﻿394 
  

  

  ANNUAL 
  REPOKT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  ties 
  possessed 
  by 
  wasps 
  and 
  ants 
  are 
  superimposed 
  upon 
  a 
  general 
  

   instinct, 
  either 
  the 
  food-collecting 
  instinct, 
  the 
  home-seeking 
  instinct, 
  

   or 
  some 
  other 
  ; 
  they 
  never 
  lead 
  the 
  insects 
  to 
  the 
  doing 
  of 
  new 
  things 
  

   or 
  to 
  the 
  development 
  of 
  new 
  habits 
  that 
  are 
  not 
  clearly 
  modifications 
  

   of 
  old 
  habits. 
  If 
  we 
  seek 
  to 
  translate 
  this 
  kind 
  of 
  behavior 
  into 
  

  

  terms 
  of 
  nerve 
  structure, 
  

   the 
  easiest 
  solution 
  that 
  

   presents 
  itself 
  is 
  the 
  as- 
  

   sumption 
  that 
  another 
  

   switch 
  has 
  been 
  introduced 
  

   into 
  the 
  nerve 
  circuit, 
  which 
  

   allows 
  a 
  sensory 
  impression 
  

   to 
  modify 
  the 
  current 
  in 
  

   the 
  established 
  arc. 
  Thus 
  

   the 
  food-collecting 
  instinct 
  

   may 
  be 
  made 
  to 
  operate 
  in 
  

   connection 
  with 
  the 
  stimu- 
  

   lus 
  of 
  red 
  or 
  of 
  yellow, 
  or 
  

   in 
  connection 
  with 
  a 
  partic- 
  

   ular 
  odor 
  stimulus. 
  Here, 
  

   therefore, 
  we 
  have 
  a 
  pos- 
  

   sible 
  mechanism 
  of 
  modi- 
  

   fiable 
  behavior, 
  one 
  which 
  

   is 
  not 
  inherited 
  in 
  a 
  set 
  

   form, 
  but 
  which 
  may 
  

   become 
  stabilized 
  in 
  the 
  

   individual 
  and 
  give 
  rise 
  to 
  

   a 
  " 
  habit 
  " 
  after 
  repeatedly 
  

   acting 
  in 
  the 
  same 
  way. 
  It 
  

   is 
  possible 
  that 
  such 
  an 
  ap- 
  

   paratus 
  may 
  involve 
  no 
  

   spark 
  of 
  consciousness; 
  it 
  

   is 
  conceivable 
  that 
  it 
  may 
  

   act 
  as 
  mechanically 
  as 
  

   that 
  of 
  a 
  fixed 
  and 
  in- 
  

   herited 
  reflex 
  or 
  instinct. 
  

   It 
  apparently 
  involves 
  

   " 
  memory 
  " 
  but 
  memory 
  in 
  

   this 
  case 
  may 
  be 
  merely 
  the 
  mechanical 
  facility 
  of 
  repeating 
  what 
  

   has 
  been 
  done 
  before. 
  That 
  the 
  insect 
  distinguishes 
  colors, 
  forms, 
  

   odors, 
  and 
  combinations 
  of 
  things 
  may 
  be 
  explained 
  as 
  automatic 
  

   responses 
  to 
  stimuli 
  having 
  no 
  equivalent 
  in 
  consciousness. 
  Yet, 
  if 
  

   we 
  could 
  invoke 
  awareness, 
  the 
  feat 
  of 
  understanding 
  the 
  insect 
  

   would 
  be 
  greatly 
  simplified 
  for 
  us, 
  accustomed 
  as 
  we 
  are 
  to 
  explaining 
  

   our 
  own 
  similar 
  acts 
  in 
  terms 
  of 
  consciousness. 
  

  

  Fig. 
  2. 
  — 
  The 
  brain 
  and 
  subcesophageal 
  ganglion 
  of 
  

   a 
  grasshopper 
  {Dissosteira 
  Carolina) 
  and 
  their 
  

   nerves, 
  as 
  seen 
  after 
  removal 
  of 
  the 
  facial 
  wall 
  

   of 
  the 
  head 
  

  

  AntNv, 
  antennal 
  nerve 
  ; 
  IBr, 
  fore 
  brain 
  ; 
  2Brj 
  mid 
  

   brain 
  ; 
  SBr, 
  hind 
  brain 
  ; 
  CwGon, 
  circumoesophageal 
  

   connective 
  ; 
  3Com, 
  suboesophageal 
  commissure 
  of 
  the 
  

   hind-brain 
  lobes 
  ; 
  FrOng, 
  frontal 
  ganglion 
  ; 
  FrCon, 
  

   frontal 
  ganglion 
  connective 
  with 
  the 
  brain 
  ; 
  LhNv, 
  

   labial 
  nerve 
  ; 
  LmNv, 
  labral 
  nerve 
  ; 
  MdNv, 
  man- 
  

   dibular 
  nerve 
  ; 
  MxNv, 
  maxillary 
  nerve 
  ; 
  O, 
  simple 
  

   eye, 
  or 
  ocellus 
  ; 
  OpL, 
  optic 
  lobe 
  ; 
  RNv, 
  recurrent 
  

   nerve 
  ; 
  8w0ng, 
  suboesophageal 
  ganglion. 
  

  

  