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  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  CHAPTER 
  VI. 
  

  

  THE 
  SOUTHERN 
  LIMITS 
  OF 
  THE 
  DISTRIBUTION 
  OF 
  THE 
  

   ROOKY 
  MOUNTAIN 
  LOCUST. 
  

  

  In 
  view 
  of 
  the 
  probable 
  speedy 
  completion 
  of 
  the 
  Atchison, 
  Topeka, 
  

   and 
  Santa 
  Fe" 
  Railroad 
  and 
  the 
  Southern 
  Pacific 
  Railroad, 
  and 
  the 
  pro- 
  

   jected 
  lines 
  of 
  the 
  Atlantic 
  and 
  Pacific, 
  and 
  Southern 
  Pacific 
  Railroads 
  

   connecting 
  the 
  Pacific 
  coast 
  and 
  Gulf 
  States, 
  as 
  well 
  as 
  the 
  lower 
  valley 
  

   of 
  the 
  Mississippi 
  River, 
  and 
  thus 
  opening 
  up 
  to 
  settlement 
  the 
  arable 
  

   lands 
  of 
  portions 
  of 
  New 
  Mexico 
  and 
  Arizona, 
  it 
  has 
  become 
  of 
  a 
  good 
  

   deal 
  of 
  practical 
  importance 
  to 
  define 
  with 
  some 
  degree 
  of 
  certainty 
  the 
  

   southern 
  limits 
  of 
  the 
  distribution 
  of 
  the 
  Rocky 
  Mountain 
  locust. 
  

  

  For 
  this 
  purpose 
  we 
  made 
  a 
  journey 
  in 
  the 
  summer 
  of 
  1879 
  to 
  Santa 
  

   Fe, 
  N. 
  Mex., 
  and 
  adjoining 
  places, 
  and 
  were 
  able 
  to 
  obtain 
  much 
  new 
  

   information 
  regarding 
  the 
  distribution 
  of 
  this 
  locust 
  in 
  New 
  Mexico 
  and 
  

   also 
  to 
  learn 
  something 
  of 
  its 
  occurrence 
  in 
  the 
  adjoining 
  Territory 
  of 
  

   Arizona. 
  The 
  facts 
  collected 
  have 
  been 
  embodied 
  in 
  the 
  map 
  accom- 
  

   panying 
  this 
  report 
  and 
  in 
  the 
  pages 
  farther 
  on. 
  

  

  It 
  appears 
  from 
  our 
  investigations 
  that 
  the 
  permanent 
  breeding 
  

   grounds 
  of 
  the 
  locust 
  scarcely 
  extend 
  into 
  New 
  Mexico, 
  and 
  probably 
  not 
  

   at 
  all 
  into 
  Arizona. 
  The 
  area, 
  however, 
  into 
  which 
  they 
  periodically 
  emi- 
  

   grate 
  from 
  the 
  permanent 
  region 
  embraces 
  the 
  northern 
  half 
  of 
  New 
  

   Mexico 
  and 
  the 
  northeastern 
  corner 
  of 
  Arizona, 
  i. 
  6., 
  that 
  portion 
  adjacent 
  

   to 
  New 
  Mexico 
  and 
  possibly 
  to 
  Utah. 
  From 
  this 
  it 
  appears 
  that 
  those 
  

   portions 
  of 
  the 
  valleys 
  of 
  the 
  Pecos 
  and 
  Rio 
  Grande 
  Rivers 
  lying 
  in 
  the 
  

   northern 
  two-thirds 
  of 
  the 
  Territory 
  of 
  New 
  Mexico 
  are 
  periodically 
  in- 
  

   vaded 
  by 
  the 
  Rocky 
  Mountain 
  locust, 
  the 
  source 
  of 
  supply 
  being 
  the 
  

   mountain 
  valleys 
  and 
  parks 
  of 
  Southern 
  and 
  Southwestern 
  Colorado. 
  

   But 
  it 
  is 
  most 
  probable 
  that 
  the 
  fertile 
  valley 
  of 
  the 
  Rio 
  Grande 
  lying 
  

   south 
  of 
  Fort 
  Craig, 
  and 
  most 
  valuable 
  as 
  a 
  wine-growing 
  district, 
  will 
  

   never 
  suffer 
  from 
  the 
  invasions 
  of 
  this 
  pest. 
  

  

  To 
  recapitulate 
  what 
  the 
  Commission 
  has 
  been 
  able 
  to 
  ascertain 
  re- 
  

   garding 
  the 
  southern 
  limits 
  of 
  the 
  locust 
  region, 
  we 
  may 
  say 
  that 
  in 
  

   Texas 
  it 
  reaches, 
  and 
  is 
  bounded 
  on 
  the 
  south 
  by, 
  the 
  Rio 
  Grande; 
  in 
  one 
  

   year 
  # 
  the 
  locusts 
  having 
  crossed 
  the 
  river 
  and 
  entered 
  Mexican 
  territory 
  

   for 
  the 
  distance 
  of 
  a 
  mile 
  or 
  so. 
  The 
  species 
  is 
  apparently 
  absent 
  from 
  

   Southern 
  New 
  Mexico 
  and 
  from 
  Central 
  and 
  Southern 
  Arizona, 
  as 
  well 
  

   as 
  from 
  Southern 
  Nevada 
  ; 
  unless 
  it 
  should 
  eventually 
  be 
  found 
  existing 
  

   in 
  limited 
  numbers 
  on 
  the 
  subalpine 
  mountain 
  peaks 
  of 
  these 
  regions. 
  

   There 
  is 
  every 
  probability 
  that 
  the 
  locust 
  (Caloptonts 
  spretus) 
  will 
  not 
  

   be 
  found 
  in 
  Lower 
  California 
  and 
  the 
  Peninsula 
  of 
  California, 
  and 
  that 
  

   it 
  does 
  not 
  inhabit 
  Mexico. 
  That 
  this 
  is 
  the 
  case 
  seems 
  probable 
  from 
  

  

  * 
  1873. 
  Soo 
  First 
  Report 
  of 
  the 
  Commission, 
  pp. 
  59, 
  60. 
  

  

  