﻿58 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  more 
  restricted 
  area 
  within 
  the 
  limits 
  of 
  their 
  migrations, 
  our 
  first 
  step 
  

   in 
  trying 
  to 
  fix. 
  the 
  boundaries 
  of 
  this 
  area 
  for 
  G. 
  spretus 
  was 
  to 
  deter- 
  

   mine 
  as 
  nearly 
  as 
  possible 
  the 
  outer 
  limits 
  of 
  its 
  geographical 
  distribu- 
  

   tion. 
  This 
  was 
  not 
  difficult, 
  except 
  where 
  the 
  line 
  runs 
  through 
  unin- 
  

   habited 
  sections 
  from 
  which 
  no 
  data 
  could 
  be 
  obtained 
  ; 
  as 
  this 
  limit, 
  so 
  

   far 
  as 
  this 
  species 
  is 
  concerned, 
  is 
  determined 
  not 
  by 
  straggling 
  indi- 
  

   viduals, 
  but 
  by 
  the 
  utmost 
  points 
  to 
  which 
  flying 
  swarms 
  reach, 
  for 
  

   beyond 
  these 
  points 
  stray 
  individuals 
  are 
  seldom 
  seen. 
  

  

  This 
  outer 
  limit 
  of 
  geographical 
  distribution 
  is 
  found 
  marked 
  in 
  map 
  

   No. 
  1 
  of 
  our 
  former 
  report, 
  which 
  is 
  repeated 
  in 
  the 
  present 
  volume. 
  

   The 
  southern 
  limit, 
  which 
  is 
  supposed 
  to 
  pass 
  through 
  New 
  Mexico 
  and 
  

   Arizona, 
  has 
  not 
  been 
  determined 
  with 
  satisfactory 
  certainty, 
  and 
  it 
  may 
  

   be 
  that, 
  as 
  mapped 
  through 
  Texas, 
  it 
  is 
  slightly 
  incorrect, 
  as 
  it 
  is 
  possi- 
  

   ble 
  that 
  the 
  species 
  extends 
  its 
  migrations 
  into 
  Eastern 
  Mexico. 
  It 
  is 
  

   even 
  possible 
  that 
  the 
  locust 
  which 
  occasionally 
  devastates 
  other 
  parts 
  

   of 
  Mexico 
  is 
  Galoptenus 
  spretus, 
  but 
  we 
  think 
  otherwise. 
  We 
  also 
  know, 
  

   from 
  personal 
  examination 
  of 
  specimens, 
  that 
  the 
  species 
  which 
  occa- 
  

   sionally 
  overruns 
  Honduras, 
  the 
  southern 
  districts 
  of 
  Mexico, 
  and 
  Central 
  

   America 
  is 
  quite 
  distinct, 
  and 
  believe 
  that 
  the 
  Eocky 
  Mountain 
  locust, 
  

   with 
  the 
  exception 
  of 
  occasional 
  visits 
  to 
  the 
  southern 
  side 
  of 
  the 
  lower 
  

   Rio 
  Grande 
  Valley, 
  never 
  goes 
  south 
  of 
  the 
  United 
  States 
  boundary. 
  

  

  Our 
  reasons 
  for 
  this 
  opinion 
  may 
  be 
  briefly 
  stated 
  as 
  follows 
  : 
  The 
  0. 
  

   spretus 
  is 
  evidently, 
  as 
  we 
  have 
  shown 
  in 
  our 
  former 
  report, 
  a 
  boreal 
  in- 
  

   sect. 
  We 
  cannot 
  learn 
  that 
  any 
  of 
  the 
  collections 
  of 
  insects 
  made 
  in 
  

   Mexico 
  contain 
  this 
  species, 
  and 
  we 
  have 
  been 
  unable 
  to 
  obtain 
  any 
  evi- 
  

   dence 
  of 
  its 
  being 
  found 
  in 
  that 
  country. 
  So 
  far 
  as 
  it 
  is 
  possible 
  to 
  

   judge 
  in 
  reference 
  to 
  the 
  species, 
  in 
  the 
  accounts 
  of 
  locust 
  ravages 
  in 
  

   Mexico 
  and 
  Central 
  America, 
  they 
  appear 
  to 
  differ 
  from 
  G. 
  spretus. 
  In 
  

   the 
  account 
  given 
  by 
  Gage, 
  in 
  his 
  "New 
  Survey 
  of 
  West 
  Indies," 
  154 
  it 
  is 
  

   stated 
  "They 
  were 
  after 
  the 
  manner 
  of 
  our 
  grasshoppers, 
  but 
  somewhat 
  

   bigger;" 
  also, 
  that 
  "where 
  they 
  lighted, 
  either 
  upon 
  trees 
  or 
  standing 
  

   corn, 
  there 
  nothing 
  was 
  expected 
  but 
  ruin," 
  &c. 
  The 
  size 
  indicated 
  here 
  

   is 
  certainly 
  larger 
  than 
  our 
  Rocky 
  Mountain 
  locust 
  ; 
  and, 
  secondly, 
  the 
  

   allusion 
  to 
  their 
  alighting 
  on 
  trees 
  is 
  more 
  applicable 
  to 
  the 
  habit 
  of 
  

   Acridium 
  americanum 
  and 
  its 
  congeners 
  than 
  to 
  C. 
  spretus. 
  The 
  locust 
  

   alluded 
  to 
  by 
  Squiers 
  155 
  is 
  evidently 
  too 
  large 
  for 
  our 
  species, 
  measuring, 
  

   according 
  to 
  his 
  statement, 
  "two 
  and 
  a 
  half 
  to 
  four 
  inches." 
  

  

  Those 
  which 
  have 
  of 
  recent 
  years 
  appeared 
  in 
  Yucatan 
  are 
  evidently 
  

   species 
  of 
  Acridium. 
  Some 
  specimens 
  were 
  sent 
  to 
  Mr. 
  S. 
  H. 
  Scudder, 
  

   most 
  of 
  which 
  proved 
  to 
  be 
  A. 
  americanum) 
  a 
  few 
  specimens 
  were 
  ob- 
  

   served 
  of 
  an 
  unknown 
  species 
  allied 
  to 
  A. 
  flavofasciatum 
  156 
  . 
  Specimens 
  

   received 
  during 
  the 
  past 
  season 
  from 
  the 
  West 
  Indies, 
  which 
  give 
  in- 
  

   dubitable 
  evidence 
  of 
  having 
  migrated, 
  cannot 
  be 
  distinguished 
  from 
  

   A. 
  peregrinum, 
  the 
  ultimate 
  segment 
  of 
  the 
  male 
  abdomen 
  distinguishing 
  

  

  164 
  See 
  former 
  Report, 
  pp. 
  461-2. 
  

  

  165 
  Quoted 
  in 
  our 
  former 
  Report, 
  p. 
  460. 
  

  

  166 
  See 
  former 
  Report, 
  p. 
  462. 
  

  

  