﻿4B 
  

  

  For 
  the 
  purpose 
  of 
  getting 
  precise 
  evidence 
  with 
  respect 
  to 
  the 
  

   causes 
  of 
  the 
  natural 
  and 
  normal 
  destruction 
  of 
  chinch-bugs 
  leading 
  

   to 
  the 
  disappearance 
  of 
  an 
  outbreak, 
  I 
  set 
  on 
  foot 
  in 
  1896 
  a 
  consider- 
  

   able 
  series 
  of 
  field 
  observations 
  and 
  laboratory 
  experiments. 
  The 
  

   field 
  observations 
  were 
  to 
  be 
  made 
  at 
  frequent 
  intervals 
  throughout 
  

   the 
  entire 
  season 
  in 
  several 
  localities 
  where 
  the 
  chinch-bug 
  was 
  suf- 
  

   fering 
  diminution 
  of 
  numbers 
  from 
  natural 
  causes, 
  and 
  the 
  laboratory 
  

   experiments 
  were 
  planned 
  to 
  test 
  the 
  precise 
  action 
  of 
  such 
  causes 
  as 
  

   were 
  already 
  known 
  or 
  suspected 
  to 
  ojjerate, 
  as 
  well 
  as 
  any 
  others 
  

   which 
  might 
  be 
  suggested 
  in 
  the 
  course 
  of 
  observations 
  in 
  the 
  field. 
  

  

  The 
  known 
  or 
  supposed 
  natural 
  causes 
  of 
  a 
  considerable 
  destruc- 
  

   tion 
  of 
  chinch-bugs 
  are 
  midsummer 
  heat, 
  exjDosure 
  to 
  winter 
  cold, 
  

   wet 
  weather, 
  scarcitj^ 
  or 
  unsuitable 
  character 
  of 
  food, 
  and 
  contagious 
  

   or 
  epidemic 
  disease. 
  Insect 
  parasites 
  and 
  other 
  animal 
  enemies 
  are 
  

   not 
  liere 
  taken 
  into 
  account, 
  because 
  in 
  all 
  the 
  observations 
  upon 
  

   this 
  insect 
  made 
  during 
  a 
  hundred 
  years, 
  nothing 
  has 
  been 
  seen 
  to 
  

   warrant 
  the 
  supposition 
  that 
  these 
  animal 
  agencies 
  have 
  any 
  effect 
  

   of 
  agricultural 
  importance 
  upon 
  the 
  numbers 
  of 
  chinch-bugs. 
  

  

  An 
  investigation 
  into 
  the 
  causes 
  of 
  these 
  phenomena 
  is 
  really 
  a 
  

   study 
  in 
  the 
  field 
  of 
  entomological 
  (ideology; 
  that 
  is, 
  in 
  the 
  relations 
  

   of 
  insects 
  to 
  nature 
  and 
  the 
  effects 
  upon 
  their 
  economy 
  produced 
  by 
  

   natural 
  agencies. 
  It 
  is 
  a 
  much 
  more 
  extensive 
  and 
  complicated 
  sub- 
  

   ject 
  than 
  would 
  at 
  first 
  appear, 
  as 
  may 
  be 
  seen 
  from 
  the 
  following 
  

   list 
  of 
  subordinate 
  problems 
  requiring 
  solution. 
  

  

  The 
  destructive 
  effect 
  of 
  wet 
  summer 
  weather 
  has 
  been 
  known 
  

   almost 
  from 
  the 
  beginning 
  of 
  knowledge 
  on 
  this 
  subject, 
  but 
  the 
  

   method 
  of 
  its 
  action 
  has 
  never 
  been 
  made 
  out 
  with 
  any 
  precision. 
  

  

  1. 
  Does 
  it 
  destroy 
  chinch-bugs 
  directly 
  or 
  indirectly? 
  If 
  directly, 
  

   does 
  it 
  take 
  equal 
  effect 
  upon 
  bugs 
  of 
  all 
  ages, 
  and 
  how 
  does 
  it 
  affect 
  

   the 
  eggV 
  

  

  2. 
  What 
  kind 
  of 
  rainfall 
  is 
  most 
  destructive; 
  brief 
  but 
  violent 
  

   storms, 
  or 
  slow, 
  soaking, 
  long-continued 
  rain? 
  

  

  o. 
  Does 
  the 
  temperature 
  at 
  the 
  time 
  of 
  the 
  rainfall 
  have 
  anything 
  

   to 
  do 
  with 
  such 
  destructive 
  effect 
  of 
  wet 
  weather? 
  

  

  4. 
  Are 
  the 
  chinch-bugs 
  drowned 
  by 
  rain, 
  or 
  are 
  they 
  merely 
  

   washed 
  from 
  their 
  food, 
  imprisoned 
  in 
  the 
  mud, 
  etc.? 
  

  

  5. 
  Is 
  it 
  possible 
  that 
  they 
  are 
  sometimes 
  simply 
  dispersed 
  and 
  

   scattered 
  by 
  fiooding 
  rains, 
  thus 
  giving 
  a 
  fallacious 
  appearance 
  of 
  

   destruction? 
  

  

  (>. 
  If 
  wet 
  weather 
  acts 
  wholly 
  or 
  in 
  part 
  as 
  an 
  indirect 
  agent, 
  does 
  

   it 
  serve 
  to 
  stimulate 
  or 
  occasion 
  disease, 
  and 
  is 
  such 
  disease 
  con- 
  

   tagious 
  or 
  not? 
  

  

  7. 
  If 
  it 
  promotes 
  the 
  appearance 
  and 
  spread 
  of 
  epidemic 
  or 
  con- 
  

   tagious 
  disease, 
  then 
  what 
  disease 
  does 
  it 
  so 
  promote, 
  and 
  what 
  

   other 
  conditions, 
  if 
  anv. 
  conspire 
  with 
  it 
  to 
  produce 
  or 
  intensify 
  this 
  

   effect? 
  

  

  >>. 
  Does 
  it 
  possibly 
  act, 
  to 
  any 
  important 
  degree, 
  by 
  checking 
  

   th(^ 
  multiplication 
  of 
  chinch-bugs, 
  either 
  by 
  preventing 
  the 
  re- 
  

  

  