﻿STENOPTILIA 
  PTERODACTYLA. 
  371 
  

  

  long 
  and 
  slender 
  ; 
  greatest 
  girth 
  at 
  4th 
  abdominal 
  segment 
  ; 
  it 
  tapers 
  

   gently 
  from 
  this 
  towards 
  the 
  rather 
  small 
  head 
  and 
  towards 
  the 
  

   pointed 
  anus 
  ; 
  segments 
  somewhat 
  swollen 
  ; 
  well-marked 
  segmental 
  

   incisions. 
  Head 
  rounded, 
  polished, 
  of 
  a 
  black 
  hue, 
  with 
  a 
  few 
  whitish 
  

   hairs 
  ; 
  the 
  prothoracic 
  shield 
  and 
  anal 
  plate 
  are 
  of 
  chitinous 
  

   appearance, 
  dark 
  smoky-green, 
  the 
  former 
  with 
  the 
  two 
  depressed 
  

   dark-coloured 
  spots 
  as 
  in 
  the 
  later 
  stages. 
  In 
  addition 
  to 
  the 
  two 
  

   large 
  subsegments 
  that 
  are 
  present 
  in 
  the 
  next 
  instar, 
  there 
  

   is 
  a 
  small, 
  poorly-marked, 
  central 
  subsegrnent 
  situated 
  centrally 
  

   between 
  the 
  anterior 
  and 
  posterior 
  dorsal 
  tubercles, 
  while, 
  on 
  

   the 
  meso- 
  and 
  metathorax 
  there 
  is, 
  in 
  addition, 
  a 
  very 
  distinctly 
  

   marked, 
  but 
  small, 
  subsegrnent 
  in 
  front 
  of 
  the 
  three 
  poorly-marked 
  

   ones, 
  which 
  make 
  up 
  the 
  bulk 
  of 
  the 
  segments. 
  The 
  skin 
  is 
  pale 
  

   (whitish 
  or 
  yellowish), 
  glistening 
  in 
  appearance, 
  with 
  a 
  well-marked, 
  

   and 
  relatively 
  coarse, 
  coat 
  of 
  brown 
  spicules. 
  The 
  prolegs 
  are 
  tall 
  and 
  

   slender 
  ; 
  the 
  true 
  legs 
  dark 
  smoke-coloured, 
  and 
  the 
  anal 
  claspers 
  show 
  

   some 
  tendency 
  to 
  extend 
  backward 
  as 
  in 
  the 
  older 
  larvae, 
  and 
  are 
  

   chitinous 
  in 
  appearance. 
  The 
  colour 
  is 
  white 
  with 
  a 
  yellow 
  medio- 
  

   dorsal 
  band 
  ; 
  also 
  a 
  very 
  broad 
  and 
  much 
  broken 
  subdorsal 
  one, 
  

   extending 
  downwards, 
  as 
  detached 
  streaks 
  and 
  blotches, 
  as 
  far 
  as 
  the 
  

   spiracular 
  level 
  ; 
  below 
  this, 
  the 
  white 
  extends 
  as 
  far 
  as 
  the 
  ventral 
  

   area, 
  which 
  itself 
  is 
  of 
  a 
  dull, 
  and 
  less 
  vivid, 
  white. 
  The 
  spiracles 
  are 
  

   large 
  and 
  conspicuous, 
  of 
  a 
  pale 
  brown 
  colour, 
  but 
  not 
  much 
  raised 
  for 
  

   a 
  plume 
  larva 
  ; 
  as 
  usual 
  the 
  prothoracic 
  and 
  8th 
  abdominal 
  spiracles 
  

   are 
  larger 
  than 
  the 
  others. 
  The 
  tubercles 
  are 
  cone-shaped 
  buttons, 
  each 
  

   bearing 
  one, 
  long, 
  pale, 
  white 
  hair, 
  tapering, 
  but 
  at 
  the 
  same 
  time 
  

   slightly 
  knobbed 
  at 
  the 
  tip, 
  and 
  minutely 
  thorned. 
  There 
  are, 
  in 
  

