﻿GENERAL 
  . 
  BIOLOGICAL 
  CHARACTERS 
  OF 
  THE 
  ALUCITIDES. 
  119 
  

  

  of 
  neuration 
  in 
  the 
  group 
  were 
  not 
  so 
  wholly 
  dependent 
  on 
  the 
  modifica- 
  

   tion 
  of 
  the 
  wing-shape, 
  but, 
  as 
  a 
  matter 
  of 
  fact, 
  Meyrick's 
  results, 
  as 
  tested 
  

   by 
  other 
  characters 
  (especially 
  those 
  derived 
  from 
  the 
  early 
  stages), 
  show 
  

   that 
  the 
  neuration 
  taken 
  alone 
  (or 
  not 
  properly 
  interpreted) 
  may 
  be 
  a 
  

   most 
  misleading 
  character, 
  as 
  witness 
  the 
  union 
  of 
  two 
  so 
  divergent 
  

   species 
  as 
  microdactyla 
  and 
  litnaeclactyla 
  (phaeodactyla) 
  in 
  Marasmarcha. 
  

   As 
  to 
  the 
  actual 
  neuration 
  of 
  the 
  Alucitids, 
  Meyrick 
  notes 
  (Trans. 
  Ent. 
  

   Soc. 
  Lond., 
  1886, 
  p. 
  3) 
  that 
  "it 
  is 
  necessary 
  to 
  examine 
  the 
  older 
  and 
  

   more 
  ancestral 
  genera, 
  in 
  which 
  the 
  fission 
  of 
  the 
  wings 
  has 
  not 
  

   proceeded 
  far, 
  to 
  distinguish 
  the 
  Pyralid 
  type 
  of 
  neuration," 
  * 
  and 
  

   adds 
  that 
  " 
  in 
  the 
  more 
  advanced 
  form 
  is 
  found 
  a 
  rapid 
  degradation, 
  

   causing 
  the 
  obsolescence 
  of 
  most 
  of 
  the 
  nervures, 
  so 
  that 
  the 
  affinity 
  of 
  

   these 
  forms, 
  if 
  they 
  stood 
  alone, 
  could 
  not 
  possibly 
  be 
  demonstrated. 
  

   The 
  progressive 
  obsolescence 
  of 
  the 
  veins 
  takes 
  place 
  as 
  follows, 
  all 
  the 
  

   stages 
  occurring 
  in 
  different 
  genera 
  : 
  The 
  fission 
  of 
  the 
  wings, 
  

   occurring 
  opposite 
  the 
  middle 
  of 
  the 
  cell, 
  causes 
  5 
  and 
  6 
  in 
  both 
  wings 
  

   to 
  become 
  very 
  short, 
  but 
  these 
  veins, 
  with 
  the 
  transverse 
  vein, 
  though 
  

   becoming 
  very 
  indistinct 
  and 
  feeble, 
  do 
  not 
  disappear, 
  except 
  in 
  the 
  

   extreme 
  type 
  Cosmoclostis, 
  where 
  the 
  fissure 
  extends 
  more 
  than 
  two- 
  

   thirds 
  of 
  the 
  length 
  of 
  the 
  wing. 
  In 
  the 
  forewings, 
  2 
  and 
  3 
  then 
  

   become 
  gradually 
  coincident 
  with 
  4, 
  and 
  7, 
  9, 
  10 
  and 
  11 
  with 
  8 
  ; 
  in 
  the 
  

   hindwings 
  3 
  becomes 
  coincident 
  with 
  4, 
  and, 
  in 
  the 
  extreme 
  type, 
  2 
  also 
  

   coincides 
  with 
  4 
  and 
  8 
  with 
  7. 
  The 
  neuration 
  is 
  thus 
  finally 
  reduced 
  

   to 
  four 
  simple 
  independent 
  veins 
  in 
  the 
  forewings 
  and 
  three 
  in 
  the 
  

   hindwings," 
  etc. 
  

