﻿PROCEEDINGS 
  OF 
  THE 
  TOURTH 
  ENTO^M 
  ©LOGICAL 
  MEETING 
  369 
  

  

  lines 
  of 
  its 
  career, 
  the 
  crucial 
  acts 
  of 
  its 
  life, 
  are 
  mostly 
  gone 
  through 
  

   in 
  a 
  blind 
  and 
  unreasoning 
  way, 
  and 
  may 
  be 
  without 
  serious 
  practical 
  

   error 
  regarded 
  as 
  more 
  or 
  less 
  simple 
  " 
  reflexes 
  " 
  executed 
  in 
  response 
  

   to 
  a 
  certain 
  stimulus 
  or 
  set 
  of 
  conditions. 
  They 
  are 
  points 
  in 
  the 
  insect's 
  

   life 
  where 
  action 
  and 
  environment 
  are 
  most 
  closely 
  knit 
  together, 
  and 
  

   in 
  at 
  any 
  rate 
  most 
  species 
  these 
  points 
  will 
  include 
  all 
  those 
  which 
  

   in 
  any 
  real 
  and 
  permanent 
  way 
  affect 
  the 
  welfare 
  of 
  the 
  individual 
  

   and 
  the 
  race. 
  Insects 
  with 
  specialized 
  habits 
  may 
  be 
  regarded 
  as 
  

   tuned 
  to 
  respond 
  blindly 
  to 
  a 
  few 
  particular 
  stimuli 
  or 
  sets 
  of 
  conditions 
  

   perceived 
  by 
  a 
  specialized 
  receptivity 
  of 
  one 
  or 
  more 
  of 
  their 
  senses, 
  

   and 
  these 
  stimuli, 
  which 
  need 
  not 
  necessarily 
  be 
  at 
  all 
  complex, 
  should 
  

  

  be 
  discoverable 
  Once 
  we 
  have 
  ■ 
  discovered 
  the 
  stimuli 
  which 
  

  

  control 
  the 
  life 
  of 
  the 
  mosquito, 
  we 
  hold 
  the 
  key 
  of 
  the 
  position, 
  and 
  

   it 
  will 
  be 
  strange 
  if 
  we 
  cannot 
  use 
  our 
  advantage 
  to 
  the 
  insect's 
  undoing. 
  

   It 
  is 
  no 
  intelligent 
  foe 
  we 
  have 
  to 
  fight, 
  but 
  a 
  mere 
  battalion 
  of 
  somnam- 
  

   bulists." 
  

  

  To 
  discover 
  these 
  stimuli 
  it 
  is 
  necessary 
  to 
  have 
  some 
  idea 
  of 
  the 
  way 
  

   in 
  which 
  these 
  stimuli 
  are 
  to 
  be 
  perceived, 
  that 
  is 
  to 
  say, 
  to 
  know 
  the 
  

   nature 
  of 
  the 
  sense 
  or 
  senses 
  on 
  which 
  the 
  insect 
  relies 
  for 
  guidance 
  in 
  

   performing 
  some 
  given 
  act, 
  such, 
  for 
  example, 
  as 
  oviposition 
  or 
  feeding. 
  

   To 
  do 
  this 
  it 
  is 
  necessary 
  to 
  put 
  some 
  of 
  the 
  sense 
  organs 
  out 
  of 
  action, 
  

   by 
  amputation 
  or 
  othervnse, 
  and 
  note 
  how 
  the 
  loss 
  affects 
  the 
  behaviour 
  

   of 
  the 
  insect. 
  Such 
  operations 
  can 
  be 
  most 
  easily 
  perform.ed 
  on 
  the 
  

   eyes, 
  ocelli, 
  antennae 
  and 
  such 
  tactile 
  or 
  other 
  sense 
  organs 
  as 
  reside 
  

   in 
  the 
  extremities. 
  Experiment 
  has 
  already 
  shown 
  that 
  the 
  actions 
  

   of 
  many 
  insects 
  are 
  directed 
  far 
  more 
  by 
  the 
  antennal 
  sense 
  of 
  smell 
  

   or 
  " 
  smell-taste," 
  than 
  that 
  of 
  sight. 
  Moreover, 
  the 
  sense 
  of 
  smell 
  

   is 
  for 
  certain 
  substances 
  remarkably 
  acute, 
  and 
  the 
  influence 
  of 
  parti- 
  

   cular 
  smells 
  on 
  the 
  actions 
  of 
  the 
  insect 
  at 
  certain 
  periods 
  of 
  its 
  life 
  

   may 
  be 
  of 
  so 
  strong 
  and 
  constant 
  a 
  nature 
  as 
  to 
  make 
  it 
  difficult 
  to 
  avoid 
  

   the 
  conclusion 
  that 
  by 
  playing 
  upon 
  the 
  olfactory 
  susceptibilities 
  of 
  

   insects 
  we 
  may 
  obtain 
  over 
  their 
  movements 
  and 
  actions 
  a 
  very 
  large 
  

   measure 
  of 
  control. 
  

  

  Take 
  the 
  probably 
  common 
  case, 
  for 
  example, 
  of 
  a 
  species 
  in 
  which 
  

   the 
  males 
  are 
  guided 
  to 
  the 
  females 
  (or 
  vice 
  versa) 
  by 
  a 
  sexual 
  odour, 
  

   while 
  the 
  females 
  lay 
  their 
  eggs 
  in 
  response 
  to 
  a 
  particular 
  smell 
  or 
  

   simple 
  combination 
  of 
  smells. 
  Assuming 
  these 
  smells 
  to 
  be 
  discovered, 
  

   we 
  should 
  have 
  the 
  means 
  of 
  controlling 
  the 
  members 
  of 
  that 
  species 
  

   to 
  an 
  extent 
  probably 
  unequalled 
  by 
  any 
  other 
  method. 
  In 
  this 
  example 
  

   we 
  have 
  supposed 
  only 
  one 
  sense 
  to 
  be 
  involved, 
  and 
  in 
  many 
  insects 
  

   the 
  sense 
  of 
  smell 
  is 
  undoubtedly 
  the 
  most 
  important. 
  At 
  the 
  same 
  

   time 
  there 
  is 
  equally 
  little 
  doubt 
  that 
  the 
  perception 
  of 
  moisture 
  and 
  

  

  