﻿No. 
  9. 
  The 
  eight 
  remaining 
  alive 
  just 
  able 
  to 
  crawl. 
  Threeof 
  them 
  

   died 
  afterwards. 
  

  

  No. 
  36. 
  One 
  of 
  those 
  living 
  was 
  an 
  adult, 
  three 
  were 
  pupae, 
  and 
  

   one 
  was 
  of 
  the 
  second 
  molt. 
  

  

  37. 
  The 
  living 
  were 
  adults, 
  pupae, 
  and 
  bugs 
  of 
  the 
  second 
  molt. 
  

  

  The 
  data 
  of 
  the 
  foregoing 
  tables 
  are 
  not 
  everywhere 
  self-consistent, 
  

   the 
  results 
  of 
  some 
  experiments 
  being 
  out 
  of 
  agreement 
  with 
  those 
  of 
  

   other 
  experiments 
  professedly 
  identical, 
  but 
  these 
  minor 
  inconsisten- 
  

   cies 
  are 
  not 
  uncommon 
  in 
  biological 
  experimentation, 
  and 
  are 
  some- 
  

   times 
  unavoidable. 
  In 
  our 
  case 
  they 
  are 
  probably 
  usually 
  due 
  to 
  the 
  

   different 
  history 
  and 
  previous 
  treatment 
  of 
  lots 
  of 
  specimens 
  used 
  in 
  

   the 
  experiments. 
  With 
  the 
  exception 
  of 
  Nos. 
  1 
  and 
  2 
  the 
  specimens 
  

   were 
  placed 
  in 
  small 
  covered 
  tin 
  pill-boxes 
  of 
  one-eighth 
  ounce 
  

   capacity, 
  instead 
  of 
  being 
  enclosed, 
  as 
  in 
  all 
  the 
  other 
  experiments, 
  in 
  

   glass 
  Petri 
  dishes 
  three 
  inches 
  in 
  diameter 
  and 
  an 
  inch 
  in 
  depth. 
  

   The 
  difference 
  in 
  result 
  due 
  to 
  this 
  difference 
  in 
  management 
  is 
  

   shown 
  by 
  a 
  comparison 
  of 
  Experiments 
  Nos. 
  2 
  and 
  9, 
  in 
  the 
  first 
  of 
  

   which 
  half 
  an 
  hour's 
  exposure 
  to 
  a 
  moist 
  heat 
  of 
  122° 
  killed 
  all 
  the 
  

   specimens, 
  while 
  in 
  the 
  second 
  an 
  equal 
  exposure 
  to 
  a 
  temperature 
  

   of 
  130° 
  to 
  133° 
  was 
  fatal 
  to 
  only 
  two 
  thirds 
  of 
  those 
  subjected 
  to 
  it. 
  

   Nos. 
  1 
  and 
  2, 
  for 
  this 
  reason, 
  should 
  be 
  rejected. 
  

  

  The 
  lowest 
  temperature 
  recorded 
  by 
  which 
  chinch-bugs 
  may 
  be 
  

   killed 
  in 
  moist 
  air 
  is 
  116.6°, 
  and 
  in 
  this 
  case 
  all 
  died 
  on 
  twenty 
  

   hours' 
  exposure 
  (No. 
  42) 
  . 
  A 
  temperature 
  of 
  118.4° 
  of 
  moist 
  heat 
  

   was 
  completely 
  fatal 
  after 
  six 
  hours' 
  exposure, 
  and 
  the 
  greater 
  part 
  

   of 
  those 
  subjected 
  to 
  a 
  temperature 
  varying 
  from 
  120° 
  to 
  123° 
  died 
  

   after 
  two 
  hours' 
  exposure 
  (No. 
  36). 
  On 
  the 
  other 
  hand, 
  none 
  were 
  

   killed 
  by 
  one 
  hour's 
  endurance 
  of 
  120.2°; 
  about 
  twenty-five 
  per 
  cent, 
  

   were 
  able 
  to 
  endure 
  from 
  130° 
  to 
  133° 
  for 
  at 
  least 
  half 
  an 
  hour 
  (No. 
  

   9) 
  ; 
  and 
  about 
  twenty 
  per 
  cent, 
  survived 
  after 
  two 
  and 
  a 
  half 
  hours' 
  

   exposure 
  to 
  a 
  temperature 
  of 
  120° 
  to 
  123°. 
  The 
  lowest 
  temperature 
  

   and 
  the 
  shortest 
  periods 
  found 
  completely 
  fatal 
  in 
  dry 
  air 
  are 
  116.6° 
  

   for 
  twenty 
  hours, 
  118.4° 
  for 
  six 
  hours, 
  120° 
  for 
  three 
  hours, 
  125° 
  for 
  

   one 
  hour, 
  and 
  120° 
  to 
  132° 
  for 
  half 
  an 
  hour. 
  

  

  A 
  comparison 
  of 
  these 
  conclusions 
  with 
  data 
  already 
  published, 
  

   based 
  on 
  field 
  observations 
  (see 
  my 
  Eighth 
  Report, 
  p. 
  10) 
  , 
  leaves 
  an. 
  

   unexplained 
  discrepancy. 
  In 
  Experiment 
  No. 
  3, 
  there 
  reported, 
  chinch- 
  

   bugs 
  began 
  to 
  die 
  in 
  the 
  open 
  field 
  when 
  exposed 
  to 
  the 
  sun 
  when 
  

   the 
  surface 
  dirt 
  had 
  reached 
  a 
  temperature 
  of 
  108°, 
  and 
  in 
  twenty 
  

   minutes 
  at 
  122° 
  of 
  surface 
  temperature 
  most 
  of 
  those 
  exposed 
  to 
  it 
  

   were 
  dead 
  (see 
  page 
  9, 
  Report 
  cited) 
  . 
  A 
  similar 
  observation 
  is 
  re- 
  

   corded 
  on 
  page 
  38 
  of 
  the 
  present 
  Report, 
  according 
  to 
  which 
  110° 
  of 
  

   heat 
  in 
  the 
  surface 
  of 
  layer 
  dust 
  was^ 
  found 
  rapidly 
  fatal 
  to 
  young 
  

   bugs. 
  

  

  The 
  greater 
  efficiency 
  of 
  dry 
  heat 
  may 
  be 
  seen 
  by 
  contrasting 
  Ex- 
  

   periments 
  11 
  and 
  12, 
  13 
  and 
  14 
  on 
  the 
  one 
  hand 
  with 
  15 
  on 
  the 
  other, 
  

   No. 
  18 
  with 
  19, 
  26 
  with 
  27, 
  28 
  with 
  29, 
  and 
  30 
  with 
  31. 
  

  

  Temperature 
  Ex^jerimenis 
  with 
  Chinch-bugs^ 
  ^[/QS- 
  — 
  l^o 
  ascer- 
  

   tain 
  the 
  temperature 
  exposures 
  destructive 
  of 
  the 
  egg 
  of 
  the 
  chinoh- 
  

  

  