﻿8() 
  

  

  bug 
  in 
  the 
  tiold, 
  laboratory 
  experinicuts 
  with 
  uniform 
  temperatures 
  

   were 
  conducted 
  on 
  lots 
  of 
  cliiucb-bngs' 
  eggs 
  obtained 
  in 
  continement 
  

   under 
  conditions 
  such 
  as 
  to 
  insure 
  normal 
  fertilization 
  of 
  the 
  eggs. 
  

   Twenty-tive 
  eggs 
  set 
  aside 
  August 
  12, 
  1^)5, 
  without 
  treatment, 
  and 
  

   kept 
  as 
  a 
  check, 
  all 
  hatched 
  except 
  two 
  which 
  had 
  evidently 
  been 
  

   injured, 
  hatching 
  beginning 
  August 
  17 
  and 
  continuing 
  until 
  

   August 
  22. 
  

  

  Lots 
  of 
  ton 
  eggs 
  each 
  were 
  placed 
  in 
  small 
  covered 
  tin 
  pill-boxes 
  

   (of 
  one-eighth 
  ounce 
  capacity) 
  and 
  placed 
  in 
  a 
  sterilizer 
  at 
  uniform 
  

   temperatures 
  varying 
  from 
  \)IA 
  Fahr. 
  (33 
  Cent.) 
  to 
  186.4" 
  Fahr. 
  

   (58" 
  Cent.) 
  and 
  exposed 
  for 
  periods 
  varying 
  from 
  two 
  hours 
  to 
  six- 
  

   teen 
  and 
  a 
  half 
  hours. 
  After 
  these 
  experimental 
  (Exposures 
  to 
  uni- 
  

   form 
  dry 
  heat 
  the 
  eggs 
  were 
  placed 
  under 
  conditions 
  most 
  favorable 
  

   to 
  their 
  hatching 
  and 
  watched 
  from 
  day 
  to 
  day 
  until 
  they 
  either 
  

   hatched 
  or 
  were 
  evidently 
  spoiled. 
  Of 
  ten 
  lots 
  so 
  treated 
  only 
  three 
  

   hatched, 
  and 
  of 
  these 
  all 
  hatched 
  with 
  the 
  exception 
  of 
  one 
  specimen 
  

   in 
  each 
  of 
  two 
  lots, 
  crushed 
  by 
  accident. 
  The 
  temperature 
  exposures 
  

   thus 
  found 
  to 
  be 
  harmless 
  were 
  fourteen 
  hours' 
  exposure 
  to 
  91.4^ 
  

   Fahr.. 
  six 
  hours" 
  exjiosure 
  to 
  95 
  \ 
  and 
  seventeen 
  hours" 
  exposure 
  to 
  

   109.4 
  \ 
  

  

  The 
  minimum 
  exposure 
  found 
  destructive 
  to 
  the 
  chinch-bug 
  egg 
  

   was 
  two 
  hours 
  at 
  116.8" 
  Fahr.. 
  all 
  the 
  temperatures 
  above 
  this 
  min- 
  

   imum 
  being 
  of 
  course 
  fatal 
  to 
  the 
  egg. 
  The 
  various 
  lots 
  which 
  

   finally 
  hatched 
  were 
  neither 
  notably 
  retarded 
  nor. 
  hastened 
  in 
  de- 
  

   velopment 
  by 
  their 
  treatment. 
  No 
  experiments 
  were 
  made 
  to 
  ascer- 
  

   tain 
  the 
  etfects 
  of 
  high 
  temperatures 
  in 
  moist 
  air 
  upon 
  the 
  chinch- 
  

   bug 
  egg. 
  

  

  Field 
  Temperat 
  lives 
  in 
  Hot 
  Midsunniiev 
  Weather. 
  — 
  Having 
  fre- 
  

   quently 
  observed 
  during 
  field 
  experimental 
  operations 
  the 
  destruction 
  

   of 
  chinch-bugs 
  by 
  direct 
  exposure 
  to 
  the 
  heat 
  of 
  the 
  sun 
  in 
  furrows 
  

   of 
  dry 
  and 
  dusty 
  earth. 
  I 
  directed 
  during 
  the 
  summer 
  of 
  1895 
  some 
  

   observations 
  and 
  experiments 
  intended 
  to 
  determine 
  (1) 
  field 
  tem- 
  

   peratures 
  during 
  the 
  heat 
  of 
  the 
  summer 
  in 
  situations 
  frequented 
  by 
  

   chinch-bugs, 
  and 
  (2) 
  the 
  power 
  of 
  resistance 
  of 
  chinch-bugs 
  of 
  va- 
  

   rious 
  ages 
  to 
  high 
  temperatures, 
  dry 
  and 
  moist 
  * 
  

  

  August 
  IB. 
  1895, 
  a 
  bright 
  summer 
  day 
  in 
  the 
  midst 
  of 
  a 
  long 
  sea- 
  

   of 
  heat 
  and 
  drouth, 
  with 
  a 
  maximum 
  temperature 
  for 
  the 
  day 
  of 
  93"\ 
  

   a 
  minimum 
  of 
  55 
  \ 
  and 
  a 
  mean 
  of 
  76 
  \ 
  it 
  was 
  found 
  at 
  3:30 
  p. 
  m. 
  that 
  

   a 
  thermometer 
  four 
  feet 
  above 
  the 
  ground, 
  in 
  the 
  shade, 
  registered 
  

   92' 
  Fahr.; 
  in 
  the 
  sun, 
  six 
  feet 
  above 
  the 
  surface, 
  98' 
  . 
  At 
  this 
  time 
  

   the 
  temperature 
  of 
  the 
  surface 
  layers 
  of 
  the 
  soil, 
  as 
  tested 
  by 
  a 
  

   thermometer 
  laid 
  horizontally 
  upon 
  the 
  surface 
  and 
  barely 
  covered 
  

   with 
  dirt, 
  was 
  128\ 
  Similarly 
  placed 
  in 
  the 
  shade, 
  the 
  temperature 
  

   reading 
  was 
  80". 
  Tnder 
  a 
  clod 
  three 
  inches 
  in 
  diameter, 
  exposed 
  to 
  

   the 
  sun 
  in 
  a 
  corn 
  field, 
  the 
  temperature 
  was 
  113; 
  on 
  the 
  surface 
  of 
  

   the 
  ground 
  in 
  the 
  midst 
  of 
  green 
  vegetation, 
  in 
  the 
  sun. 
  103"; 
  on 
  the 
  

   surface 
  under 
  dead 
  grass, 
  in 
  the 
  sun. 
  94"; 
  in 
  corn, 
  behind 
  the 
  sheath 
  

   of 
  a 
  leaf, 
  three 
  and 
  one 
  half 
  feet 
  above 
  the 
  ground. 
  h9 
  , 
  and 
  two 
  feet 
  

  

  'EiirliiT 
  data 
  on 
  both 
  tliese 
  points 
  may 
  be 
  found 
  in 
  my 
  last 
  entomological 
  Report, 
  pp. 
  S-12. 
  

  

  