﻿ORIGIN 
  OF 
  THE 
  WINGS 
  OF 
  INSECTS. 
  269 
  

  

  Dotumj 
  we 
  have 
  also 
  observed 
  this 
  to 
  be 
  most 
  probably 
  tlie 
  case 
  in 
  tlie 
  

   Lepidoptera, 
  from 
  observations 
  on 
  a 
  Tortrix 
  in 
  dil'ferent 
  stages 
  of 
  meta- 
  

   morphosis/'^^ 
  It 
  is 
  also 
  the 
  case 
  with 
  the 
  Hymenoptera, 
  as 
  wo 
  have 
  

   observed 
  in 
  bees 
  and 
  wasps; 
  '^^ 
  and 
  in 
  these 
  forms, 
  and 
  probably 
  all 
  Hy- 
  

   menoptera, 
  the 
  wings 
  are 
  outgrowths 
  of 
  the 
  scutal 
  region 
  of 
  the 
  notum. 
  

  

  With 
  these 
  facts 
  before 
  us 
  we 
  may 
  speculate 
  as 
  to 
  the 
  probable 
  origin 
  

   of 
  the 
  wings 
  of 
  insects. 
  The 
  views 
  more 
  generally 
  proposed 
  are 
  those 
  

   of 
  Gegenbaur, 
  also 
  adoi)ted 
  by 
  Lubbock 
  ^^^ 
  and 
  originally 
  by 
  myself. 
  ^'^^ 
  

   According 
  to 
  Gegenbaur: 
  ^^ 
  

  

  The 
  wings 
  must 
  be 
  regarded 
  as 
  homologous 
  with 
  the 
  lamellar 
  tracheal 
  gills, 
  for 
  

   they 
  do 
  not 
  only 
  agree 
  with 
  thorn 
  in 
  origin, 
  but 
  also 
  in 
  their 
  connection 
  with 
  the 
  

   body, 
  and 
  in 
  structure. 
  In 
  being 
  limited 
  to 
  the 
  second 
  and 
  third 
  thoracic 
  segments 
  

   they 
  point 
  to 
  a 
  reduction 
  in 
  the 
  number 
  of 
  the 
  tracheal 
  gills. 
  It 
  is 
  quite 
  clear 
  that 
  

   w^e 
  must 
  suppose 
  that 
  the 
  wings 
  did 
  not 
  arise 
  as 
  such, 
  but 
  were 
  developed 
  from 
  organs 
  

   which 
  had 
  another 
  function, 
  such 
  as 
  the 
  tracheal 
  gills; 
  I 
  mean 
  to 
  say 
  that 
  such 
  a 
  

   supi)osition 
  is 
  necessary, 
  for 
  we 
  cannot 
  imagine 
  that 
  the 
  wings 
  functioned 
  as 
  such 
  in 
  

   the 
  lower 
  stages 
  of 
  their 
  development, 
  and 
  that 
  they 
  could 
  have 
  been 
  d(ivelo[)ed 
  by 
  

   having 
  such 
  a 
  function. 
  

  

  The 
  foregoing 
  statements 
  are, 
  however, 
  inexact. 
  If 
  we 
  examine 
  the 
  

   traclieal 
  gills 
  of 
  the 
  smaller 
  dragon-lly 
  (Agrion), 
  or 
  the 
  May 
  Hies, 
  or 
  

   Sialidai, 
  or 
  Perliche, 
  or 
  Phryganeidfc, 
  we 
  see 
  that 
  tliey 
  are 
  dcveIoi)ed 
  

   in 
  a 
  very 
  arbitrary 
  way, 
  either 
  at 
  the 
  end 
  of 
  tlie 
  abdomen, 
  or 
  on 
  the 
  

   sternum, 
  or 
  from 
  the 
  pleurum; 
  moreover, 
  in 
  structure 
  they 
  invariably 
  

   have 
  but 
  a 
  single 
  trachea, 
  from 
  which 
  minute 
  twigs 
  branch 
  out;'^' 
  in 
  the 
  

   wings 
  there 
  are 
  live 
  or 
  six 
  main 
  trachese 
  (Fig. 
  3), 
  which 
  give 
  rise 
  to 
  the 
  

