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  them, 
  but 
  on 
  approaching 
  these 
  offensive 
  substances 
  the 
  bugs 
  turn 
  

   and 
  run 
  along 
  the 
  ridge 
  in 
  the 
  evident 
  hope 
  of 
  finding 
  a 
  gap 
  through 
  

   which 
  they 
  may 
  pass. 
  

  

  "Coal-tar 
  is 
  the 
  best 
  of 
  the 
  substances 
  named 
  in 
  that 
  it 
  stands 
  on 
  

   the 
  surface 
  better 
  and 
  is 
  not 
  so 
  readily 
  washed 
  away 
  by 
  rains. 
  

   However, 
  crude 
  petroleum 
  and 
  kerosene 
  are 
  very 
  efficient 
  and 
  are 
  

   more 
  generally 
  available 
  than 
  the 
  coal-tar. 
  The 
  coal-tar 
  can 
  be 
  

   easily 
  aj)plied 
  by 
  means 
  of 
  an 
  old 
  tea-kettle, 
  sprinkler, 
  or 
  coff'ee-pot. 
  

   The 
  stream 
  poured 
  upon 
  the 
  ridge 
  need 
  not 
  be 
  more 
  than 
  half 
  an 
  

   inch 
  in 
  diameter, 
  and 
  when 
  of 
  this 
  size 
  the 
  operator 
  should 
  walk 
  

   rather 
  rapidly 
  in 
  applying 
  it. 
  * 
  * 
  * 
  

  

  "It 
  would 
  be 
  well 
  to 
  form 
  the 
  ridge 
  for 
  the 
  barrier 
  a 
  week 
  or 
  two 
  

   before 
  it 
  is 
  needed. 
  (Ridges 
  formed 
  last 
  summer 
  by 
  Mr. 
  Marcy's 
  

   drag 
  were 
  in 
  excellent 
  condition 
  after 
  having 
  withstood 
  the 
  heavy, 
  

   beating 
  rains 
  of 
  July 
  and 
  August.) 
  Then 
  the 
  tar, 
  kerosene, 
  etc., 
  

   may 
  be 
  spread 
  at 
  a 
  moment's 
  notice 
  and 
  the 
  post-holes 
  dug. 
  After 
  

   the 
  barrier 
  is 
  formed, 
  it 
  should 
  be 
  inspected 
  daily 
  and 
  kept 
  in 
  good 
  

   repair. 
  This 
  will 
  not 
  require 
  much 
  time, 
  and 
  should 
  not 
  be 
  omitted. 
  

   Perhaps 
  no 
  other 
  repair 
  will 
  be 
  necessary 
  than 
  the 
  addition 
  of 
  a 
  small 
  

   amount 
  of 
  tar. 
  kerosene, 
  etc. 
  If 
  the 
  small 
  grain 
  has 
  been 
  harvested 
  

   and 
  the 
  bugs 
  are 
  all 
  moving 
  at 
  once 
  into 
  the 
  corn 
  they 
  may 
  be 
  

   trapped 
  and 
  the 
  necessity 
  for 
  vigilance 
  is 
  soon 
  over; 
  but 
  if 
  they 
  are 
  

   coming 
  more 
  slowly 
  from 
  the 
  ripening 
  grain 
  the 
  barriers 
  must 
  be 
  

   kept 
  up 
  a 
  few 
  days 
  longer. 
  

  

  "The 
  results 
  of 
  this 
  method 
  of 
  combating 
  chinch 
  bugs 
  were 
  well 
  

   shown 
  by 
  experiments 
  in 
  the 
  wheat 
  field. 
  The 
  bugs 
  were 
  noticed 
  

   early 
  in 
  this 
  wheat, 
  and 
  just 
  before 
  harvest 
  and 
  before 
  the 
  bugs 
  had 
  

   migrated 
  to 
  the 
  corn, 
  the 
  ridge 
  was 
  thrown 
  up, 
  coal-tar 
  was 
  applied, 
  

   and 
  the 
  post-holes 
  dug. 
  The 
  bugs 
  which 
  collected 
  and 
  died 
  in 
  the 
  

   first 
  few 
  holes 
  were 
  taken 
  out 
  and 
  piled 
  near 
  the 
  holes 
  in 
  great 
  quan- 
  

   tities. 
  Only 
  a 
  few 
  bugs 
  escaped, 
  and 
  no 
  damage 
  was 
  done 
  to 
  the 
  

   corn. 
  

  

  "In 
  another 
  case, 
  the 
  bugs 
  had 
  left 
  the 
  wheat 
  and 
  had 
  advanced 
  

   about 
  fifty 
  rows 
  in 
  the 
  corn, 
  destroying 
  it 
  utterly 
  as 
  they 
  advanced. 
  

   * 
  * 
  * 
  Then 
  the 
  ridge 
  was 
  thrown 
  up, 
  tar 
  was 
  put 
  on, 
  and 
  post- 
  

   holes 
  dug. 
  The 
  result 
  was 
  that 
  the 
  bugs 
  were 
  caught 
  and 
  died 
  in 
  

   the 
  holes, 
  so 
  that 
  the 
  corn 
  suffered 
  no 
  further 
  injury. 
  These 
  two 
  

   instances 
  demonstrate 
  the 
  value 
  of 
  the 
  barrier 
  method 
  described 
  

   above. 
  * 
  *' 
  "■ 
  If 
  the 
  ridge 
  is 
  not 
  formed 
  and 
  the 
  offensive 
  sub- 
  

   stances 
  are 
  simply 
  spread 
  upon 
  the 
  ground, 
  the 
  bugs, 
  when 
  in 
  great 
  

   numbers, 
  crowd 
  each 
  other 
  across 
  the 
  barrier, 
  those 
  in 
  front 
  being 
  

   unwillingly 
  carried 
  forward 
  by 
  those 
  behind; 
  or, 
  if 
  the 
  post-holes 
  are 
  

   omitted, 
  the 
  bugs 
  are 
  not 
  destroyed, 
  and 
  manage 
  finally 
  to 
  struggle 
  

   into 
  the 
  corn 
  field 
  after 
  the 
  barrier 
  has 
  become 
  damaged 
  bj' 
  the 
  

   weather. 
  

  

  "The 
  barrier 
  method 
  has 
  the 
  advantage 
  of 
  not 
  being 
  dependent 
  upon 
  

   a 
  complexity 
  of 
  conditions 
  for 
  its 
  success, 
  and 
  of 
  giving 
  immediate 
  

   results. 
  It 
  has 
  the 
  disadvantage 
  of 
  being 
  only 
  applicable 
  at 
  the 
  very 
  

   short 
  time 
  when 
  the 
  bugs 
  are 
  migrating 
  from 
  one 
  field 
  to 
  another. 
  

   It 
  cannot 
  be 
  used 
  upon 
  bugs 
  already 
  scattered 
  through 
  the 
  small 
  

  

  