   addition, 
  a 
  few 
  short, 
  dark-coloured 
  (black 
  or 
  dark 
  brown), 
  knobbed 
  

   bristles, 
  apparently 
  correlated 
  with 
  the 
  primary 
  hairs, 
  but 
  not 
  always 
  

   in 
  close 
  proximity. 
  On 
  the 
  meso- 
  and 
  metathorax 
  the 
  dorsal 
  tubercles 
  

   i 
  and 
  ii 
  are 
  in 
  close 
  proximity, 
  but 
  their 
  bases 
  do 
  not 
  touch 
  ; 
  they 
  are 
  

   set 
  somewhat 
  obliquely, 
  i 
  inner, 
  ii 
  outer 
  ; 
  iii 
  and 
  iv 
  are 
  situated 
  close 
  

   together, 
  their 
  bases 
  almost, 
  or 
  quite, 
  touching 
  ; 
  below 
  these, 
  rather 
  

   posteriorly, 
  there 
  is 
  a 
  weak 
  subprimary 
  hair, 
  and, 
  in 
  front 
  of 
  this, 
  a 
  

   strong 
  v, 
  and 
  near 
  it 
  the 
  usual 
  subprimary 
  vi 
  ; 
  vii 
  has 
  two 
  hairs. 
  

   On 
  the 
  abdominal 
  segments, 
  i 
  and 
  ii 
  are 
  set 
  trapezoidally 
  and 
  are 
  well- 
  

   separated, 
  iii 
  is 
  close 
  above 
  the 
  spiracle, 
  while 
  iv 
  and 
  v, 
  with 
  bases 
  

   clearly 
  separated 
  but 
  close 
  together, 
  are 
  in 
  the 
  usual 
  position 
  beneath 
  

   it 
  ; 
  below 
  these 
  is 
  vi, 
  bearing 
  a 
  single 
  hair, 
  and 
  a 
  double- 
  or 
  treble- 
  

   haired 
  marginal 
  vii 
  just 
  above 
  the 
  prolegs, 
  on 
  the 
  segments 
  bearing 
  

   prolegs, 
  three-haired, 
  but 
  on 
  the 
  other 
  abdominals 
  only 
  two-haired. 
  

   The 
  black 
  bristles 
  above 
  referred 
  to 
  are 
  — 
  one 
  on 
  either 
  side 
  of 
  i, 
  and 
  

   one 
  on 
  either 
  side 
  of 
  ii, 
  making 
  four 
  dorsal 
  rows 
  ; 
  occasionally 
  these 
  

   are 
  either 
  missing, 
  or 
  very 
  pale-coloured 
  and 
  inconspicuous; 
  usually 
  

   this 
  happens 
  to 
  the 
  row 
  nearest 
  the 
  middle 
  line 
  ; 
  there 
  is 
  a 
  similar 
  

   secondary 
  hair 
  situated 
  immediately 
  behind 
  iii. 
  and 
  another 
  posterior 
  

   to 
  the 
  spiracle 
  (occupying 
  about 
  the 
  1 
  position 
  of 
  the 
  secondary 
  wart 
  in 
  

   the 
  larva 
  of 
  Porrittia 
  galactodactyla, 
  etc.). 
  On 
  the 
  5th 
  abdominal, 
  but 
  

   on 
  the 
  right 
  side 
  only, 
  there 
  is, 
  in 
  this 
  particular 
  larva, 
  an 
  additional 
  

   bristle 
  (of 
  only 
  about- 
  half 
  the 
  normal 
  length, 
  however) 
  between 
  the 
  

   postspiracular 
  ami 
  the 
  one 
  beneath 
  ii. 
  A 
  well-marked 
  lateral 
  flange 
  is 
  

   present 
  (Bacot, 
  May 
  4th, 
  1901). 
  .' 
  Fourth 
  instar: 
  Complete 
  change 
  from 
  

   generalised 
  to 
  specialised 
  conditions; 
  tmm.-6mm. 
  in 
  length, 
  oompara- 
  

  

  