   veins. 
  Thus, 
  in 
  themselves, 
  irrespective 
  of 
  their 
  x)osition, 
  they 
  are 
  not 
  

   the 
  homologues 
  of 
  the 
  gills. 
  The 
  latter 
  are 
  only 
  developed 
  in 
  the 
  a<]uatic 
  

   representatives 
  of 
  the 
  Neuroptera 
  and 
  Pseudoneuroptera, 
  and 
  are 
  evi- 
  

   dently 
  adaptive, 
  secondary, 
  temporary 
  organs, 
  and 
  are 
  in 
  no 
  sense 
  ances- 
  

   tral, 
  i)rimitive 
  structures 
  from 
  which 
  the 
  wings 
  were 
  developed. 
  There 
  

   is 
  no 
  good 
  reason 
  to 
  suppose 
  that 
  the 
  acjuatic 
  Pseudoneuroptei 
  a 
  or 
  Neu- 
  

   roptera 
  Avere 
  not 
  descendants 
  of 
  terrestrial 
  forms. 
  

  

  To 
  these 
  results 
  we 
  had 
  arrived 
  by 
  a 
  review 
  of 
  the 
  above-mentioned 
  

   facts, 
  before 
  meeting 
  with 
  Fritz 
  Miiller's 
  opinions, 
  derived 
  from 
  a 
  study 
  

   of 
  the 
  development 
  of 
  the 
  wings 
  of 
  Oalotermes. 
  Miillcr'^'^ 
  states 
  that 
  

   " 
  ( 
  I) 
  The 
  wings 
  of 
  insects 
  have 
  not 
  originated 
  from 
  ^ 
  tracheal 
  gills 
  \ 
  The 
  

   wing-shaped 
  continuations 
  of 
  the 
  youngest 
  larva) 
  are 
  indeed 
  the 
  only 
  

   parts 
  in 
  which 
  air 
  tubes 
  are 
  completely 
  wanting, 
  while 
  trachejc 
  are 
  richly 
  

   developed 
  in 
  all 
  other 
  parts 
  of 
  the 
  body. 
  (2) 
  The 
  wings 
  of 
  insects 
  have 
  

  

  ''^Comparo 
  also 
  the 
  work 
  of 
  II. 
  Landois 
  on 
  tLo 
  origin 
  of 
  tlio 
  wings 
  i« 
  Lepidoptera. 
  In 
  tlio 
  rudiment- 
  

   ary 
  minute 
  wings 
  there 
  are 
  at 
  first 
  six 
  tracheal 
  branelies 
  eoriesi)onding 
  to 
  the 
  six 
  jnimary 
  veinsof 
  

   the 
  wing. 
  See 
  Siebold 
  and 
  Kolliker's 
  Zeitschrift, 
  Bd. 
  xxi, 
  PI. 
  xxiii, 
  1871. 
  

  

  »27See 
  our 
  Guide 
  to 
  the 
  Study 
  of 
  InscHitH, 
  p. 
  66, 
  figs. 
  65, 
  66. 
  

  

  128 
  Origin 
  and 
  Metamorphoses 
  of 
  Insects, 
  1874, 
  p. 
  73. 
  

  

  »2'J0ur 
  Common 
  Insects, 
  1873, 
  p. 
  171. 
  

  

  '3'" 
  Elements 
  of 
  Comparative 
  Anatomy, 
  English 
  translation, 
  p. 
  247. 
  

  

  131 
  Compare 
  the 
  observations 
  of 
  Palm^u, 
  Gerstiieker, 
  Vayssi6re 
  and 
  others. 
  

  

  132 
  Beitriige 
  zur 
  Kenntniss 
  der 
  Termiten. 
  Jenai.sche 
  Zeitschrift 
  fUr 
  Naturvvissenchaft, 
  Bd. 
  ix, 
  ITeft 
  2, 
  

   p. 
  253, 
  1875. 
  Compare, 
  however, 
  Palm6n's 
  Zur 
  Morphologic 
  des 
  Traclieensystems, 
  Helsiugfors, 
  1877, 
  

   wherein 
  he 
  opposes 
  Miiller's 
  view 
  aud 
  adopts 
  Geugenbaur'a. 
  Bee 
  p. 
  8, 
  foot 
  note. 
  

  

  