﻿THE 
  PERMANENT 
  REEGION. 
  15" 
  

  

  The 
  effect 
  the 
  locust 
  question 
  is 
  likely 
  to 
  have 
  on 
  the 
  agriculture 
  of 
  

   the 
  temporary 
  region 
  east 
  of 
  the 
  Rocky 
  Mountains, 
  the 
  boundaries 
  of 
  

   which 
  we 
  have 
  found 
  no 
  reason 
  for 
  changing 
  in 
  any 
  essential 
  particular 
  

   from 
  what 
  was 
  given 
  in 
  map 
  ]STo. 
  1 
  of 
  our 
  first 
  report, 
  depends 
  very 
  

   largely 
  upon 
  the 
  solution 
  of 
  the 
  problem 
  so 
  far 
  as 
  it 
  relates 
  to 
  the 
  per- 
  

   manent 
  region. 
  We 
  shall 
  therefore 
  consider 
  first 
  this 
  division 
  of 
  the 
  

   subject. 
  

  

  First. 
  As 
  to 
  the 
  Permanent 
  Region. 
  

  

  Since 
  the 
  publication 
  of 
  our 
  first 
  report 
  the 
  facts 
  obtained 
  have 
  forced 
  

   us 
  to 
  the 
  conclusion 
  that 
  the 
  boundaries 
  of 
  this 
  region 
  will 
  have 
  to 
  be 
  

   exteuded 
  through 
  more 
  of 
  the 
  northern 
  part 
  of 
  Nebraska 
  and 
  of 
  Dakota 
  

   than 
  is 
  included 
  in 
  our 
  first 
  map. 
  The 
  change 
  we 
  consider 
  necessary 
  is 
  

   marked 
  in 
  the 
  new 
  map 
  given 
  in 
  the 
  present 
  volume. 
  The 
  reader 
  should 
  

   bear 
  in 
  mind 
  that 
  by 
  the 
  term 
  "permanent" 
  we 
  do 
  not 
  wish 
  to 
  convey 
  

   the 
  idea 
  that 
  the 
  locusts 
  are 
  to 
  be 
  found 
  breeding 
  in 
  all 
  parts 
  of 
  this 
  

   area 
  each 
  year, 
  as 
  we 
  have 
  stated 
  in 
  this 
  and 
  our 
  former 
  report 
  that 
  they 
  

   are 
  essentially 
  migratory 
  within 
  this 
  region, 
  continuiug 
  in 
  some 
  sections 
  

   for 
  a 
  year 
  or 
  two, 
  and 
  then 
  changing 
  to 
  others, 
  but 
  that 
  they 
  are 
  capable 
  

   of 
  continuing 
  their 
  race 
  in 
  any 
  part 
  of 
  this 
  region 
  ; 
  that 
  it 
  differs 
  in 
  this 
  

   respect 
  from 
  the 
  temporary 
  region. 
  In 
  the 
  latter 
  the 
  climatic 
  conditions 
  

   are 
  such 
  that 
  they 
  do 
  not 
  appear 
  to 
  be 
  capable 
  of 
  continuiug 
  their 
  race, 
  

   the 
  progeny 
  of 
  invading 
  swarms 
  deteriorating 
  and 
  finally 
  fading 
  out 
  

   unless 
  they 
  return 
  to 
  their 
  native 
  habitats. 
  That 
  the 
  boundaries 
  be- 
  

   tween 
  these 
  two 
  regions 
  cannot 
  be 
  marked 
  with 
  definite 
  accuracy 
  we 
  

   admit, 
  and 
  hence 
  in 
  our 
  former 
  report 
  mapped 
  out 
  an 
  intermediate 
  area 
  

   to 
  which 
  we 
  applied 
  the 
  term 
  sub-permanent 
  region, 
  and, 
  as 
  will 
  be 
  seen 
  

   by 
  reference 
  to 
  the 
  new 
  map 
  in 
  this 
  volume, 
  we 
  have 
  still 
  retained 
  this 
  

   region, 
  though 
  somewhat 
  circumscribed. 
  But 
  the 
  exact 
  boundary 
  is 
  a 
  

   matter 
  of 
  little 
  importance 
  practically 
  ; 
  the 
  two 
  regions 
  as 
  such 
  are 
  very 
  

   easily 
  distinguished 
  from 
  each 
  other 
  by 
  marked 
  characteristics. 
  

  

  In 
  the 
  permanent 
  region, 
  which 
  embraces 
  the 
  Rocky 
  Mountain 
  pla- 
  

   teau 
  and 
  the 
  bordering 
  plains 
  from 
  the 
  middle 
  of 
  Colorado 
  northward, 
  

   the 
  rainfall 
  is 
  insufficient 
  for 
  agricultural 
  purposes, 
  and 
  hence 
  irrigation 
  

   has 
  to 
  be 
  resorted 
  to 
  j 
  in 
  the 
  temporary 
  region 
  this 
  is 
  unnecessary 
  ; 
  the 
  

   plains 
  and 
  plateaus 
  of 
  the 
  permanent 
  region 
  are 
  to 
  a 
  large 
  extent 
  dis- 
  

   tinguished 
  by 
  the 
  presence 
  of 
  Artemesia, 
  Chenopodiaceous 
  plants, 
  and 
  

   what 
  is 
  usually 
  termed 
  "bunch-grass 
  ;" 
  in 
  short 
  by 
  all 
  the 
  characteris- 
  

   tics 
  of 
  a 
  drier 
  climate. 
  One 
  other 
  peculiarity 
  which 
  should 
  not 
  be 
  over- 
  

   looked 
  appears 
  to 
  mark 
  roughly 
  the 
  southern 
  boundary 
  of 
  the 
  permanent 
  

   home 
  of 
  the 
  Rocky 
  Mountain 
  locust, 
  and 
  that 
  is 
  the 
  isothermal 
  curve 
  or 
  

   line 
  of 
  the 
  50° 
  of 
  mean 
  annual 
  temperature, 
  which 
  also 
  corresponds 
  very 
  

   nearly 
  with 
  the 
  isotheral 
  curve 
  or 
  line 
  of 
  summer 
  temperature 
  of 
  70°. 
  

   But 
  this 
  applies 
  only 
  to 
  that 
  portion 
  of 
  the 
  region 
  which 
  extends 
  upon 
  

   the 
  plains 
  east 
  of 
  the 
  mountains. 
  

  

  If 
  any 
  practical 
  means 
  of 
  exterminating 
  the 
  locusts 
  in 
  this 
  permanent 
  

   region 
  could 
  be 
  devised 
  the 
  whole 
  locust 
  problem 
  could 
  be 
  solved, 
  and 
  

  

  