﻿210 
  BRITISH 
  LEPIDOPTERA. 
  

  

  slightly 
  oblique 
  slope 
  on 
  metathorax, 
  near 
  together, 
  but 
  not 
  touching 
  ; 
  

   they 
  are 
  joined 
  by 
  a 
  chitinised 
  skin-area 
  that 
  is 
  hardly 
  marked 
  enough 
  

   to 
  be 
  called 
  a 
  plate 
  ; 
  tubercles 
  iii 
  and 
  iv 
  are 
  situated 
  close 
  together 
  (as 
  

   in 
  Sphingid 
  larvae) 
  on 
  a 
  single 
  plate, 
  vi 
  carries 
  a 
  single 
  weak 
  hair 
  some 
  

   little 
  distance 
  below, 
  while 
  v 
  is 
  a 
  plate 
  bearing 
  two 
  hairs 
  (probably 
  the 
  

   primary 
  seta 
  of 
  v 
  and 
  the 
  small 
  secondary 
  hair 
  that 
  is 
  generally 
  found 
  

   near 
  it) 
  ; 
  there 
  is 
  a 
  treble-haired 
  plate 
  (vii) 
  at 
  base 
  of 
  legs. 
  On 
  the 
  

   abdominal 
  segments, 
  tubercles 
  i 
  and 
  ii 
  are 
  set 
  in 
  trapezoidal 
  position, 
  

   single-haired, 
  ii 
  bearing 
  much 
  the 
  longer 
  hair 
  ; 
  iii 
  is 
  situated 
  some 
  

   little 
  distance 
  above 
  the 
  spiracle 
  ; 
  close 
  to 
  the 
  spiracle 
  the 
  usual 
  minute 
  

   tubercular 
  point 
  is 
  quite 
  noticeable, 
  the 
  point 
  being 
  larger 
  than 
  

   customary, 
  and 
  having 
  a 
  small 
  basal 
  plate. 
  The 
  spiracles 
  are 
  large, 
  

   with 
  slightly 
  raised 
  black 
  walls 
  tapering 
  upwards. 
  Tubercles 
  iv 
  and 
  v 
  

   are, 
  as 
  usual, 
  mounted 
  on 
  a 
  single 
  plate 
  beneath 
  the 
  spiracle 
  ; 
  this 
  

   plate 
  is 
  more 
  raised 
  and 
  wart-like 
  than 
  any 
  of 
  the 
  others. 
  There 
  are 
  

   also 
  two 
  marginal 
  setae 
  situated 
  a 
  short 
  distance 
  apart 
  ; 
  their 
  bases 
  are 
  

   distinct, 
  but 
  the 
  actual 
  setae 
  are 
  not 
  (Bacot). 
  Final 
  instar 
  : 
  In 
  the 
  

   last 
  instar, 
  the 
  skin-points 
  are 
  very 
  numerous, 
  dark 
  in 
  colour, 
  mostly 
  

   flat 
  or 
  round- 
  topped, 
  but 
  with 
  sharp 
  points 
  in 
  places, 
  especially 
  along 
  the 
  

   anterior 
  border 
  of 
  the 
  segments, 
  and 
  the 
  long 
  sharp 
  needle-points 
  are 
  still 
  

   found 
  ventrally, 
  especially 
  in 
  front 
  of 
  each 
  pair 
  of 
  true 
  legs. 
  The 
  

   skin-hairs 
  are 
  almost 
  universal, 
  quite 
  different 
  from 
  those 
  of 
  P. 
  

   isodactylus 
  where 
  considerable 
  areas 
  are 
  without 
  them. 
  There 
  are, 
  

   however, 
  as 
  in 
  all 
  these 
  species, 
  certain 
  small, 
  usually 
  circular, 
  areas 
  

   without 
  hairs 
  or 
  skin 
  -points 
  ; 
  these 
  are 
  generally 
  about 
  O'lmm. 
  in 
  

   diameter, 
  and 
  the 
  skin-points 
  are 
  often 
  in 
  rows 
  round 
  them. 
  Their 
  

   number 
  is 
  much 
  the 
  same 
  as 
  that 
  of 
  the 
  tubercles, 
  and 
  they 
  seem 
  to 
  

   have 
  equally 
  fixed 
  positions. 
  The 
  prolegs 
  and 
  claspers 
  have 
  eight 
  or 
  

   nine 
  hooks. 
  The 
  prothoracic 
  plate 
  is 
  dark, 
  with 
  darker, 
  puckered-looking 
  

