﻿100 
  BRITISH 
  LEPIDOPTERA. 
  

  

  Hofmann 
  observes 
  (Die 
  deutsch. 
  Pterophorinen, 
  etc., 
  pp. 
  14 
  et 
  seq.) 
  

   that 
  the 
  head, 
  mouthparts, 
  antennas, 
  and 
  ocelli 
  of 
  the 
  larva 
  show 
  (without 
  

   microscopical 
  examination) 
  no 
  deviation 
  from 
  the 
  forms 
  usual 
  in 
  

   lepidopterous 
  larvae. 
  The 
  globular 
  or 
  heart-shaped 
  head 
  is 
  usually 
  

   very 
  small, 
  and 
  can 
  be 
  easily 
  withdrawn 
  into 
  the 
  prothorax 
  ; 
  the 
  

   antennas 
  are 
  very 
  short, 
  and 
  the 
  labium 
  is 
  often 
  prolonged 
  into 
  a 
  long 
  

   spindle. 
  The 
  chitinous 
  prothoracic 
  shield 
  and 
  anal 
  plate 
  are 
  very 
  

   frequent 
  in 
  young 
  larvae, 
  and, 
  in 
  some 
  groups, 
  are 
  retained 
  throughout 
  

   life, 
  whilst 
  in 
  others 
  they 
  disappear 
  with 
  the 
  last 
  moult. 
  The 
  spiracles 
  

   are 
  small 
  but 
  particularly 
  noticeable, 
  on 
  account 
  of 
  their 
  being 
  placed 
  

   much 
  higher 
  dorsally 
  than 
  is 
  usually 
  the 
  case 
  with 
  other 
  larvae. 
  The 
  

   true 
  legs 
  are 
  fairly 
  normal 
  ; 
  the 
  prolegs, 
  however, 
  are 
  very 
  variable, 
  in 
  

   some 
  groups 
  long 
  and 
  thin, 
  recalling 
  those 
  of 
  certain 
  Pyralids 
  ; 
  the 
  

   hooklets 
  are 
  arranged 
  in 
  a 
  semicircle, 
  the 
  number 
  of 
  which 
  vary 
  in 
  

   different 
  species, 
  e.g., 
  Oxyptilus 
  kieracii, 
  0. 
  pilosellae, 
  etc. 
  ; 
  in 
  some 
  species 
  

   the 
  modification 
  towards 
  obsolescence 
  in 
  the 
  prolegs 
  is 
  most 
  marked, 
  

   e.g., 
  Adaina 
  microdactyla. 
  He 
  further 
  notes 
  that 
  much 
  of 
  this 
  larval 
  

   diversity 
  appears 
  to 
  depend 
  less 
  on 
  a 
  great 
  generic 
  difference, 
  than 
  

   on 
  the 
  mode 
  of 
  life 
  of 
  the 
  larvae 
  ; 
  thus 
  the 
  allied 
  kieracii 
  and 
  pilosellae 
  

   on 
  the 
  one 
  hand, 
  and 
  scarodactyla 
  and 
  tephradactyla 
  in 
  another 
  direction, 
  

   offer 
  quite 
  different 
  larval 
  types. 
  

  

  The 
  plume 
  larvae 
  present 
  very 
  great 
  variation 
  — 
  from 
  nearly 
  smooth 
  

   to 
  very 
  hairy 
  — 
  and 
  this 
  stage 
  furnishes 
  many 
  excellent 
  characters 
  for 
  

   classification, 
  although, 
  at 
  present, 
  it 
  must 
  be 
  confessed 
  the 
  differences 
  

   are 
  not 
  too 
  thoroughly 
  understood, 
  and 
  many 
  of 
  the 
  adult 
  larvae 
  are 
  

   highly 
  specialised. 
  The 
  more 
  marked 
  characters 
  (not 
  necessarily 
  

   specialised 
  or 
  particularly 
  Alucitid 
  characters) 
  that 
  early 
  force 
  themselves 
  

   on 
  the 
  notice 
  of 
  the 
  student 
  are 
  : 
  (1) 
  The 
  raised 
  spiracles, 
  a 
  most 
  striking 
  

   feature, 
  and 
  a 
  very 
  constant 
  one 
  throughout 
  the 
  superfamily, 
  but 
  still 
  

   subject 
  to 
  great 
  variation. 
  (2) 
  The 
  highly-developed 
  covering 
  of 
  

   spicules 
  (of 
  course 
  a 
  generalised 
  character) 
  which 
  is 
  found 
  pretty 
  

   generally 
  throughout 
  the 
  group, 
  after 
  the 
  first 
  moult, 
  but 
  is 
  subject 
  to 
  

   great 
  modification." 
  (3) 
  The 
  great 
  difference 
  in 
  the 
  position 
  of 
  the 
  sub- 
  

   spiracular 
  tubercles 
  in 
  the 
  Agdistids 
  compared 
  with 
  those 
  of 
  the 
  Alucitid 
  

   larvae. 
  (4) 
  The 
  great 
  difference 
  in 
  the 
  character 
  of 
  the 
  tubercles, 
  

   varying 
  from 
  simple 
  single 
  -haired 
  chitinous 
  buttons, 
  to 
  complicated 
  

   many-haired 
  warts, 
  or 
  tall 
  horn-like 
  processes 
  on 
  which 
  the 
  setae 
  are 
  

   borne. 
  (5) 
  The 
  presence 
  of 
  accessory 
  or 
  secondary 
  tubercular 
  hairs, 
  

   distinct 
  from 
  the 
  usual 
  tubercular 
  groups, 
  and 
  the 
  wart-like 
  structures 
  

   they 
  generally 
  form. 
  (6) 
  The 
  presence 
  of 
  scattered 
  skin-hairs 
  (another 
  

   character 
  found 
  in 
  widely 
  different 
  superfamilies). 
  

  

  The 
  peculiar 
  raised 
  character 
  of 
  the 
  larval 
  spiracles 
  is 
  most 
  note- 
  

   worthy. 
  Those 
  on 
  the 
  prothorax 
  and 
  8th 
  abdominal 
  segment 
  

   resemble 
  those 
  of 
  other 
  lepidopterous 
  larvae 
  in 
  being 
  much 
  larger 
  than 
  

   the 
  others, 
  and 
  presenting 
  the 
  special 
  peculiarities, 
  therefore, 
  more 
  

   visibly. 
  In 
  most 
  Alucitid 
  species, 
  the 
  spiracles 
  present 
  a 
  smooth, 
  

   conical 
  mound 
  of 
  some 
  height, 
  with 
  the 
  spiracle 
  proper 
  at 
  the 
  apex. 
  

   This 
  feature 
  is 
  more 
  conspicuous, 
  perhaps, 
  in 
  the 
  Platyptiliine 
  (smooth) 
  

   than 
  in 
  the 
  Alucitine 
  (hairy) 
  section 
  of 
  the 
  group. 
  This 
  is 
  not, 
  

  

  * 
  The 
  absence 
  of 
  spicules 
  is 
  unusual 
  in 
  lepidopterous 
  larvae, 
  still 
  their 
  general 
  

   absence 
  in 
  the 
  first 
  instar, 
  and 
  their 
  well-developed 
  character 
  in 
  the 
  later 
  instars, 
  in 
  

   this 
  superfamily, 
  is 
  interesting. 
  

  

  