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  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  I^europtera. 
  The 
  Lepidoptera 
  probably 
  originated 
  from 
  the 
  same 
  group 
  

   from 
  which 
  the 
  Panorpidse 
  and 
  Trichoptera 
  branched 
  off, 
  and 
  we 
  agree 
  

   with 
  the 
  opinion 
  of 
  H. 
  MtLller/^'^ 
  who 
  maintains 
  that 
  the 
  Lepidoptera 
  

   and 
  Trichoptera 
  ''proceed 
  from 
  a 
  common 
  stock," 
  though 
  we 
  should 
  silp- 
  

   pose 
  that 
  the 
  Panorpidse 
  in 
  their 
  larval 
  stage 
  represented 
  forms 
  like 
  the 
  

   ancestral 
  caterpillar. 
  

  

  The 
  adult 
  structure 
  and 
  larval 
  forms 
  of 
  the 
  Dipt 
  era 
  show 
  that 
  they 
  

   originated 
  from 
  nearly 
  the 
  same 
  stock 
  as 
  the 
  moths. 
  The 
  most 
  perfectly 
  

   developed 
  Dipterous 
  larvae 
  are 
  those 
  of 
  the 
  Culicidse 
  and 
  Tipulidaej 
  

   these 
  were 
  probably 
  the 
  primitive 
  forms 
  j 
  the 
  other 
  Dipterous 
  larvae, 
  

   notably 
  the 
  larval 
  Muscidae 
  or 
  maggots, 
  are 
  degradational 
  forms, 
  and 
  

   the 
  lower 
  Diptera 
  appear 
  to 
  have 
  been 
  degraded 
  or 
  degenerate 
  forms. 
  

  

  The 
  case 
  is 
  different 
  with 
  the 
  Hymenoj^tera. 
  The 
  saw-fly 
  larvae 
  rep- 
  

   resent 
  apparently 
  the 
  primitive 
  larval 
  form; 
  and 
  from 
  their 
  resem- 
  

   blance 
  to 
  caterpillars 
  and 
  Panorpid 
  larvae, 
  show 
  that 
  the 
  Hymenoptera 
  

   and 
  Lepidoptera 
  may 
  have 
  had 
  a 
  common 
  origin. 
  The 
  footless 
  larvae 
  

   of 
  the 
  parasitic 
  Hymenoptera 
  are 
  correlated 
  with 
  their 
  jjarasitic 
  mode 
  

   of 
  life, 
  and 
  the 
  similar 
  forms 
  of 
  the 
  larval 
  wasps 
  and 
  bees 
  show 
  that 
  

   from 
  disuse 
  their 
  mouth-parts 
  and 
  legs 
  became 
  aborted, 
  and 
  the 
  immo- 
  

   bile 
  larvae 
  became 
  short 
  and 
  thick-bodied. 
  Hence 
  such 
  larvae 
  should 
  

   be 
  regarded 
  as 
  secondary, 
  adaptive 
  larval 
  types. 
  The 
  high 
  degree 
  of 
  

   specialization 
  of 
  the 
  bees' 
  tnouth-parts, 
  their 
  concentrated 
  bodies 
  and 
  

   4-segmented 
  thorax, 
  with 
  other 
  characters, 
  show 
  that 
  they 
  are 
  the 
  

   highest, 
  most 
  specialized 
  and 
  modern 
  of 
  all 
  insects. 
  

  

  Note.— 
  It 
  should 
  be 
  borne 
  in 
  mind 
  that 
  the 
  embryo 
  bee 
  has 
  a 
  pair 
  

   of 
  temi3orary 
  abdominal 
  appendages 
  on 
  each 
  segment 
  (uromere); 
  so 
  

   also 
  has 
  the 
  Lepidopterous, 
  Coleopterous, 
  and 
  Orthopterous 
  embryo, 
  

   which 
  points 
  back 
  to 
  a 
  common, 
  Scolopendrella-like 
  type; 
  this 
  also 
  pos- 
  

   sibly 
  indicating 
  a 
  still 
  earlier, 
  worm-like, 
  Peripatus-like 
  ancestor 
  for 
  

   Myriopoda 
  and 
  Hexapoda 
  at 
  least, 
  if 
  not 
  Arachnida. 
  For 
  previous 
  dis- 
  

   cussions 
  as 
  to 
  the 
  origin 
  of 
  insects 
  the 
  reader 
  is 
  referred 
  to 
  the 
  writings 
  

   of 
  Fritz 
  Miiller, 
  Brauer, 
  Lubbock, 
  and 
  the 
  author. 
  

  

  Order 
  II. 
  DERMATOPTEEA. 
  

   FoRFicuLiD^. 
  Plates 
  XXIII, 
  XXIV. 
  

  

  THE 
  HEAD. 
  

  

  Forficula 
  tceniata 
  Dohrn. 
  (PI. 
  XXIII, 
  figs. 
  1-3). 
  The 
  head 
  is 
  horizon- 
  

   tal 
  in 
  position, 
  broad 
  and 
  flat, 
  squarish, 
  the 
  sides 
  being 
  parallel. 
  There 
  

   is 
  a 
  V-shaped 
  epicranial 
  suture, 
  which 
  is 
  more 
  distinct 
  in 
  the 
  larvae 
  of 
  

   this 
  genus 
  and 
  in 
  Labia. 
  The 
  epicranium 
  is 
  otherwise 
  simple; 
  no 
  ocelli. 
  

   The 
  clypeus 
  is 
  simple, 
  being 
  no 
  wider 
  and 
  not 
  much 
  larger 
  than 
  the 
  lab- 
  

   rum. 
  The 
  genal 
  ridge 
  prominent; 
  a 
  broad 
  gular 
  region. 
  Behind 
  the 
  

  

  iw 
  American 
  Naturalist, 
  v-, 
  July, 
  1871, 
  288. 
  See 
  also 
  the 
  same 
  magazine, 
  Nov., 
  1871, 
  p. 
  707-713. 
  

  

  