﻿RELATION 
  OF 
  HEAT 
  AND 
  DRYNESS 
  TO 
  THE 
  LOCUST. 
  115 
  

  

  1864 
  and 
  1S66 
  being 
  favorable 
  or 
  unfavorable 
  to 
  the 
  increase 
  and 
  spread 
  

   of 
  the 
  locust? 
  

  

  First. 
  That 
  1864, 
  as 
  regards 
  heat 
  and 
  dryness, 
  was 
  unusually 
  favorable 
  

   for 
  their 
  development, 
  and 
  that 
  the 
  decrease 
  in 
  the 
  rainfall 
  the 
  two 
  

   immediately 
  preceding 
  years, 
  rendered 
  the 
  conditions 
  still 
  more 
  favora- 
  

   ble 
  than 
  they 
  would 
  otherwise 
  have 
  been. 
  

  

  • 
  Secondly. 
  That 
  in 
  1866 
  all 
  these 
  conditions 
  were 
  reversed, 
  the 
  rain- 
  

   fall 
  was 
  considerably 
  in 
  excess 
  of 
  the 
  average 
  amount, 
  the 
  season 
  through- 
  

   out 
  the 
  entire 
  Northwest 
  was 
  somewhat 
  colder 
  than 
  in 
  1864, 
  and 
  the 
  pre- 
  

   ceding 
  year 
  presented 
  these 
  adverse 
  conditions 
  to 
  an 
  equal 
  if 
  not 
  greater 
  

   extent. 
  

  

  If 
  it 
  be 
  true, 
  as 
  heretofore 
  stated, 
  that 
  unusual 
  heat 
  and 
  dryness 
  are 
  

   both 
  necessary 
  to 
  the 
  excessive 
  development 
  and 
  spread 
  of 
  locusts, 
  how 
  

   are 
  we 
  to 
  explain 
  the 
  apparent 
  contradiction 
  of 
  this 
  theory 
  shown 
  by 
  the 
  

   data 
  presented 
  ? 
  

  

  So 
  far 
  as 
  the 
  data 
  given 
  relate 
  to 
  1864, 
  the 
  facts 
  accord 
  with 
  the 
  theory, 
  

   the 
  only 
  cause 
  for 
  surprise 
  being 
  that 
  the 
  invasion 
  of 
  the 
  temporary 
  re- 
  

   gion 
  was 
  not 
  more 
  general. 
  The 
  difficulty 
  is 
  to 
  explain 
  how 
  those 
  relat- 
  

   ing 
  to 
  1866 
  can 
  be 
  made 
  to 
  accord 
  with 
  it. 
  That 
  the 
  locusts 
  did 
  invade 
  

   Kansas, 
  Nebraska, 
  Missouri, 
  and 
  a 
  part 
  of 
  Texas 
  this 
  year 
  in 
  large 
  

   numbers 
  is 
  a 
  fact 
  that 
  cannot 
  be 
  disputed, 
  and 
  that 
  large 
  swarms 
  ap- 
  

   peared 
  in 
  Montana 
  is 
  also 
  true 
  ; 
  that 
  the 
  season 
  throughout 
  the 
  entire 
  

   West 
  was 
  generally 
  of 
  a 
  slightly 
  lower 
  temperature 
  and 
  considerably 
  

   more 
  humid 
  than 
  the 
  average 
  is 
  clearly 
  shown 
  by 
  the 
  meteorological 
  

   data 
  given. 
  

  

  Shall 
  we 
  contend 
  that 
  meteorological 
  records 
  do 
  not 
  always 
  correctly 
  

   indicate 
  the 
  general 
  character 
  of 
  the 
  season 
  ? 
  This 
  would 
  be 
  virtually 
  

   saying 
  that 
  they 
  are 
  of 
  no 
  practical 
  value, 
  a 
  proposition 
  we 
  are 
  unwilling 
  

   to 
  assume. 
  Shall 
  we 
  abandon 
  a 
  theory 
  in 
  reference 
  to 
  the 
  increase 
  of 
  

   insect 
  life 
  which 
  accords 
  with 
  the 
  experience 
  of 
  a 
  thousand 
  years, 
  and 
  

   which 
  no 
  one 
  has 
  ever 
  ventured 
  to 
  dispute 
  ? 
  By 
  no 
  means. 
  Whether 
  

   able 
  to 
  explain 
  this 
  apparent 
  contradiction 
  or 
  not 
  we 
  are 
  not 
  prepared 
  

   to 
  abandon 
  either 
  of 
  these 
  views. 
  

  

  Before 
  attempting 
  an 
  explanation 
  we 
  will 
  present 
  fuller 
  records 
  of 
  the 
  

   seasons 
  named 
  as 
  given 
  in 
  the 
  annual 
  reports 
  of 
  the 
  Agricultural 
  De- 
  

   partment, 
  and 
  also 
  bring 
  forward 
  the 
  meteorological 
  data 
  relating 
  to 
  

   the 
  great 
  invasions 
  of 
  1874 
  and 
  1876. 
  

  

  Table 
  III 
  shows 
  the 
  monthly 
  means 
  of 
  rainfall 
  by 
  States, 
  being 
  the 
  

   averages 
  of 
  all 
  the 
  stations 
  in 
  a 
  State. 
  It 
  is 
  from 
  the 
  records 
  in 
  the 
  re- 
  

   ports 
  of 
  the 
  Agricultural 
  Department. 
  

  

  