﻿GENERAL 
  REPORT 
  FOR 
  1881. 
  31 
  

  

  of 
  Northern 
  Wyoming, 
  while 
  the 
  central 
  and 
  southern 
  regions 
  inter- 
  

   change 
  swarms 
  directly. 
  

  

  While 
  it 
  would 
  appear 
  that 
  this 
  interchange 
  of 
  swarms 
  between 
  these 
  

   several 
  centers 
  was 
  intentional, 
  by 
  a 
  closer 
  examination 
  into 
  the 
  habits 
  

   of 
  this 
  insect 
  and 
  the 
  influencing 
  agents 
  in 
  its 
  migrations, 
  we 
  can 
  readily 
  

   see 
  that 
  such 
  is 
  not 
  the 
  fact. 
  ^Nevertheless, 
  every 
  object 
  is 
  accom- 
  

   plished 
  in 
  this 
  way 
  that 
  could 
  be 
  were 
  they 
  made 
  from 
  impulse 
  or 
  desire. 
  

   By 
  the 
  interchange 
  of 
  swarms 
  there 
  is 
  cross-breeding 
  of 
  unrelated 
  and 
  

   distant 
  individuals, 
  thus 
  preventing 
  the 
  deteriorating 
  influence 
  of 
  a 
  

   long- 
  continued 
  interbreeding. 
  Also, 
  by 
  having 
  these 
  widely 
  separated 
  

   regions 
  of 
  large 
  area, 
  moving 
  swarms 
  of 
  great 
  magnitude 
  are 
  enabled 
  

   to 
  recuperate 
  from 
  the 
  fatigues 
  of 
  travel 
  and 
  rear 
  healthy 
  oifspring, 
  to 
  

   return 
  to 
  their 
  starting 
  point 
  when 
  the 
  favorable 
  opportunity 
  presents 
  

   itself. 
  

  

  As 
  irregular 
  as 
  appear 
  to 
  be 
  the 
  movements 
  of 
  swarms 
  of 
  locusts 
  in 
  

   the 
  widely 
  separated 
  areas 
  to 
  one 
  who 
  has 
  not 
  given 
  the 
  subject 
  a 
  close 
  

   study, 
  it 
  is, 
  nevertheless, 
  a 
  conceded 
  fact 
  that 
  they 
  seem 
  to 
  have 
  leading 
  

   routes 
  which 
  they 
  follow. 
  So 
  marked 
  is 
  this 
  rule 
  in 
  certain 
  localities 
  

   that 
  it 
  is 
  difficult 
  to 
  learn 
  of 
  any 
  exceptions. 
  An 
  example 
  of 
  this 
  nature 
  

   is 
  that 
  of 
  their 
  movements 
  on 
  the 
  Upper 
  Bear 
  Eiver 
  and 
  in 
  portions 
  of 
  

   Western 
  Wyoming, 
  where 
  every 
  swarm 
  of 
  which 
  I 
  could 
  obtain 
  any 
  

   information 
  came 
  from 
  the 
  west 
  and 
  northwest 
  and 
  flew 
  to 
  the 
  east, 
  

   northeast, 
  or 
  southeast. 
  They 
  also 
  appear 
  to 
  fly 
  in 
  great 
  circles 
  in 
  sev- 
  

   eral 
  sections 
  of 
  the 
  West. 
  The 
  cause 
  of 
  this 
  phenomenon 
  is 
  the 
  com- 
  

   bined 
  influence 
  of 
  prevailing 
  winds 
  and 
  surface 
  configuration 
  on 
  mov- 
  

   ing 
  swarms. 
  For 
  an 
  example 
  of 
  this 
  peculiar 
  movement 
  we 
  will 
  take 
  

   a 
  swarm 
  that 
  leaves 
  the 
  great 
  center 
  of 
  distribution 
  in 
  Montana 
  towards 
  

   the 
  southwest 
  by 
  way 
  of 
  the 
  Gallatin 
  and 
  Madison 
  Yalleys 
  and 
  low 
  

   passes 
  across 
  to 
  the 
  upper 
  waters 
  of 
  the 
  Snake 
  Eiver. 
  These, 
  after 
  en- 
  

   tering 
  this 
  latter 
  valley, 
  follow 
  down 
  that 
  stream 
  to 
  where 
  it 
  makes 
  an 
  

   abrupt 
  bend 
  to 
  the 
  west. 
  Here 
  the 
  swarms 
  generally 
  divide, 
  some 
  con- 
  

   tinuing 
  down 
  the 
  stream, 
  while 
  the 
  remaining 
  portion 
  of 
  the 
  swarm 
  

   works 
  on 
  south 
  and 
  southeast 
  over 
  the 
  low 
  mountains 
  to 
  Bear 
  Elver 
  

   Yalley 
  and 
  into 
  the 
  great 
  interior 
  basin. 
  Those 
  which 
  strike 
  the 
  valley 
  

   of 
  Bear 
  Eiver 
  mostly 
  turn 
  up 
  the 
  stream 
  and 
  wend 
  their 
  way 
  toward 
  

   the 
  east 
  and 
  southeast 
  until 
  the 
  vicinity 
  of 
  Green 
  Eiver 
  is 
  reached, 
  when 
  

   they 
  again 
  slightly 
  change 
  their 
  course 
  by 
  swinging 
  to 
  the 
  east 
  and 
  

   northeast. 
  From 
  here 
  their 
  course 
  is 
  eastward 
  to 
  the 
  Platte, 
  when 
  they 
  

   again 
  divide, 
  a 
  portion 
  following 
  up 
  and 
  the 
  other 
  portion 
  following 
  

   down 
  this 
  stream. 
  The 
  latter, 
  after 
  passing 
  through 
  the 
  canon 
  out 
  upon 
  

   the 
  plains, 
  are 
  struck 
  by 
  south 
  and 
  southeast 
  winds 
  and 
  carried 
  to 
  the 
  

   northeast 
  toward 
  the 
  Black 
  Hills, 
  and 
  from 
  this 
  point 
  return 
  to 
  south- 
  

   ern 
  Montana 
  and 
  finally 
  to 
  their 
  starting 
  point. 
  Those 
  that 
  follow 
  

   up 
  the 
  Platte 
  cross 
  over 
  the 
  range 
  by 
  way 
  of 
  the 
  various 
  passes 
  into 
  

   Eastern 
  Colorado, 
  and 
  either 
  work 
  south 
  through 
  this 
  State 
  into 
  IS'ew 
  

   Mexico, 
  or 
  drift 
  out 
  on 
  the 
  plains 
  into 
  Western 
  Kansas 
  and 
  Nebraska, 
  

  

  