﻿644 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  with 
  some 
  certainty 
  be 
  predicted, 
  and, 
  again, 
  its 
  arrival 
  in 
  Kansas 
  and 
  

   adjoining 
  States 
  be 
  announced 
  with 
  a 
  certain 
  amount 
  of 
  precision, 
  as 
  

   has 
  already 
  been 
  done 
  by 
  Dr. 
  Riley, 
  but 
  we 
  shall 
  be 
  able 
  to 
  foretell 
  the 
  

   course 
  taken 
  in 
  the 
  return 
  flight 
  of 
  their 
  progeny 
  in 
  the 
  succeeding 
  

   year. 
  I 
  will 
  confess 
  that 
  previous 
  to 
  my 
  visit 
  to 
  Kansas 
  and 
  Colorado, 
  

   in 
  1875, 
  I 
  was 
  skeptical 
  as 
  to 
  Dr. 
  Rilev's 
  opinion 
  that 
  there 
  was 
  a 
  gen- 
  

   eral 
  movement 
  in 
  a 
  northwest 
  course 
  of 
  the 
  young 
  of 
  the 
  previous 
  year, 
  

   broods 
  from 
  Missouri 
  and 
  adjoining 
  regions 
  northwestward. 
  The 
  facts 
  

   and 
  resulting 
  theory 
  have 
  already 
  been 
  stated 
  in 
  full 
  by 
  Dr. 
  Riley 
  and 
  

   others. 
  It 
  remains 
  to 
  determine 
  the 
  causes 
  of 
  this 
  return 
  migration, 
  this 
  

   completion 
  of 
  the 
  " 
  migration-cycle," 
  as 
  Professor 
  Dawson 
  terms 
  it. 
  

   It 
  is 
  evident 
  that 
  in 
  this 
  case 
  the 
  desire 
  for 
  food 
  is 
  not 
  the 
  cause, 
  for 
  food 
  

   is 
  many 
  times 
  more 
  abundant 
  in 
  the 
  Mississippi 
  Valley 
  than 
  on 
  the 
  

   plains 
  whither 
  they 
  return. 
  The 
  solution 
  of 
  the 
  problem, 
  I 
  think, 
  must 
  

   be 
  sought 
  in 
  the 
  direction 
  of 
  the 
  prevailing 
  winds 
  during 
  the 
  middle 
  of 
  

   June, 
  tlie 
  time 
  when 
  they 
  become 
  winged. 
  It 
  may 
  be 
  found, 
  aiter 
  a 
  

   series 
  of 
  careful 
  meteorological 
  observations, 
  that 
  the 
  prevailing 
  winds 
  

   at 
  this 
  early 
  season 
  are 
  southerly 
  and 
  southeasterly. 
  It 
  has 
  been 
  shown 
  

   by 
  meteorologists, 
  as 
  I 
  learn 
  from 
  Prof. 
  C. 
  Abbe, 
  that 
  during 
  May 
  and 
  

   June 
  the 
  winds 
  blow 
  inward 
  toward 
  the 
  heart 
  of 
  the 
  continent 
  from 
  the 
  

   Atlantic 
  Ocean 
  and 
  Gulf 
  of 
  Mexico. 
  On 
  application 
  to 
  General 
  A. 
  J. 
  

   Myer, 
  Chief 
  of 
  the 
  Signal-Service 
  of 
  the 
  United 
  States 
  Army, 
  for 
  the 
  

   meteorological 
  data 
  necessary 
  to 
  confirm 
  this 
  hypothesis, 
  I 
  promptly 
  

   received 
  a 
  lull 
  summary 
  of 
  data 
  observed 
  by 
  the 
  otBcers 
  of 
  the 
  Weather 
  

   Signal 
  Bureau, 
  for 
  periods 
  of 
  from 
  two 
  to 
  five 
  (usually 
  the 
  latter) 
  years 
  

   between 
  1871 
  and 
  1876, 
  which 
  show 
  that 
  the 
  prevailing 
  winds 
  in 
  June, 
  

   in 
  Davenport, 
  Dodge 
  City, 
  and 
  Keokuk, 
  Iowa 
  ; 
  Saint 
  Paul 
  and 
  Breck- 
  

   enridge, 
  Minn. 
  5 
  Yankton 
  and 
  Fort 
  Sally, 
  Dak,; 
  Omaha, 
  Leavenworth, 
  

   and 
  Fort 
  Gibson, 
  Ind. 
  T. 
  — 
  all 
  within 
  the 
  locust 
  area 
  — 
  are 
  from 
  thesouth- 
  

   east 
  and 
  south. 
  This 
  fact 
  may 
  be 
  sufficient 
  to 
  account 
  for 
  the 
  prevail- 
  

   ing 
  course 
  of 
  the 
  return 
  migrations 
  of 
  the 
  locust 
  from 
  the 
  eastern 
  limits 
  

   of 
  the 
  locust 
  area. 
  

  

  The 
  accompanying 
  table 
  is 
  taken 
  from 
  a 
  synopsis 
  of 
  the 
  meteorological 
  

   phenomena 
  of 
  the 
  Western 
  States 
  and 
  Territories 
  within 
  the 
  eastern 
  

   limits 
  of 
  the 
  locust 
  area, 
  which 
  is 
  appended 
  to 
  this 
  chapter. 
  It 
  has 
  

   been 
  furnished 
  me 
  by 
  Brig. 
  Gen. 
  A. 
  J. 
  Myer, 
  U. 
  S. 
  A., 
  Chief 
  Signal- 
  

   Officer, 
  Washington, 
  D. 
  C, 
  and 
  my 
  heirty 
  thanks 
  are 
  due 
  him 
  for 
  the 
  

   labor 
  and 
  trouble 
  involved 
  in 
  its 
  preparaiiou. 
  

  

  