﻿24 
  EEPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  undoubtedly 
  lias 
  presented 
  itself 
  to 
  the 
  minds 
  of 
  more 
  than 
  one 
  ento- 
  

   mologist 
  and 
  tiller 
  of 
  the 
  soil, 
  and 
  is 
  worthy 
  of 
  consideration 
  in 
  this 
  

   connection. 
  Before 
  discussing 
  it, 
  however, 
  let 
  me 
  give 
  a 
  short 
  descrix)- 
  

   tion 
  of 
  the 
  ijreferences 
  of 
  climate, 
  altitude, 
  vegetation, 
  surface 
  configu- 
  

   ration, 
  &c., 
  that 
  this 
  particular 
  species 
  of 
  locust 
  possesses 
  in 
  comparison 
  

   with 
  that 
  chosen 
  by 
  others. 
  

  

  If 
  we 
  run 
  our 
  eyes 
  over 
  the 
  map 
  of 
  North 
  America 
  and 
  set 
  aside 
  all 
  

   that 
  portion 
  contained 
  between 
  the 
  meridians 
  103° 
  and 
  117^ 
  west 
  of 
  

   Greenwich, 
  and 
  from 
  the 
  parallels 
  of 
  latitude 
  40^ 
  to 
  53^, 
  we 
  have 
  the 
  

   permanent 
  home 
  of 
  this 
  insect 
  pretty 
  well 
  before 
  us. 
  It 
  is 
  all 
  consider- 
  

   ably 
  elevated 
  above 
  the 
  surrounding 
  country, 
  treeless 
  over 
  the 
  greater 
  

   portion, 
  and 
  also 
  arid, 
  thus 
  agreeing 
  to 
  some 
  extent 
  with 
  the 
  locust-in- 
  

   habited 
  areas 
  of 
  Eastern 
  Europe, 
  Northern 
  Africa, 
  Western 
  and 
  South- 
  

   ern 
  Asia, 
  Central 
  Australia, 
  and 
  portions 
  of 
  Central 
  and 
  South 
  America. 
  

   Now, 
  what 
  is 
  there 
  in 
  these 
  peculiar 
  combinations 
  of 
  surface 
  and 
  cli- 
  

   mate 
  and 
  elevation 
  that 
  should 
  produce 
  the 
  unwonted 
  increase 
  in 
  num- 
  

   bers 
  of 
  a 
  few 
  particular 
  species 
  of 
  widely 
  different 
  locusts 
  ? 
  As 
  we 
  are 
  

   already 
  aware, 
  all 
  these 
  insects 
  become 
  exceedingly 
  numerous 
  at 
  inter- 
  

   vals, 
  and 
  at 
  such 
  times 
  leave 
  their 
  breediog 
  grounds, 
  or, 
  more 
  properly 
  

   speaking, 
  their 
  native 
  habitats, 
  and 
  fall 
  upon 
  the 
  adjoining 
  fertile 
  

   country, 
  where 
  they 
  cause 
  great 
  depredation, 
  and 
  in 
  many 
  instances 
  

   even 
  pestilence 
  and 
  famine. 
  That 
  this 
  great 
  increase 
  is 
  in 
  some 
  way 
  

   connected 
  with 
  their 
  migratory 
  habits 
  we 
  know, 
  but 
  just 
  how 
  it 
  was 
  

   brought 
  about 
  in 
  the 
  first 
  place 
  we 
  cannot 
  say. 
  As 
  shown 
  in 
  one 
  of 
  

   the 
  reports 
  of 
  the 
  Commission, 
  these 
  invasions, 
  id 
  est, 
  the 
  general 
  inva- 
  

   sions 
  of 
  tbe 
  entire 
  country 
  subject 
  to 
  their 
  visits, 
  appear 
  to 
  follow 
  at 
  in- 
  

   tervals 
  of 
  about 
  eleven 
  years. 
  

  

  The 
  reports 
  of 
  the 
  Commission 
  which 
  have 
  already 
  appeared 
  have 
  so 
  

   thoroughly 
  described 
  the 
  nature 
  and 
  habits 
  of 
  this 
  locust 
  that 
  I 
  need 
  

   not 
  dwell 
  upon 
  its 
  natural 
  history 
  or 
  mode 
  of 
  migrating. 
  That 
  it 
  is 
  thor- 
  

   oughly 
  migratory 
  by 
  nature 
  cannot 
  be 
  doubted; 
  for, 
  at 
  almost 
  any 
  

   I)oint 
  in 
  the 
  Permanent 
  Eegion 
  during 
  the 
  months 
  of 
  July, 
  August, 
  and 
  

   September, 
  on 
  fine 
  sunshiny 
  days, 
  a 
  few 
  of 
  these 
  insects 
  can 
  be 
  seen 
  on 
  

   the 
  move. 
  Even 
  a 
  single 
  family 
  or 
  the 
  pro.^eny 
  of 
  a 
  single 
  female 
  will 
  

   move 
  from 
  the 
  locality 
  where 
  it 
  hatched 
  to 
  some 
  other 
  point 
  in 
  this 
  

   native 
  habitat 
  or 
  adjaceiit 
  to 
  it. 
  

  

  If 
  we 
  reflect 
  for 
  a 
  moment 
  as 
  to 
  the 
  surface 
  configuration 
  of 
  the 
  different 
  

   countries 
  from 
  which 
  at 
  times 
  invading 
  hordes 
  of 
  locusts 
  come, 
  we 
  shall 
  

   notice 
  that 
  they 
  are 
  all 
  pretty 
  much 
  alike, 
  and 
  that 
  they 
  are 
  also, 
  as 
  a 
  

   rule, 
  destitute 
  of 
  timber 
  and 
  rank 
  vegetation 
  of 
  any 
  kind. 
  They 
  are 
  all 
  

   more 
  or 
  less 
  elevated 
  plateaus 
  or 
  table-lands, 
  partially 
  clothed 
  with 
  

   bunch 
  grasses 
  and 
  dwarfed 
  shrubs, 
  which 
  grow 
  in 
  clusters. 
  The 
  air 
  is 
  

   dry 
  and 
  bracing 
  in 
  its 
  nature, 
  and 
  the 
  winds 
  which 
  sweep 
  over 
  them 
  are 
  

   brisk. 
  Taking 
  into 
  consideration 
  these 
  peculiarities 
  of 
  the 
  various 
  lo- 
  

   cust 
  countries, 
  it 
  strikes 
  us 
  that 
  only 
  in 
  a 
  country 
  of 
  such 
  a 
  character 
  can 
  

   swarms 
  of 
  locusts 
  originate 
  and 
  continue 
  to 
  exist 
  in 
  uncommonly 
  great 
  

  

  