﻿100 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  Yersin 
  m 
  gives 
  40 
  or 
  50 
  feet 
  as 
  the 
  height. 
  Kohl 
  200 
  says 
  that 
  in 
  fine 
  

   warm 
  weather 
  the 
  locusts 
  fly 
  very 
  high, 
  from 
  20 
  to 
  30 
  fathoms 
  (150 
  to- 
  

   200 
  feet) 
  ; 
  but 
  in 
  cloudy 
  weather 
  they 
  fly 
  much 
  lower, 
  scarcely 
  a 
  fathom 
  

   high. 
  These 
  statements 
  evidently 
  apply 
  only 
  to 
  short 
  local 
  flights^ 
  

   as 
  these 
  writers 
  were 
  fully 
  aware 
  of 
  the 
  fact 
  that 
  P. 
  migratorius, 
  of 
  

   which 
  they 
  are 
  speaking, 
  frequently 
  passes 
  over 
  extensive 
  mountain 
  

   ranges 
  covered 
  with 
  forests, 
  which 
  would 
  of 
  necessity 
  require 
  a 
  greater 
  

   elevation 
  than 
  that 
  given. 
  Bowles 
  201 
  says 
  that 
  C. 
  italicus, 
  when 
  start- 
  

   ing 
  on 
  a 
  flight 
  in 
  swarms, 
  gradually 
  rises 
  to 
  the 
  height 
  of 
  400 
  or 
  500- 
  

   feet.. 
  

  

  As 
  the 
  elevation 
  given 
  by 
  these 
  writers 
  is 
  so 
  far 
  below 
  that 
  at 
  which 
  

   swarms 
  of 
  C. 
  spretus 
  attain 
  in 
  a 
  general 
  movement, 
  we 
  presume 
  no 
  at- 
  

   tempt 
  was 
  made 
  to 
  ascertain 
  the 
  greatest 
  height 
  reached. 
  

  

  7. 
  OTHER 
  FACTS 
  IN 
  REFERENCE 
  TO 
  FLIGHT. 
  

  

  As 
  stated 
  in 
  our 
  former 
  report, 
  flights 
  in 
  different 
  directions 
  at 
  the 
  

   same 
  time 
  and 
  place 
  are 
  not 
  of 
  frequent 
  occurrence, 
  but 
  have 
  been 
  oc- 
  

   casionally 
  observed 
  in 
  the 
  case 
  of 
  C. 
  spretus. 
  These 
  are 
  always 
  one 
  above 
  

   the 
  other 
  and 
  in 
  different 
  air 
  currents, 
  sometimes 
  in 
  directly 
  opposite 
  

   directions, 
  sometimes 
  one 
  column 
  crossing 
  the 
  other 
  obliquely. 
  The 
  in- 
  

   stances 
  mentioned 
  in 
  our 
  first 
  report 
  are 
  the 
  only 
  ones 
  of 
  which 
  we 
  have 
  

   any 
  knowledge. 
  

  

  Whether 
  a 
  swarm 
  ever, 
  by 
  ascending 
  or 
  descending 
  into 
  a 
  different 
  

   current 
  of 
  air, 
  changes 
  its 
  course 
  without 
  alighting, 
  is 
  a 
  question 
  as 
  yet 
  

   undecided. 
  From 
  their 
  well-known 
  habit 
  of 
  usually 
  coming 
  down 
  to 
  the 
  

   ground 
  whenever 
  met 
  by 
  an 
  opposing 
  current, 
  we 
  would 
  suppose 
  such 
  

   a 
  case 
  very 
  rarely 
  if 
  ever 
  occurs. 
  Professor 
  Aughey 
  noticed 
  in 
  one 
  in- 
  

   stance 
  where 
  two 
  swarms 
  were 
  moving 
  in 
  opposite 
  directions, 
  that 
  some 
  

   from 
  the 
  upper 
  column 
  dropped 
  into 
  the 
  lower, 
  where, 
  as 
  a 
  matter 
  of 
  

   course, 
  they 
  could 
  no 
  longer 
  be 
  distinguished 
  from 
  the 
  others, 
  but 
  doubt- 
  

   less 
  were 
  borne 
  along 
  by 
  the 
  current 
  in 
  the 
  direction 
  this 
  column 
  was- 
  

   moving. 
  

  

  There 
  are 
  some 
  other 
  points 
  relating 
  to 
  flight 
  which 
  might 
  properly 
  

   be 
  mentioned 
  here, 
  but 
  as 
  they 
  have 
  some 
  connection 
  with 
  meteorolog- 
  

   ical 
  conditions 
  we 
  will 
  defer 
  mentioning 
  them 
  until 
  we 
  have 
  discussed 
  

   the 
  bearing 
  of 
  meteorological 
  influences 
  on 
  the 
  migrations 
  of 
  locusts. 
  

  

  But 
  this 
  branch 
  of 
  the 
  subject 
  will 
  be 
  included 
  in 
  a 
  separate 
  chapter; 
  

   hence 
  all 
  points 
  inseparably 
  connected 
  therewith 
  will 
  be 
  included 
  in 
  that 
  

   chapter. 
  We 
  will 
  therefore 
  pass 
  to 
  the 
  other 
  divisions 
  of 
  our 
  subject, 
  

   referring 
  to 
  the 
  chapter 
  on 
  meteorology 
  as 
  may 
  be 
  necessary 
  as 
  though 
  

   it 
  had 
  been 
  introduced 
  at 
  this 
  point 
  in 
  our 
  discussion. 
  

  

  Supposed 
  tendency 
  of 
  swarms 
  approaching 
  the 
  sea 
  to 
  drive 
  onicard 
  and" 
  

   fall 
  into 
  it. 
  — 
  In 
  the 
  preceding 
  portion 
  of 
  this 
  chapter 
  relating 
  to 
  locust 
  

   flights 
  in 
  other 
  countries, 
  the 
  reader 
  will 
  observe 
  frequent 
  mention 
  of 
  

  

  "»Biblioth. 
  Univ. 
  de 
  Geneva, 
  1858, 
  272. 
  a 
  «°Reise 
  in 
  Siidrussland, 
  iii, 
  102. 
  *>> 
  I. 
  c-. 
  

  

  