﻿C. 
  SPRETUS 
  ALWAYS 
  MIGRATORY. 
  73 
  

  

  When 
  Mr. 
  Thomas 
  began 
  to 
  study 
  them 
  in 
  the 
  field 
  in 
  1809, 
  he 
  was 
  

   led 
  to 
  believe 
  from 
  his 
  observations 
  of 
  that 
  season 
  that 
  they 
  are 
  nor- 
  

   mally 
  sedentary, 
  but 
  subsequent 
  investigations 
  have 
  served 
  to 
  convince 
  

   him 
  as 
  well 
  as 
  the 
  other 
  members 
  of 
  the 
  Commission 
  that 
  they 
  are 
  es- 
  

   sentially 
  migratory 
  in 
  their 
  native 
  habitats. 
  

  

  The 
  evidence 
  upon 
  whieh 
  this 
  conclusion 
  is 
  founded 
  consists 
  of 
  the 
  

   numerous 
  facts 
  gathered 
  from 
  the 
  various 
  sections 
  of 
  the 
  mountain 
  area, 
  

   showing 
  that 
  year 
  after 
  year 
  they 
  are 
  observed 
  migrating 
  in 
  greater 
  or 
  

   less 
  swarms 
  from 
  point 
  to 
  point 
  within 
  that 
  area. 
  Also 
  the 
  fact 
  that 
  

   in 
  the 
  mountain 
  valleys 
  and 
  canons, 
  during 
  years 
  when 
  there 
  is 
  no 
  gen- 
  

   eral 
  movement, 
  little 
  swarms 
  may 
  be 
  seen 
  rising 
  and 
  flying 
  away 
  to 
  other 
  

   points. 
  Last 
  season 
  Mr. 
  Thomas, 
  while 
  on 
  the 
  top 
  of 
  Pike's 
  Peak, 
  cap- 
  

   tured 
  two 
  or 
  three 
  full-fledged 
  individuals 
  which 
  had 
  probably 
  been 
  

   brought 
  down 
  by 
  the 
  rain 
  of 
  the 
  preceding 
  evening 
  in 
  their 
  attempt 
  to 
  

   pass 
  over, 
  yet 
  no 
  swarm 
  was 
  observed 
  passing 
  during 
  the 
  entire 
  season. 
  

  

  It 
  is, 
  therefore, 
  evident 
  that 
  their 
  flights 
  do 
  not 
  depend 
  upon 
  numbers, 
  

   but 
  that 
  the 
  brood 
  of 
  a 
  single 
  female, 
  when 
  they 
  attain 
  the 
  proper 
  age, 
  

   •will 
  migrate. 
  

  

  Another 
  fact, 
  which 
  has 
  been 
  repeatedly 
  observed, 
  tends 
  to 
  confirm 
  

   this 
  opinion, 
  to 
  wit, 
  that 
  they 
  do 
  not 
  breed 
  annually 
  over 
  the 
  entire 
  Per- 
  

   manent 
  area. 
  In 
  passing 
  over 
  the 
  mountain 
  section 
  of 
  Wyoming, 
  Col- 
  

   orado, 
  Utah, 
  Idaho, 
  and 
  Montana, 
  we 
  have 
  found 
  it 
  universally 
  the 
  case 
  

   that 
  they 
  are 
  confined 
  to 
  limited 
  districts 
  which 
  are 
  much 
  more 
  extended 
  

   in 
  some 
  years 
  than 
  others. 
  A 
  section 
  infested 
  in 
  one 
  year 
  may 
  be 
  en- 
  

   tirely 
  free 
  the 
  next. 
  That 
  certain 
  favorable 
  points 
  are 
  more 
  generally 
  

   >selected 
  as 
  breeding 
  grounds 
  than 
  others 
  is 
  certainly 
  true. 
  

  

  It 
  is 
  true, 
  there 
  is 
  some 
  evidence 
  which 
  tends 
  to 
  cast 
  doubt 
  upon 
  the 
  

   correctness 
  of 
  our 
  conclusions 
  on 
  this 
  point 
  ; 
  for 
  example, 
  the 
  repeated 
  

   finding 
  of 
  specimens 
  throughout 
  the 
  summer 
  in 
  localities 
  where 
  no 
  migra- 
  

   tions 
  have 
  been 
  observed 
  ; 
  but 
  the 
  flight 
  of 
  a 
  few 
  grasshoppers 
  in 
  these 
  

   sections 
  is 
  so 
  common 
  an 
  occurrence 
  that 
  it 
  is 
  not 
  likely 
  to 
  attract 
  at- 
  

   tention. 
  It 
  is 
  more 
  than 
  probable 
  that 
  many 
  individuals 
  never 
  fly, 
  but 
  

   these 
  are 
  exceptions 
  which 
  do 
  not 
  invalidate 
  the 
  general 
  rule. 
  That 
  

   they 
  are 
  not 
  habitually 
  sedentary 
  in 
  any 
  known 
  locality, 
  as 
  A. 
  american- 
  

   wm 
  is, 
  is 
  certainly 
  a 
  fact 
  that 
  cannot 
  be 
  denied. 
  

  

  FLIGHTS. 
  

  

  As 
  the 
  subject 
  of 
  flights 
  is 
  one 
  of 
  the 
  most 
  important 
  relating 
  to 
  the 
  

   history 
  and 
  habits 
  of 
  the 
  migratory 
  locusts, 
  the 
  Commission 
  has 
  taken 
  

   special 
  care 
  to 
  procure 
  all 
  the 
  data 
  possible 
  in 
  reference 
  to 
  the 
  flights 
  of 
  

   C. 
  spretus. 
  Our 
  success 
  in 
  this 
  respect 
  may 
  be 
  seen 
  by 
  referring 
  to 
  our 
  

   former 
  report. 
  That 
  we 
  have 
  exhausted 
  the 
  subject 
  we 
  do 
  not 
  contend, 
  

   but 
  we 
  may 
  fairly 
  claim 
  that 
  now 
  the 
  movements 
  of 
  C. 
  sprettis 
  are 
  better 
  

   known 
  to 
  the 
  world 
  than 
  those 
  of 
  any 
  other 
  locust 
  ; 
  and 
  although 
  we 
  

   do 
  not 
  wish 
  to 
  appear 
  as 
  boasting, 
  we 
  do 
  feel 
  as 
  we 
  think 
  a 
  justifiable 
  

   pride 
  in 
  asserting 
  the 
  fact. 
  

  

  