﻿MIND 
  OF 
  AN 
  INSECT 
  SNODGRASS 
  411 
  

  

  with 
  the 
  egg-laying 
  function, 
  except 
  in 
  so 
  far 
  as 
  the 
  usual 
  bodily 
  

   movements 
  were 
  hampered 
  by 
  the 
  loss 
  of 
  the 
  legs 
  ; 
  the 
  abdomen 
  alone, 
  

   when 
  stimulated 
  by 
  pressure, 
  not 
  only 
  deposited 
  the 
  eggs, 
  but 
  placed 
  

   them 
  in 
  the 
  usual 
  symmetrical 
  order. 
  An 
  abdomen 
  placed 
  on 
  its 
  

   back, 
  though, 
  could 
  not 
  right 
  itself, 
  and 
  in 
  this 
  position 
  could 
  not 
  

   extrude 
  the 
  eggs 
  from 
  the 
  egg 
  duct 
  except 
  when 
  the 
  sensory 
  hairs 
  on 
  

   the 
  tip 
  of 
  the 
  ovipositor 
  were 
  touched. 
  On 
  the 
  slightest 
  stimulation 
  

   of 
  these 
  hairs, 
  however, 
  an 
  egg 
  would 
  be 
  ejected 
  — 
  a 
  most 
  interesting 
  

   observation, 
  showing 
  that 
  a 
  local 
  contact 
  reflex 
  controls 
  the 
  actual 
  

   issuing 
  of 
  the 
  eggs, 
  a 
  reflex 
  that 
  normally 
  would 
  assure 
  the 
  presence 
  

   of 
  a 
  surface 
  to 
  receive 
  the 
  eggs, 
  though 
  making 
  no 
  distinction 
  as 
  to 
  

   its 
  nature. 
  

  

  That 
  the 
  head 
  and 
  the 
  thorax 
  of 
  the 
  moth 
  can 
  both 
  be 
  removed, 
  

   and 
  that 
  the 
  abdomen 
  alone 
  can 
  lay 
  eggs, 
  if 
  properly 
  stimulated, 
  

   make 
  it 
  clear 
  that 
  the 
  nerve 
  centers 
  which 
  operate 
  the 
  specific 
  egg- 
  

   laying 
  reflexes 
  lie 
  within 
  the 
  abdomen. 
  Through 
  successively 
  elim- 
  

   inating 
  the 
  action 
  of 
  the 
  segmental 
  abdominal 
  ganglia 
  by 
  cutting 
  the 
  

   connectives 
  between 
  consecutive 
  ganglia. 
  Miss 
  McCracken 
  found 
  that 
  

   as 
  each 
  ganglion 
  was 
  separated 
  its 
  segment 
  failed 
  to 
  take 
  its 
  part 
  in 
  

   the 
  normal 
  egg-laying 
  movements, 
  but 
  that 
  not 
  until 
  the 
  outgoing 
  

   nerves 
  from 
  the 
  last 
  ganglion 
  of 
  the 
  series 
  were 
  severed 
  did 
  the 
  ovi- 
  

   positor 
  become 
  inactive. 
  

  

  From 
  a 
  human 
  standpoint 
  it 
  seems 
  uncanny 
  that 
  an 
  insect 
  can 
  

   be 
  so 
  nearly 
  an 
  automaton 
  as 
  experiments 
  on 
  the 
  working 
  of 
  its 
  

   nervous 
  apparatus 
  show 
  it 
  to 
  be. 
  The 
  manner 
  of 
  an 
  insect 
  at 
  work 
  

   is 
  enough 
  to 
  make 
  the 
  observer 
  believe 
  it 
  is 
  actuated 
  by 
  an 
  almost 
  

   superhuman 
  intelligence; 
  and 
  yet 
  a 
  mere 
  fragment 
  of 
  it 
  can 
  be 
  in- 
  

   dependent 
  not 
  only 
  of 
  the 
  brain, 
  but 
  of 
  all 
  the 
  rest 
  of 
  the 
  body, 
  if 
  

   only 
  its 
  own 
  ganglionic 
  center 
  and 
  nerves 
  are 
  intact. 
  Furthermore, 
  

   the 
  entire 
  set 
  of 
  reflexes 
  that 
  normally 
  come 
  into 
  play 
  during 
  a 
  com- 
  

   plicated 
  performance, 
  such 
  as 
  that 
  of 
  egg 
  laying, 
  can 
  take 
  place 
  in 
  a 
  

   perfectly 
  ordered 
  way 
  in 
  the 
  absence 
  of 
  the 
  brain 
  and 
  without 
  the 
  

   influence 
  of 
  any 
  single 
  coordinating 
  center. 
  Kopec 
  found 
  that 
  several 
  

   intact 
  ganglia 
  were 
  necessary 
  for 
  the 
  performance 
  of 
  body 
  reflexes 
  

   in 
  the 
  caterpillar 
  of 
  the 
  gjpsj 
  moth, 
  the 
  stimulus 
  being 
  sent 
  from 
  

   one 
  ganglion 
  to 
  another 
  without 
  respect 
  to 
  which 
  was 
  first 
  excited. 
  

   In 
  the 
  moth, 
  he 
  says, 
  there 
  is 
  no 
  special 
  coordination 
  center 
  for 
  

   normal 
  forward 
  progression 
  and 
  for 
  flight, 
  the 
  controlling 
  power 
  for 
  

   both 
  these 
  reflexes 
  being 
  in 
  the 
  thoracic 
  ganglia 
  themselves. 
  

  

  The 
  moth 
  deprived 
  of 
  its 
  brain 
  is 
  impassive 
  and 
  must 
  be 
  arti- 
  

   ficially 
  stimulated 
  to 
  activity; 
  the 
  brain, 
  therefore, 
  appears 
  to 
  fur- 
  

   nish 
  the 
  activating 
  impulse 
  for 
  spontaneous 
  movements. 
  "VMien 
  an 
  

   action 
  is 
  once 
  started, 
  however, 
  its 
  reflexes 
  arising 
  in 
  the 
  ventral 
  

   ganglia 
  proceed 
  in 
  the 
  normal 
  manner, 
  or 
  approximately 
  so. 
  But, 
  

  

  