   (depressed) 
  patch 
  near 
  each 
  outer 
  end, 
  with 
  a 
  central 
  suture 
  and 
  six 
  hairs 
  

   on 
  either 
  side 
  in 
  typical 
  disposition 
  ; 
  there 
  are 
  also 
  three 
  hairs 
  on 
  

   the 
  prespiracular 
  plate 
  and 
  two 
  on 
  one 
  plate 
  at 
  the 
  base 
  of 
  legs. 
  On 
  

   the 
  meso- 
  and 
  metathorax 
  there 
  are, 
  on 
  each 
  side, 
  four 
  plates, 
  each 
  

   with 
  two 
  hairs, 
  and 
  a 
  small 
  plate 
  with 
  one 
  (above 
  and 
  behind 
  the 
  third 
  

   large 
  one) 
  ; 
  on 
  the 
  four 
  plates 
  the 
  hairs 
  are 
  placed 
  : 
  (1) 
  trapezoidally, 
  

   (2) 
  as 
  reversed 
  trapezoidals, 
  (3) 
  upright, 
  (4) 
  horizontal. 
  On 
  the 
  abdo- 
  

   minal 
  segments, 
  i 
  and 
  ii 
  are 
  widely 
  separate, 
  trapezoidal, 
  i 
  with 
  hair 
  

   about 
  0-3mm. 
  long, 
  ii 
  and 
  iii 
  with 
  hairs 
  about 
  0-5mm., 
  iv 
  and 
  v 
  on 
  one 
  

   plate, 
  trapezoidally; 
  vi 
  may 
  carry 
  one, 
  two, 
  three, 
  or 
  four 
  hairs 
  (on 
  the 
  

   1st 
  abdominal 
  segment 
  it 
  is 
  generally 
  a 
  single 
  plate 
  with 
  two 
  hairs, 
  

   one 
  above 
  the 
  other, 
  on 
  the 
  2nd 
  abdominal, 
  it 
  has 
  usually 
  three 
  

   separate 
  hairs, 
  often 
  four 
  on 
  the 
  following 
  segments, 
  an 
  odd 
  segment 
  

   varying 
  from 
  the 
  others, 
  in 
  one 
  case 
  only 
  one 
  hair, 
  all 
  the 
  other 
  

   segments 
  having 
  two 
  or 
  more) 
  ; 
  virhas 
  the 
  usual 
  three 
  hairs 
  ; 
  viii 
  (?) 
  

   a 
  single 
  small 
  hair. 
  The 
  spiracles 
  are 
  large, 
  circular, 
  on 
  a 
  high 
  conical 
  

   base. 
  On 
  the 
  8th 
  abdominal, 
  the 
  hairs 
  of 
  ii 
  on 
  either 
  side 
  are 
  on 
  a 
  

   single 
  conjoined 
  base 
  (a 
  narrow 
  transverse 
  dark 
  plate) 
  ; 
  on 
  the 
  9th 
  

   abdominal, 
  is 
  a 
  dorsal 
  quadrangular 
  plate, 
  with 
  four 
  hairs 
  placed 
  in 
  

   square, 
  then 
  a 
  small 
  plate 
  with 
  two 
  hairs 
  trapezoidally 
  placed, 
  then 
  

   two 
  hairs 
  vertically 
  on 
  a 
  smaller 
  plate, 
  then 
  a 
  single 
  hair, 
  and, 
  finally, 
  

   a 
  very 
  small 
  hair 
  close 
  to 
  the 
  ventral 
  line. 
  The 
  anal 
  plate 
  has 
  six 
  (or 
  

   seven) 
  principal 
  hairs, 
  and 
  four 
  (or 
  three) 
  smaller 
  ones 
  (Chapman). 
  

   Short 
  general 
  descriptions 
  of 
  the 
  fullfed 
  larva 
  are 
  given 
  by 
  

  

  