﻿190 
  BEITISH 
  LEPIDOPTERA. 
  

  

  as 
  convenience 
  or 
  necessity 
  arises, 
  and 
  at 
  once 
  either 
  re-enter 
  the 
  same 
  

   stem 
  lower 
  down, 
  or 
  else 
  bore 
  into 
  a 
  fresh 
  stem 
  and 
  feed 
  downwards, 
  

   the 
  frass 
  being 
  ejected 
  through 
  the 
  entrance 
  hole. 
  A 
  single 
  stem, 
  if 
  of 
  

   any 
  length, 
  not 
  infrequently 
  contains 
  more 
  than 
  one 
  larva. 
  The 
  

   infected 
  plants 
  generally 
  look 
  rather 
  sickly, 
  but 
  the 
  presence 
  of 
  the 
  

   larvae 
  therein 
  may 
  most 
  readily 
  be 
  detected 
  by 
  the 
  pellets 
  of 
  moist 
  

   pale 
  frass 
  seen 
  clustered 
  beside 
  the 
  entrance 
  hole. 
  The 
  larvae 
  of 
  the 
  

   second 
  brood 
  are 
  far 
  easier 
  to 
  find 
  than 
  those 
  of 
  the 
  first, 
  because, 
  in 
  

   July 
  and 
  August, 
  the 
  Senecio 
  stems 
  are 
  so 
  very 
  much 
  taller 
  than 
  in 
  

   May, 
  and, 
  being 
  then 
  comparatively 
  clear 
  of 
  the 
  surrounding 
  herbage, 
  

   are 
  more 
  readily 
  seen 
  and 
  examined, 
  and 
  bring 
  the 
  larval 
  traces 
  

   considerably 
  nearer 
  the 
  eye. 
  The 
  larvae 
  of 
  both 
  broods 
  feed 
  up 
  very 
  

   irregularly, 
  and, 
  probably, 
  in 
  early 
  June 
  and 
  early 
  August 
  of 
  each 
  year, 
  

   larvae, 
  pupae, 
  and 
  imagines 
  could 
  be 
  collected 
  together 
  on 
  the 
  same 
  

   date 
  and 
  in 
  the 
  same 
  spot. 
  This 
  I 
  have 
  done 
  on 
  three 
  separate 
  

   occasions, 
  viz., 
  May 
  31st, 
  1890 
  ; 
  August 
  2nd, 
  1890 
  ; 
  and 
  August 
  1st, 
  

   1891, 
  although 
  all 
  my 
  expeditions 
  have 
  been 
  timed 
  to 
  secure 
  the 
  insect 
  

   before 
  it 
  reached 
  the 
  perfect 
  state. 
  On 
  August 
  1st, 
  1891, 
  and 
  July 
  

   28th, 
  1892, 
  many 
  larvae 
  were 
  found, 
  in 
  nature, 
  dead 
  in 
  their 
  burrows 
  

   inside 
  the 
  stems, 
  evidently 
  from 
  disease. 
  In 
  1891, 
  the 
  previous 
  

   weather 
  was 
  exceedingly 
  wet, 
  whilst 
  in 
  1892 
  it 
  was 
  exceptionally 
  fine 
  

   and 
  hot 
  ! 
  My 
  notes 
  make 
  mention 
  of 
  some 
  larvae 
  being 
  ichneumoned, 
  

   but 
  the 
  parasites 
  were 
  not 
  preserved." 
  Stange 
  observes 
  (Stett. 
  

