﻿PACKARD.l 
  THE 
  LOCUST 
  IN 
  COLORADO. 
  595 
  

  

  on 
  the 
  fallen 
  trees 
  by 
  the 
  side 
  of 
  a 
  brook, 
  while 
  the 
  adults 
  were 
  flying^ 
  

   perhaps 
  1,000 
  feet 
  overhead. 
  On 
  the 
  extreme 
  summit 
  (elevation 
  14,147, 
  

   Parry's 
  estimate 
  14,216, 
  feet), 
  the 
  locusts 
  were 
  flying, 
  though 
  not 
  in 
  great 
  

   abundance, 
  at 
  least 
  500 
  feet 
  above 
  the 
  top; 
  some 
  fell 
  with 
  a 
  thud 
  on 
  the 
  

   rocks 
  and 
  seemed 
  paralyzed 
  or 
  were 
  found 
  benumbed 
  on 
  the 
  snow. 
  I 
  

   did 
  not 
  notice 
  that 
  tbey 
  were 
  flying 
  in 
  any 
  determinate 
  direction, 
  but 
  

   as 
  vast 
  numbers 
  of 
  a 
  green 
  Haltica 
  covered 
  the 
  low 
  alpine 
  vegetation, 
  

   I 
  judge 
  tbat 
  as 
  these 
  had 
  evidently 
  been 
  borne 
  up 
  by 
  currents 
  of 
  wind 
  

   from 
  the 
  plains 
  below, 
  the 
  locusts 
  had 
  been 
  carried 
  up 
  in 
  a 
  similar 
  

   manner, 
  especially 
  as 
  they 
  were 
  more 
  abundant 
  on 
  that 
  day 
  at 
  an 
  eleva- 
  

   tion 
  of 
  8,000 
  to 
  9,000 
  feet. 
  That, 
  however, 
  even 
  at 
  this 
  latter 
  elevation, 
  

   the 
  winged 
  locusts 
  had 
  probably 
  come 
  from 
  the 
  plains 
  east 
  of 
  the 
  mount- 
  

   ains 
  seems 
  evident, 
  as 
  the 
  young 
  born 
  at 
  this 
  altitude 
  had 
  not 
  yet 
  ac- 
  

   quired 
  their 
  wings. 
  Indeed, 
  it 
  seems 
  to 
  me 
  exceedingly 
  doubtful 
  whether 
  

   those 
  born 
  above 
  an 
  altitude 
  of 
  8,000 
  or 
  9,000 
  feet 
  arrive 
  at 
  maturity 
  if 
  

   they 
  do 
  acquire 
  wings; 
  their 
  flight 
  is 
  only 
  local, 
  from 
  one 
  canon 
  to 
  

   another. 
  It 
  seems 
  evident 
  that 
  the 
  vast 
  swarms 
  which 
  appear 
  occa- 
  

   sionally 
  must 
  have 
  been 
  hatched 
  on 
  the 
  plains 
  to 
  the 
  west 
  and 
  northwest, 
  

   at 
  an 
  altitude 
  of 
  5,000 
  to 
  7,000 
  feet. 
  

  

  As 
  regards 
  the 
  inferences 
  to 
  be 
  drawn 
  from 
  my 
  own 
  observations 
  in 
  

   Colorado, 
  which 
  were 
  made 
  between 
  June 
  27 
  and 
  July 
  19, 
  namely, 
  after 
  

   the 
  spring 
  brood 
  had 
  taken 
  flight 
  and 
  before 
  the 
  late 
  summer 
  swarms 
  

   had 
  arrived 
  on 
  the 
  plains, 
  I 
  would 
  state: 
  

  

  1; 
  That 
  in 
  the 
  cafions 
  and 
  mountains 
  above 
  an 
  elevation 
  of 
  about 
  

   8,000 
  feet 
  the 
  young 
  were 
  too 
  few 
  in 
  number 
  and 
  too 
  late 
  in 
  their 
  devel- 
  

   opment 
  to 
  supply 
  the 
  material 
  for 
  the 
  swarms 
  that 
  visited 
  the 
  plains 
  

   about 
  Denver 
  in 
  August. 
  

