﻿78 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  nated 
  as 
  " 
  foreigners 
  v 
  to 
  distinguish 
  them 
  from 
  those 
  which 
  are 
  bred 
  in 
  

   the 
  temporary 
  region. 
  

  

  b. 
  Returning 
  swarms. 
  — 
  This 
  term 
  has 
  already 
  been 
  explained 
  by 
  the 
  

   use 
  we 
  have 
  made 
  of 
  it 
  in 
  speaking 
  of 
  invading 
  swarms. 
  But 
  there 
  it 
  

   is 
  limited 
  to 
  those 
  which, 
  having 
  been 
  bred 
  in 
  the 
  temporary 
  region 
  

   between 
  the 
  Mississippi 
  and 
  the 
  Bocky 
  Mountains, 
  soon 
  after 
  becoming 
  

   full 
  fledged 
  fly 
  back 
  toward 
  the 
  section 
  from 
  which 
  their 
  progenitors 
  of 
  

   the 
  preceding 
  season 
  came. 
  It 
  may 
  be 
  used 
  in 
  a 
  general 
  sense 
  to 
  apply 
  

   to 
  all 
  swarms 
  returning 
  from 
  the 
  temporary 
  regions 
  to 
  which 
  they 
  or 
  

   their 
  progenitors 
  may 
  have 
  flown 
  to 
  their 
  native 
  habitats. 
  

  

  How 
  far 
  this 
  habit 
  of 
  returning 
  prevails 
  on 
  the 
  Pacific 
  side 
  of 
  the 
  

   permanent 
  area 
  we 
  are 
  as 
  yet 
  unable 
  to 
  say, 
  our 
  data 
  not 
  being 
  sufficient 
  

   to 
  determine. 
  

  

  So 
  far 
  as 
  we 
  have 
  been 
  able 
  to 
  ascertain, 
  the 
  disposition 
  to 
  return 
  to 
  

   the 
  home 
  of 
  their 
  ancestors 
  is 
  not 
  exhibited 
  by 
  P. 
  migratorius 
  ; 
  at 
  least 
  

   we 
  have 
  been 
  unable 
  to 
  find 
  any 
  notice 
  of 
  it 
  in 
  the 
  voluminous 
  locust 
  

   literature 
  of 
  Europe. 
  

  

  Koppen 
  expresses 
  some 
  doubt 
  as 
  to 
  the 
  correctness 
  of 
  the 
  opinion 
  that 
  it 
  

   is 
  a 
  characteristic 
  of 
  the 
  species 
  to 
  move 
  only 
  from 
  the 
  east 
  to 
  the 
  west, 
  

   and 
  cites 
  instances 
  where 
  it 
  has 
  been 
  known 
  to 
  move 
  northward, 
  espe- 
  

   cially 
  on 
  the 
  east 
  side 
  of 
  the 
  Black 
  Sea; 
  but 
  there 
  is 
  nothing 
  whatever 
  

   shown 
  to 
  indicate 
  that 
  there 
  is 
  a 
  disposition 
  of 
  the 
  resulting 
  brood 
  or 
  of 
  

   the 
  invaders 
  to 
  return 
  to 
  their 
  native 
  habitat 
  ; 
  in 
  fact, 
  all 
  the 
  data 
  we 
  

   can 
  find 
  appear 
  to 
  contradict 
  this. 
  It 
  is 
  more 
  than 
  probable 
  that 
  if 
  the 
  

   least 
  indication 
  of 
  this 
  had 
  shown 
  itself 
  it 
  would 
  have 
  been 
  noticed, 
  

   whereas 
  the 
  European 
  writers 
  on 
  locusts 
  assert 
  that 
  they 
  always 
  move 
  

   from 
  the 
  east 
  toward 
  the 
  west. 
  

  

  The 
  difference 
  in 
  this 
  respect 
  between 
  the 
  C. 
  spretus 
  and 
  P. 
  migratorius 
  

   is 
  somewhat 
  remarkable, 
  and 
  as 
  yet 
  we 
  are 
  unable 
  to 
  fully 
  explain 
  it 
  ; 
  

   but 
  of 
  this 
  we 
  will 
  speak 
  more 
  fully 
  when 
  we 
  have 
  noticed 
  the 
  meager 
  

   ■data 
  in 
  reference 
  to 
  the 
  habits 
  of 
  the 
  other 
  species 
  in 
  this 
  respect. 
  

  

  We 
  have 
  no 
  data 
  whatever 
  on 
  this 
  point 
  in 
  reference 
  to 
  C. 
  italicus, 
  

   which 
  indicates 
  that 
  the 
  attention 
  of 
  European 
  entomologists 
  has 
  not 
  

   been 
  called 
  to 
  it, 
  and 
  hence 
  we 
  presume 
  is 
  not 
  so 
  marked 
  as 
  in 
  C. 
  spretus. 
  

  

  The 
  general 
  direction 
  of 
  the 
  movements 
  of 
  A. 
  peregrinum 
  varies 
  in 
  dif- 
  

   ferent 
  sections 
  ; 
  in 
  Northern 
  Africa, 
  west 
  of 
  Egypt, 
  the 
  invading 
  swarms 
  

   are 
  from 
  the 
  south, 
  as 
  asserted 
  by 
  Lallemant 
  and 
  Girard, 
  come 
  from 
  

   the 
  region 
  of 
  the 
  Atlas 
  range. 
  South 
  of 
  this 
  range, 
  in 
  Central 
  Africa, 
  

   the 
  invading 
  swarms 
  move 
  southward 
  and 
  southwest; 
  m 
  in 
  Egypt 
  and 
  

   Arabia 
  the 
  movements 
  vary, 
  but 
  are 
  generally 
  more 
  or 
  less 
  east 
  and 
  west. 
  

  

  In 
  the 
  states 
  of 
  North 
  Africa, 
  as 
  we 
  might 
  suppose, 
  there 
  are 
  indica- 
  

   tions 
  of 
  a 
  return 
  movement 
  similar 
  to 
  that 
  observed 
  in 
  the 
  case 
  of 
  G. 
  

   spretus. 
  Lallemant 
  m 
  states 
  that 
  the 
  locusts 
  that 
  live 
  for 
  a 
  long 
  time 
  in 
  

   the 
  adult 
  state 
  become 
  a 
  rosy 
  color, 
  and 
  at 
  length 
  migrate 
  southward 
  

  

  i« 
  Girard, 
  in 
  Ann. 
  Soc. 
  Ent. 
  France, 
  4th 
  Ser. 
  1867, 
  Bull, 
  x-xii. 
  

   174 
  See 
  last 
  quoted 
  authority. 
  

  

  