   Ent. 
  Zeitij., 
  1882, 
  p. 
  514) 
  that 
  the 
  larvae 
  of 
  the 
  first 
  generation 
  may 
  

   be 
  found 
  in 
  Friedland 
  in 
  May, 
  mining 
  at 
  first 
  down 
  the 
  midrib 
  of 
  a 
  

   radical 
  leaf 
  of 
  Senecio 
  (? 
  aquaticus), 
  and 
  usually 
  with 
  head 
  directed 
  

   towards 
  the 
  leaf-base 
  ; 
  later, 
  it 
  enters 
  the 
  central 
  shoot 
  and 
  the 
  upper 
  

   part 
  of 
  the 
  root 
  which 
  it 
  eats 
  out 
  in 
  a 
  downward 
  direction 
  ; 
  the 
  

   excrement 
  is 
  heaped 
  up 
  on 
  the 
  central 
  shoot. 
  The 
  larva 
  of 
  the 
  second 
  

   generation 
  lives 
  in 
  the 
  stem 
  and 
  betrays 
  its 
  presence 
  by 
  the 
  excrement 
  

   which 
  protrudes 
  from 
  the 
  entrance 
  hole. 
  

  

  Larva. 
  — 
  First 
  instarf 
  (newly-hatched) 
  : 
  A 
  minute 
  yellow 
  scrap, 
  

   barely 
  1mm. 
  in 
  length, 
  with 
  large 
  black 
  head, 
  nearly 
  twice 
  the 
  width 
  

   of 
  the 
  body 
  of 
  the 
  larva 
  ; 
  a 
  large 
  black 
  prothoracic 
  plate 
  ; 
  a 
  faintly 
  

   tinted 
  dark 
  anal 
  plate. 
  The 
  hairs 
  are 
  nearly 
  half 
  the 
  width 
  of 
  the 
  

   body 
  in 
  length 
  ; 
  that 
  on 
  tubercle 
  i 
  directed 
  forwards, 
  on 
  ii 
  backwards, 
  

   on 
  iii 
  forwards 
  ; 
  iv 
  and 
  v 
  present 
  one 
  very 
  long 
  hair 
  directed 
  nearly 
  

   backwards 
  (arising 
  from 
  iv), 
  and 
  a 
  shorter 
  one 
  above 
  and 
  in 
  front 
  of 
  

   it 
  directed 
  rather 
  forwards 
  (arising 
  from 
  v) 
  ; 
  these 
  are 
  quite 
  distinct 
  

   from 
  each 
  other 
  and 
  on 
  separate 
  bases. 
  There 
  appears 
  to 
  be 
  no 
  hair 
  

   between 
  these 
  and 
  those 
  at 
  the 
  base 
  of 
  prolegs 
  (vii). 
  On 
  the 
  meso- 
  

   and 
  metathorax, 
  i, 
  ii 
  and 
  iii 
  are 
  as 
  on 
  the 
  abdomen, 
  except 
  that 
  i 
  is 
  

   nearly 
  as 
  far 
  back 
  as 
  ii 
  on 
  metathorax, 
  and 
  quite 
  so 
  on 
  the 
  mesothorax, 
  

   and 
  in 
  both 
  cases 
  they 
  are 
  close 
  together 
  ; 
  there 
  is 
  an 
  accessory 
  

   tubercle 
  above 
  and 
  behind 
  iii 
  (? 
  the 
  usual 
  second 
  pair 
  on 
  thorax) 
  ; 
  

   below 
  these 
  a 
  long 
  hair 
  (? 
  solitary). 
  The 
  spiracles 
  are 
  very 
  large 
  and 
  

   project 
  very 
  markedly. 
  The 
  general 
  surface 
  is 
  very 
  smooth, 
  and 
  no 
  

   hairs 
  or 
  hair-points 
  can 
  be 
  seen, 
  but 
  there 
  is 
  some 
  trace 
  of 
  sub- 
  

   segmentation. 
  The 
  hairs 
  are 
  nearly 
  black 
  with 
  slightly 
  expanded 
  

  

  f 
  When 
  young 
  the 
  larva 
  is 
  white, 
  and 
  is 
  peculiarly 
  long 
  and 
  slender, 
  thus 
  

   forming, 
  both 
  in 
  colour 
  and 
  shape, 
  a 
  remarkable 
  contrast 
  with 
  the 
  green 
  hue 
  and 
  

   short, 
  stout 
  proportions 
  assumed 
  as 
  it 
  approaches 
  maturity 
  (Bankes). 
  

  

  