  

  2. 
  The 
  grasshoppers 
  seen 
  by 
  me 
  sailing 
  in 
  the 
  air 
  between 
  about 
  0,000 
  

   and 
  9,000 
  feet 
  elevation 
  were 
  probably 
  <lerived 
  from 
  the 
  April 
  and 
  May 
  

   broods 
  of 
  the 
  plains 
  about 
  Denver, 
  east 
  of 
  the 
  foot-hills 
  of 
  the 
  Rocky 
  

   Mountain 
  Eange. 
  

  

  3. 
  The 
  August 
  swarms 
  which 
  spread 
  over 
  the 
  plains 
  about 
  Denver 
  

   and 
  the 
  country 
  north 
  and 
  south, 
  within 
  a 
  hundred 
  miles 
  or 
  so, 
  origi- 
  

   nated 
  in 
  Colorado, 
  but 
  probably 
  not 
  the 
  adjacent 
  Territories, 
  and 
  were 
  

   derived 
  from 
  those 
  bred 
  on 
  the 
  plains 
  about 
  Denver 
  directly 
  east 
  of 
  the 
  

   mountains, 
  which 
  were 
  borne 
  aloft 
  in 
  June, 
  and 
  then 
  collected 
  in 
  large 
  

   swarms 
  and 
  migrated 
  back, 
  borne 
  by 
  westerly 
  winds, 
  later 
  in 
  the 
  sea- 
  

   son, 
  to 
  find 
  suitable 
  places 
  for 
  laying 
  their 
  eggs. 
  It 
  is 
  not 
  improbable 
  

   that 
  the 
  earliest 
  local 
  swarms, 
  such 
  as 
  devastated 
  the 
  plains 
  of 
  Colorado, 
  

   bred 
  in 
  the 
  plains 
  about 
  Denver, 
  and 
  gathered 
  for 
  about 
  a 
  month 
  in 
  the 
  

   lower 
  portion 
  of 
  the 
  mountain 
  valleys 
  into 
  the 
  compact 
  and 
  well-organ- 
  

   ized 
  swarm 
  which, 
  to 
  some 
  extent, 
  devastated 
  the 
  Colorado 
  Plains. 
  

   Undoubtedly 
  the 
  sexual 
  instinct 
  leads 
  large 
  swarms, 
  bred 
  during 
  favor- 
  

   able 
  seasons, 
  to 
  migrate 
  in 
  search 
  of 
  broad 
  plains 
  which 
  afford 
  the 
  proper 
  

   conditions 
  for 
  the 
  deposition 
  of 
  their 
  eggs 
  and 
  the 
  nourishment 
  of 
  their 
  

   young. 
  But 
  it 
  is 
  evident 
  that 
  the 
  parks 
  and 
  canons 
  of 
  the 
  Rocky 
  Mount- 
  

   ains 
  of 
  Colorado, 
  all 
  of 
  which 
  lie 
  above 
  an 
  altitude 
  of 
  7,000 
  feet, 
  pre- 
  

   sent 
  conditions 
  of 
  elevation, 
  climate, 
  extent 
  of 
  territory, 
  and 
  food 
  too 
  

   unfavorable 
  for 
  the 
  x>roduction 
  of 
  the 
  immense 
  swarms 
  which 
  at 
  long 
  

   intervals 
  devastate 
  the 
  Colorado 
  Plateau 
  and 
  portions 
  of 
  Kansas 
  and 
  

   adjoining 
  States. 
  It 
  is 
  most 
  probable, 
  however, 
  that 
  the 
  late 
  August 
  

   and 
  early 
  September 
  broods 
  of 
  locusts 
  noticed 
  by 
  Mr. 
  Byers 
  about 
  

   Denver 
  may 
  have 
  been 
  born 
  and 
  bred 
  during 
  exceptionally 
  dry 
  seasons 
  

   in 
  the 
  plains 
  of 
  Wyoming 
  and 
  Montana, 
  and 
  thus 
  appeared 
  in 
  Colorado 
  

   a 
  month 
  later 
  than 
  those 
  bred 
  east 
  of 
  the 
  mountains. 
  It 
  is 
  doubtful 
  if 
  

   the 
  young 
  individuals 
  (larvse) 
  which 
  I 
  saw 
  at 
  diftereut 
  elevations 
  up 
  to 
  

  

  