  

  The 
  long 
  and 
  slender 
  legs 
  are 
  very 
  characteristic, 
  the 
  spurs 
  

   being 
  particularly 
  noticeable. 
  The 
  fore 
  tibiae 
  are 
  provided 
  with 
  a 
  

   tibial 
  epiphysis 
  on 
  the 
  inside 
  towards 
  the 
  lower 
  end, 
  while 
  the 
  

   middle 
  tibiae 
  have 
  a 
  pair 
  of 
  spurs 
  at 
  the 
  end, 
  and 
  the 
  hind 
  tibiae 
  

   two 
  pairs, 
  one 
  at 
  the 
  bottom, 
  the 
  other 
  some 
  distance 
  up. 
  The 
  

   scaling, 
  however, 
  is 
  sometimes 
  a 
  very 
  marked 
  feature, 
  and 
  the 
  scales 
  are 
  

   sometimes 
  collected 
  into 
  tufts 
  around 
  the 
  bases 
  of 
  the 
  spurs. 
  The 
  most 
  

   extreme 
  modification 
  in 
  this 
  direction, 
  however, 
  is 
  that 
  presented 
  by 
  

   Crocydoscelus 
  ferruyineuw, 
  Walsm. 
  (Trans. 
  Ent. 
  Soc. 
  Loud., 
  1897, 
  pi. 
  ii., 
  

   fig. 
  1), 
  described 
  (op. 
  cit., 
  p. 
  35) 
  as 
  having 
  " 
  the 
  anterior 
  pair 
  with 
  

   a 
  wide 
  tuft 
  at 
  the 
  end 
  of 
  the 
  tibiae 
  ; 
  middle 
  pair 
  with 
  a 
  similar 
  tuft 
  ; 
  

   posterior 
  pair 
  with 
  three 
  outspreading 
  fan-like 
  tufts, 
  the 
  first 
  small, 
  

   near 
  the 
  base 
  of 
  the 
  tibiae, 
  the 
  other 
  two 
  much 
  larger, 
  arising 
  above 
  

   the 
  base 
  of 
  the 
  spurs 
  ; 
  the 
  inner 
  spurs 
  much 
  longer 
  than 
  the 
  outer, 
  

   slightly 
  clothed 
  ; 
  the 
  outer 
  spurs 
  densely 
  clothed." 
  

  

  As 
  a 
  summary 
  of 
  the 
  chief 
  characters 
  and 
  features 
  of 
  the 
  Alucitid 
  

   imago, 
  we 
  quote 
  Fernald's 
  excellent 
  description 
  (Pterophondae 
  of 
  North 
  

   America, 
  pp. 
  9 
  ct 
  set}.): 
  

  

  They 
  are 
  small, 
  slim 
  insects, 
  with 
  long- 
  slender 
  legs 
  ami 
  long 
  narrow 
  fore- 
  

   wings, 
  cut 
  by 
  a 
  fissure 
  extending 
  in 
  from 
  the 
  middle 
  of 
  the 
  outer 
  margin 
  between 
  

   veins 
  4 
  and 
  7, 
  to 
  from 
  one-fourth 
  to 
  one-half 
  of 
  the 
  length 
  of 
  the 
  wing. 
  The 
  parts 
  

   on 
  each 
  side 
  of 
  the 
  fissure 
  are 
  called 
  lobes, 
  the 
  anterior 
  one 
  being 
  called 
  the 
  first, 
  and 
  

   the 
  other 
  the 
  second, 
  lobe. 
  In 
  some 
  of 
  the 
  genera 
  these 
  lobes 
  are 
  narrow 
  and 
  

   pointed, 
  while 
  in 
  others 
  they 
  are 
  well-developed 
  and 
  present 
  two 
  well-marked 
  angles 
  

   on 
  each, 
  which 
  are 
  called 
  the 
  apex 
  and 
  anal 
  angle. 
  The 
  normal 
  number 
  of 
  veins 
  

   in 
  the 
  forewings 
  is 
  12, 
  but 
  this 
  number 
  is 
  reduced 
  in 
  many 
  of 
  the 
  species. 
  Vein 
  I 
  

   is 
  feebly 
  forked 
  at 
  the 
  base, 
  at 
  least/ 
  in 
  some 
  of 
  the 
  species, 
  and 
  the 
  cross-vein 
  and 
  

   veins 
  5 
  and 
  G 
  are 
  very 
  weak, 
  often 
  entirely 
  invisible 
  ; 
  5 
  and 
  6 
  at 
  equal 
  distances 
  

  

  * 
  A 
  criticism 
  of 
  this 
  view 
  is 
  published 
  in 
  the 
  following 
  chapter 
  i 
  /vs.' 
  td, 
  p. 
  L23). 
  

  

  