attached 
  to 
  the 
  usual 
  button 
  of 
  silk." 
  Describing 
  

   the 
  pupation-habit 
  of 
  the 
  early, 
  or 
  spring, 
  larvae, 
  Chapman 
  says 
  : 
  "When 
  

   made 
  in 
  a 
  folded 
  leaf, 
  the 
  edges 
  of 
  Avhich 
  cannot 
  be 
  got 
  together 
  (or 
  

   rather 
  the 
  face, 
  as 
  the 
  leaf 
  is 
  too 
  large 
  to 
  be 
  occupied 
  to 
  the 
  edges, 
  and 
  

   is 
  also 
  rather 
  stiff), 
  the 
  cocoon 
  is 
  made 
  in 
  the 
  fold, 
  and 
  there 
  is 
  a 
  good 
  

   deal 
  of 
  loose 
  silk 
  inside, 
  especially 
  basally, 
  forming 
  a 
  sort 
  of 
  loose 
  

   pocket 
  for 
  the 
  abdominal 
  end 
  of 
  the 
  pupa, 
  the 
  exposed 
  silken 
  surface 
  

   is 
  very 
  various 
  in 
  shape 
  and 
  area, 
  as 
  may 
  be 
  necessary 
  to 
  complete 
  the 
  

   enclosure, 
  but 
  there 
  seems 
  to 
  be 
  generally 
  a 
  piece, 
  some 
  2mm. 
  or 
  3mm. 
  

   wide, 
  by 
  8mm. 
  or 
  10mm. 
  long, 
  at 
  the 
  head 
  end, 
  at 
  which 
  it 
  may 
  stretch 
  

   out 
  another 
  6mm. 
  or 
  so, 
  as 
  a 
  light 
  network 
  for 
  emergence, 
  and, 
  through 
  

   this, 
  the 
  front 
  of 
  the 
  pupa 
  may 
  be 
  seen. 
  The 
  rest 
  of 
  the 
  silken 
  surface 
  

   is 
  strong, 
  thick 
  and 
  opaque, 
  and 
  looks, 
  as 
  it 
  is, 
  quite 
  equal 
  to 
  holding 
  

   the 
  thick 
  fleshy 
  leaf 
  in 
  a 
  fold. 
  Along 
  the 
  margin, 
  where 
  the 
  silk 
  joins 
  

   the 
  leaf, 
  some 
  scraps 
  of 
  leaf 
  are 
  bitten 
  out, 
  and 
  these 
  are 
  the 
  little 
  brown 
  

   (now, 
  of 
  course, 
  faded 
  and 
  dead) 
  points, 
  with 
  which 
  the 
  silk 
  of 
  the 
  cocoon 
  

   is 
  studded. 
  This 
  arrangement 
  seems 
  to 
  be 
  to 
  allow 
  the 
  leaf 
  to 
  open 
  

   freely. 
  The 
  typical 
  situation 
  (not 
  always 
  adopted) 
  seems 
  to 
  be 
  on 
  the 
  

   midrib 
  of 
  the 
  leaf 
  close 
  to 
  the 
  petiole, 
  and 
  the 
  cocoon 
  is 
  probably 
  made 
  

   before 
  the 
  leaf 
  is 
  fully 
  expanded, 
  so 
  that 
  little 
  drawing 
  together 
  has 
  to 
  

   be 
  done, 
  but, 
  as 
  the 
  expansion 
  of 
  the 
  leaf 
  proceeds, 
  some 
  holding 
  together 
  

   has 
  to 
  be 
  accomplished. 
  This 
  nibbled 
  margin 
  meets 
  the 
  difficulty 
  in 
  two 
  

   ways, 
  viz., 
  by 
  giving 
  a 
  rough 
  surface 
  to 
  which 
  the 
  silk 
  adheres 
  much 
  more 
  

   firmly 
  than 
  to 
  the 
  smooth 
  face 
  of 
  the 
  leaf, 
  and, 
  by 
  weakening 
  the 
  leaf, 
  allows 
  

   a 
  reverse 
  bend 
  to 
  occur 
  here, 
  and 
  so 
  relieves 
  the 
  tension 
  (May 
  21st-30th, 
  

   1904)." 
  Bankes 
  writes 
  that 
  "the 
  pupae 
  of 
  the 
  first 
  brood 
  may 
  be 
  found, 
  

   in 
  nature, 
  either 
  in 
  the 
  final 
  burrow 
  made 
  by 
  the 
  larva 
  inside 
  the 
  main 
  

   stem 
  of 
  Senecio 
  aquaticus, 
  or 
  else 
  in 
  a 
  thin 
  silken, 
  blister-like 
  cocoon, 
  

   spun 
  on 
  the 
  upper 
  surface 
  of 
  a 
  leaf 
  of 
  the 
  foodplant, 
  or 
  of 
  some 
  other 
  

   neighbouring 
  plant, 
  such 
  as 
  Ranunculus, 
  the 
  loaf 
  being 
  a 
  little 
  drawn 
  

  

  * 
  The 
  pupation 
  habits 
  of 
  the 
  spring 
  larva 
  wore 
  first 
  noted 
  by 
  Buckler, 
  who 
  

   writes 
  (Larvae, 
  etc., 
  ix., 
  p. 
  346) 
  : 
  " 
  Larvee 
  of 
  the 
  early 
  brood 
  were, 
  en 
  May 
  10th. 
  

   1872, 
  mining 
  in 
  the 
  stems 
  of 
  Senecio 
  aquaticus, 
  but 
  one 
  of 
  tbom. 
  apparently 
  

   Eullfed, 
  has 
  slightly 
  drawn 
  the 
  top 
  of 
  a 
  leaf 
  together, 
  and 
  in 
  the 
  oorner 
  thus 
  formed 
  

   has 
  spun 
  a 
  web." 
  

  

  