﻿136 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  firm 
  in 
  a 
  marked 
  or 
  distinct 
  manner 
  the 
  theory 
  that 
  heat 
  and 
  dryness 
  

   are 
  absolutely 
  necessary 
  to 
  an 
  excessive 
  development 
  of 
  locusts. 
  But 
  

   we 
  think 
  the 
  investigation 
  is 
  not 
  without 
  profit, 
  first, 
  because 
  it 
  shows 
  

   that 
  a 
  longer 
  series 
  of 
  years 
  is 
  necessary 
  to 
  determine 
  satisfactorily 
  the 
  

   relation 
  between 
  meteorological 
  conditions 
  and 
  the 
  locust 
  development 
  ; 
  

   second, 
  because 
  it 
  shows 
  that 
  annual 
  and 
  monthly 
  means, 
  so 
  far 
  as 
  tem- 
  

   perature 
  is 
  concerned, 
  are 
  of 
  but 
  little 
  value 
  in 
  the 
  solution 
  of 
  this 
  

   question; 
  third, 
  because 
  it 
  indicates 
  the 
  necessity 
  of 
  paying 
  more 
  atten- 
  

   tion 
  to 
  the 
  temperature 
  in 
  winter, 
  in 
  reference 
  to 
  this 
  question, 
  than 
  we 
  

   have 
  been 
  disposed 
  to 
  allow; 
  fourth, 
  because 
  it 
  presents 
  some 
  facts 
  

   which 
  indicate 
  the 
  necessity 
  of 
  somewhat 
  modifying 
  the 
  theory 
  advanced 
  

   in 
  our 
  First 
  Eeport, 
  and 
  maintained 
  in 
  the 
  previous 
  part 
  of 
  this 
  chapter. 
  

   We 
  have 
  assumed 
  in 
  our 
  First 
  Eeport, 
  as 
  well 
  as 
  the 
  present, 
  that 
  as 
  a 
  

   very 
  general 
  rule 
  the 
  locust 
  swarms 
  that 
  invade 
  Nebraska, 
  Iowa, 
  and 
  

   Kansas 
  come 
  directly 
  from 
  their 
  native 
  breeding-grounds 
  in 
  British 
  

   America, 
  Montana, 
  and 
  Western 
  Dakota. 
  Now, 
  several 
  facts 
  presented 
  

   by 
  the 
  meteorological 
  data 
  agree 
  better 
  with 
  the 
  idea 
  that 
  two 
  seasons 
  

   at 
  least 
  are 
  required 
  for 
  this 
  purpose 
  ; 
  that 
  is, 
  that 
  those 
  developed 
  by 
  

   a 
  favorable 
  season 
  in 
  these 
  northern 
  regions 
  migrate 
  that 
  season 
  to 
  

   Southern 
  Dakota 
  and 
  Northern 
  Nebraska, 
  and, 
  if 
  the 
  next 
  season 
  is 
  

   favorable 
  in 
  this 
  region, 
  move 
  farther 
  south 
  in 
  increased 
  numbers; 
  if 
  

   the 
  season 
  is 
  unfavorable 
  they 
  proceed 
  no 
  farther, 
  or 
  in 
  very 
  diminished 
  

   numbers. 
  The 
  temperature 
  and 
  rainfall 
  in 
  1862-'63, 
  and 
  1872-'73, 
  

   appear 
  to 
  accord 
  better 
  with 
  this 
  theory 
  than 
  the 
  other. 
  

  

  Be 
  this 
  as 
  it 
  may, 
  we 
  have 
  given 
  the 
  facts 
  as 
  we 
  find 
  them, 
  that 
  those 
  

   who 
  desire 
  to 
  investigate 
  the 
  subject 
  may 
  have 
  the 
  data 
  at 
  hand 
  prop- 
  

   erly 
  arranged 
  so 
  as 
  to 
  show 
  their 
  bearing 
  upon 
  the 
  question. 
  We 
  confess 
  

   our 
  disappointment 
  in 
  the 
  result 
  of 
  our 
  attempt 
  to 
  prove 
  a 
  theory 
  so 
  

   long 
  maintained, 
  and 
  so 
  universally 
  believed 
  ; 
  but, 
  as 
  before 
  stated, 
  we 
  

   are 
  unwilling 
  to 
  abandon 
  it, 
  notwithstanding 
  the 
  meteorological 
  records 
  

   fail 
  to 
  confirm 
  it 
  in 
  the 
  marked 
  manner 
  we 
  expected, 
  for 
  personal 
  expe- 
  

   rience 
  and 
  observation 
  have 
  too 
  often 
  confirmed 
  it. 
  

  

  There 
  is 
  still 
  another 
  way 
  in 
  which 
  the 
  relation 
  of 
  tempera! 
  ure 
  to 
  the 
  

   development 
  of 
  the 
  locusts 
  may 
  be 
  viewed 
  which 
  does 
  not 
  appear 
  to 
  

   have 
  been 
  brought 
  forward 
  until 
  touched 
  upon 
  in 
  our 
  First 
  Eeport. 
  

  

  Professor 
  Cleveland 
  Abbe, 
  of 
  the 
  Signal 
  Service 
  Bureau, 
  has 
  suggested 
  

   the 
  idea 
  that 
  the 
  development 
  of 
  the 
  eggs 
  may 
  depend 
  upon 
  the 
  sum 
  of 
  

   the 
  heat 
  rather 
  than 
  the 
  degree 
  ; 
  that 
  is 
  to 
  say, 
  the 
  number 
  of 
  hours 
  they 
  

   are 
  subject 
  to 
  heat 
  above 
  a 
  certain 
  degree. 
  This 
  opinion 
  impressed 
  it- 
  

   self 
  very 
  favorably 
  upon 
  our 
  minds, 
  and 
  the 
  ingenious 
  method 
  adopted 
  

   by 
  the 
  Professor 
  to 
  demonstrante 
  it, 
  as 
  given 
  in 
  our 
  First 
  Eeport 
  206 
  

   agreed 
  so 
  well 
  with 
  the 
  facts 
  that 
  we 
  were 
  disposed 
  to 
  accept 
  it 
  as 
  the 
  

   true 
  key 
  to 
  the 
  relation 
  between 
  temperature 
  and 
  locust 
  development. 
  

  

  Without 
  at 
  present 
  deciding 
  as 
  to 
  its 
  value 
  we 
  must 
  confess 
  that 
  a 
  more 
  

   thorough 
  examination 
  of 
  it 
  has 
  tended 
  to 
  render 
  us 
  somewhat 
  skeptical 
  as 
  

   to 
  the 
  value 
  of 
  the 
  theory 
  when 
  applied 
  to 
  the 
  data 
  in 
  solving 
  the 
  prob- 
  

  

  »' 
  6 
  Pages 
  425-4152. 
  

  

  