﻿CHARACTER 
  OP 
  THE 
  PERMANENT 
  BREEDING-GROUNDS. 
  69 
  

  

  €omo 
  better 
  acquainted 
  with 
  the 
  deserts 
  in 
  Africa, 
  so 
  long 
  and 
  bo 
  vaguely 
  confounded 
  

   under 
  the 
  name 
  of 
  "the 
  Desert 
  of 
  Sahara," 
  it 
  has 
  been 
  observed 
  that 
  in 
  this 
  conti- 
  

   nent, 
  towards 
  the 
  east, 
  savannas 
  and 
  pastures 
  are 
  found 
  situated 
  in 
  the 
  midst 
  of 
  

   naked 
  and 
  desert 
  tracts. 
  

  

  The 
  treeless 
  areas, 
  especially 
  when 
  elevated, 
  are 
  the 
  ones 
  the 
  locusts 
  

   appear 
  to 
  prefer, 
  aud 
  where, 
  as 
  a 
  general 
  thing, 
  we 
  find 
  their 
  homes, 
  one 
  

   species 
  preferring 
  the 
  more 
  elevated, 
  broken, 
  and 
  mountainous 
  sections, 
  

   -while 
  another 
  selects 
  the 
  lower 
  broad 
  barren 
  plains. 
  

  

  The 
  two 
  parts 
  of 
  the 
  Mediterranean 
  subregion 
  are 
  briefly 
  described 
  

   by 
  Wallace 
  as 
  follows 
  : 
  

  

  The 
  northern 
  section 
  is 
  almost 
  wholly 
  a 
  region 
  of 
  mountains 
  and 
  elevated 
  plateaus. 
  

   On 
  the 
  west, 
  Spain 
  is 
  mainly 
  a 
  table-land 
  of 
  more 
  than 
  2,000 
  feet 
  elevation, 
  deeply 
  

   penetrated 
  by 
  extensive 
  valleys 
  and 
  rising 
  into 
  lofty 
  mountain 
  chains. 
  Italy, 
  Corsica, 
  

   Sardinia, 
  and 
  Sicily 
  are 
  all 
  very 
  mountainous, 
  and 
  much 
  of 
  their 
  surface 
  considerably 
  

   elevated. 
  Earther 
  east 
  we 
  have 
  all 
  European 
  Turkey 
  and 
  Greece, 
  a 
  mountain 
  region, 
  

   with 
  a 
  comparatively 
  small 
  extent 
  of 
  level 
  plain. 
  

  

  Asia 
  Minor 
  to 
  the 
  Caspian 
  is 
  also 
  of 
  a 
  similar 
  character. 
  

  

  This 
  is 
  the 
  district 
  of 
  Caloptenus 
  italicus, 
  in 
  some 
  part 
  of 
  which 
  it 
  is 
  

   to 
  be 
  found 
  every 
  year 
  in 
  greater 
  or 
  less 
  abundance 
  and 
  more 
  or 
  less 
  mi- 
  

   gratory. 
  The 
  exact 
  limits 
  of 
  its 
  permanent 
  distribution, 
  and 
  whether 
  it 
  

   is 
  essentially 
  migratory 
  within 
  these 
  limits, 
  are 
  facts 
  which 
  do 
  not 
  appear 
  

   to 
  have 
  been 
  satisfactorily 
  ascertained 
  by 
  European 
  entomologists. 
  

  

  The 
  character 
  of 
  this 
  region 
  presents, 
  in 
  many 
  respects, 
  a 
  striking 
  sim- 
  

   ilarity 
  to 
  the 
  home 
  of 
  the 
  Rocky 
  Mountain 
  locust. 
  Here 
  is 
  an 
  elevated 
  

   region, 
  consisting 
  of 
  mountain 
  ranges 
  and 
  peaks 
  rising 
  to 
  the 
  height 
  of 
  

   ten, 
  twelve, 
  and 
  even 
  fourteen 
  thousand 
  feet 
  above 
  the 
  sea, 
  with 
  extensive 
  

   intervening 
  treeless 
  plateaus 
  elevated 
  from 
  four 
  to 
  six 
  thousand 
  feet 
  

   above 
  the 
  sea. 
  The 
  broad 
  mountain 
  ranges 
  have 
  their 
  sides 
  gashed 
  by 
  

   narrow 
  valleys, 
  whose 
  slopes 
  are 
  usually 
  treeless, 
  and 
  grassy 
  at 
  least 
  on 
  

   the 
  lower 
  portion. 
  A 
  laek 
  of 
  arboreal 
  vegetation, 
  except 
  in 
  the 
  heavier 
  

   mountain 
  masses, 
  is 
  a 
  marked 
  characteristic. 
  The 
  mountain 
  area 
  is 
  bor- 
  

   dered 
  on 
  its 
  eastern 
  flank 
  by 
  a 
  broad, 
  treeless 
  plain, 
  reaching 
  from 
  the 
  

   northern 
  lake 
  region 
  of 
  British 
  America 
  to 
  Mexico 
  and 
  extending 
  eastward 
  

   to 
  the 
  Missouri, 
  its 
  western 
  border 
  having 
  an 
  average 
  elevation 
  of 
  four 
  

   thousand 
  feet 
  and 
  sloping 
  eastward 
  at 
  the 
  rate 
  of 
  five 
  to 
  ten 
  feet 
  per 
  mile. 
  

  

  That 
  these 
  two 
  districts, 
  resembling 
  each 
  other 
  so 
  much 
  in 
  general 
  

   (character, 
  should 
  be 
  the 
  homes 
  of 
  two 
  migratory 
  locusts 
  so 
  closely 
  allied 
  

   as 
  to 
  belong 
  to 
  the 
  same 
  genus 
  cannot 
  be 
  accidental, 
  but 
  results 
  from 
  

   some 
  law 
  of 
  Acridian 
  life 
  which 
  has 
  not 
  yet 
  been 
  discovered. 
  To 
  attempt 
  

   its 
  solution 
  would 
  carry 
  us 
  back 
  into 
  the 
  history 
  of 
  the 
  climatic 
  changes 
  

   of 
  the 
  country, 
  the 
  vexed 
  question 
  of 
  specific 
  evolution, 
  and 
  into 
  an 
  ex- 
  

   amination 
  of 
  the 
  more 
  recent 
  geological 
  changes. 
  

  

  The 
  native 
  habitat 
  of 
  the 
  migratory 
  locust, 
  P. 
  migratorivs, 
  as 
  we 
  have 
  

   .already 
  seen, 
  consists 
  chiefly 
  of 
  more 
  or 
  less 
  elevated 
  grassy 
  plains, 
  usu- 
  

   ally 
  called 
  steppes, 
  resembling 
  in 
  some 
  respects 
  the 
  treeless 
  plains 
  of 
  the 
  

   west 
  j 
  in 
  other 
  words, 
  the 
  great 
  pasture 
  lands 
  of 
  Western 
  Asia 
  and 
  

   Eastern 
  Europe, 
  the 
  ancient 
  Scythian 
  hive, 
  and 
  the 
  present 
  home 
  of 
  the 
  

  

  