﻿GENERAL 
  REPORT 
  FOR 
  1881. 
  29^ 
  

  

  Both 
  the 
  lower 
  and 
  upper 
  lines 
  descend 
  in 
  passing 
  from 
  south 
  to 
  north 
  ; 
  

   that 
  is, 
  the 
  timber 
  districts 
  are 
  found 
  at 
  lower 
  altitudes 
  in 
  the 
  northern 
  

   portion 
  of 
  the 
  Arid 
  or 
  Eockj^ 
  Mountain 
  Eegion 
  than 
  in 
  the 
  southern 
  por- 
  

   tion. 
  This 
  is 
  due 
  to 
  the 
  decrease 
  in 
  temperature 
  as 
  we 
  pass 
  from 
  south 
  

   to 
  north. 
  The 
  forests 
  are 
  chiefly 
  of 
  pines, 
  spruce, 
  cedars, 
  and 
  fir, 
  but 
  

   the 
  pines 
  are 
  of 
  principal 
  value. 
  Below 
  these 
  timbered 
  regions, 
  on 
  the 
  

   lower 
  slopes 
  of 
  mountains, 
  on 
  the 
  mesas 
  and 
  hills, 
  low, 
  scattered 
  forests 
  

   are 
  often 
  found, 
  composed 
  chiefly 
  of 
  dwarfed 
  piuon 
  i)ines 
  and 
  scrubby 
  

   cedars. 
  

  

  Of 
  course 
  that 
  i>ortion 
  of 
  the 
  Arid 
  Eegion 
  described 
  as 
  the 
  timber- 
  

   bearing 
  region 
  is 
  much 
  larger 
  than 
  that 
  actually 
  covered 
  -by 
  forests 
  ; 
  

   but 
  this 
  is 
  to 
  a 
  great 
  extent 
  due 
  to 
  the 
  destructive 
  agency 
  of 
  fires 
  that 
  

   annually 
  destroy 
  inconceivable 
  quantities 
  of 
  timber. 
  These 
  regions 
  

   comprise 
  from 
  20 
  to 
  25 
  per 
  cent, 
  of 
  the 
  Arid 
  Eegion, 
  though 
  at 
  least 
  one 
  

   half 
  has 
  been 
  denuded 
  or 
  is 
  kept 
  bare 
  hj 
  the 
  above-mentioned 
  agency. 
  

   This 
  region, 
  too, 
  is 
  very 
  much 
  like 
  the 
  temporary 
  region 
  of 
  this 
  locust 
  in 
  

   the 
  annual 
  precipitation 
  of 
  moisture, 
  and 
  hence 
  these 
  bare 
  portions 
  are 
  

   not 
  so 
  frequently 
  chosen 
  as 
  localities 
  for 
  egg-depositing 
  as 
  are 
  those, 
  

   lying 
  immediately 
  below 
  this 
  line, 
  that 
  have 
  been 
  described 
  as 
  grazing 
  

   lands. 
  

  

  The 
  area 
  of 
  the 
  Arid 
  Eegion 
  the 
  altitude 
  of 
  which 
  is 
  greater 
  than 
  the 
  

   forest 
  region 
  is 
  comparatively 
  small, 
  and 
  comprises 
  mountain 
  peaks 
  and 
  

   parts 
  of 
  mountain 
  ranges 
  that 
  extend 
  above 
  the 
  line 
  of 
  perpetual 
  snow 
  

   or 
  rigorous 
  climate. 
  Yery 
  seldom 
  do 
  any 
  of 
  these 
  locusts 
  choose 
  the 
  

   warmer 
  portions 
  of 
  this 
  region 
  as 
  breeding 
  grounds, 
  since 
  it 
  is 
  too 
  un- 
  

   certain 
  and 
  quite 
  humid, 
  although 
  tlie 
  greater 
  portion 
  of 
  the 
  moisture 
  

   that 
  falls 
  here 
  is 
  in 
  the 
  form 
  of 
  snow 
  and 
  hail. 
  ISTeither 
  do 
  they 
  fre- 
  

   quent 
  the 
  mauvaises 
  terres, 
  deserts, 
  lava 
  beds, 
  or 
  chaparral 
  lands. 
  Then 
  

   we 
  have 
  remaining 
  the 
  two 
  other 
  regions 
  as 
  the 
  true 
  home 
  and 
  breeding- 
  

   grounds 
  of 
  this 
  insect, 
  viz., 
  the 
  irrigable 
  lands 
  and 
  the 
  grazing 
  lands. 
  

   Of 
  course 
  great 
  numbers 
  of 
  locusts 
  are 
  annually 
  bred 
  within 
  and 
  even 
  

   above 
  the 
  forest 
  region 
  of 
  the 
  Eocky 
  Mountain 
  system, 
  but, 
  as 
  before 
  

   stated, 
  the 
  humidity 
  of 
  this 
  area 
  is 
  too 
  great, 
  and 
  hence 
  it 
  follows 
  that 
  

   these 
  cannot 
  be 
  as 
  vigorous 
  as 
  those 
  bred 
  below 
  and 
  in 
  a 
  more 
  arid 
  cli- 
  

   mate. 
  That 
  this 
  insect 
  does 
  not 
  require 
  nor 
  seek 
  a 
  high 
  temperature, 
  

   we 
  are 
  aware 
  from 
  the 
  condition 
  of 
  the 
  climate 
  in 
  those 
  i)ortions 
  of 
  

   British 
  America 
  where 
  it 
  breeds 
  in 
  such 
  overwhelming 
  numbers. 
  

  

  This 
  region, 
  which 
  is 
  known 
  as 
  the 
  x^ermanent 
  breeding-grounds 
  of 
  

   the 
  Eocky 
  Mountain 
  locust, 
  as 
  before 
  stated, 
  comprises 
  all 
  that 
  region 
  

   west 
  and 
  north 
  of 
  the 
  deserts 
  where 
  the 
  annual 
  rainfall 
  is 
  less 
  than 
  

   20 
  inches, 
  an 
  area 
  of 
  about 
  300,000 
  square 
  miles. 
  Of 
  course 
  they 
  do 
  not 
  

   breed 
  throughout 
  this 
  entire 
  region 
  annually, 
  nor 
  on 
  all 
  the 
  surface 
  5 
  

   but 
  it 
  is 
  because 
  they 
  are 
  always 
  to 
  be 
  found 
  in 
  some 
  portion 
  of 
  it 
  in 
  

   greater 
  or 
  less 
  numbers, 
  and 
  because 
  they 
  can 
  continue 
  to 
  exist 
  year 
  

   after 
  year 
  without 
  becoming 
  diseased, 
  that 
  this 
  name 
  has 
  been 
  given 
  to 
  

   the 
  region. 
  

  

  