﻿638 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  ruhrum 
  from 
  Essex 
  County, 
  Massachusetts, 
  a 
  slight 
  tendeucy 
  of 
  the 
  ab- 
  

   domen 
  to 
  become 
  notched, 
  and 
  I 
  should 
  not 
  be 
  surprised 
  to 
  find 
  inter- 
  

   mediate 
  links 
  connecting 
  the 
  variety 
  atlcmis 
  with 
  femurrubrum, 
  but 
  

   with 
  the 
  evidence 
  now 
  before 
  me, 
  especially 
  the 
  occurrence 
  in 
  California 
  

   of 
  diminutive 
  short-winged 
  male 
  spretus, 
  scarcely 
  distingui 
  shable 
  from 
  the 
  

   eastern 
  atlanis, 
  the 
  two 
  specimens 
  agreeing 
  well 
  in 
  the 
  form 
  of 
  the 
  ab- 
  

   dominal 
  tip. 
  I 
  am 
  inclined 
  to 
  the 
  belief 
  that 
  atlanis 
  is 
  simply 
  a 
  variety 
  

   of 
  spretus. 
  Speculating 
  on 
  the 
  origin 
  of 
  the 
  two 
  species, 
  I 
  should 
  con- 
  

   sider, 
  that 
  /ewmr-rM&rMm 
  being 
  on 
  the 
  whole 
  the 
  more 
  widespread 
  species, 
  

   that 
  spretus 
  originated 
  from 
  it 
  after 
  it 
  [femur-ruhrum) 
  hfld 
  attained 
  its 
  

   present 
  distribution, 
  and 
  that 
  spretus 
  assumed 
  its 
  larger 
  size 
  and 
  great 
  

   length 
  of 
  wing 
  on 
  the 
  hot 
  and 
  dry 
  central 
  plateau 
  of 
  the 
  Eocky 
  Moun- 
  

   tains. 
  

  

  Practically 
  considered 
  the 
  two 
  injurious 
  forms 
  are 
  the 
  gQuwmo, 
  spretus 
  

   and 
  the 
  gQiixxmo, 
  femur-riibrum. 
  It 
  is 
  the 
  latter 
  which 
  is 
  so 
  abundant 
  

   and 
  destructive 
  at 
  times 
  in 
  the 
  New 
  England 
  States 
  and 
  Canada. 
  

   Having 
  known 
  the 
  insect 
  so 
  well 
  for 
  twenty 
  years 
  in 
  Maine 
  and 
  New 
  

   Hampshire, 
  I 
  am 
  surprised 
  to 
  find 
  in 
  Mr. 
  Riley's 
  seventh 
  report 
  the 
  

   suggestion 
  that 
  the 
  femiir-rubrum 
  "had 
  been 
  confounded" 
  with 
  his 
  

   atlanis, 
  and 
  "had 
  played 
  the 
  part 
  of 
  a 
  migratory 
  locust 
  in 
  the 
  White 
  

   Mountain 
  region 
  of 
  Maine 
  and 
  New 
  Hampshire." 
  The 
  form 
  atlanis 
  is 
  

   a 
  comparatively 
  rare 
  one 
  in 
  New 
  England. 
  During 
  the 
  summer 
  of 
  1874:, 
  

   '75, 
  and 
  '76, 
  in 
  Massachusetts 
  at 
  least, 
  it 
  has 
  been 
  very 
  rarely 
  met 
  with, 
  

   compared 
  with 
  the 
  ordinary 
  red-legged 
  locust, 
  and 
  must 
  have 
  been 
  so 
  

   in 
  1864, 
  judging 
  by 
  the 
  labels 
  on 
  the 
  specimens 
  in 
  the 
  museum 
  of 
  the 
  

   Peabody 
  Academy 
  of 
  Science, 
  and 
  I 
  have 
  little 
  doubt 
  but 
  that 
  it 
  has 
  

   always 
  been 
  a 
  comparatively 
  scarce 
  insect, 
  while 
  the 
  genuine 
  /e>/mr- 
  

   riibrum 
  abounds 
  in 
  countless 
  numbers 
  each 
  summer 
  and 
  autumn 
  from 
  

   Maine 
  to 
  Massachusetts, 
  and 
  I 
  suiDpose 
  all 
  over 
  its 
  destructive 
  limits 
  as 
  

   laid 
  down 
  on 
  Map 
  II. 
  

  

  I 
  have 
  receivecl 
  a 
  male 
  and 
  female 
  of 
  C. 
  spretus, 
  var. 
  atlanis, 
  from 
  Mr. 
  

   Henry 
  Gillman, 
  of 
  Detroit, 
  who 
  collected 
  them 
  "near 
  Laughing 
  Pish 
  

   River, 
  Michigan,* 
  on 
  the 
  south 
  shore 
  of 
  Lake 
  Superior. 
  This 
  river 
  falls 
  

   into 
  Traine 
  Bay, 
  an 
  indentation 
  of 
  the 
  coast 
  to 
  the 
  eastward 
  of 
  Mar- 
  

   quette. 
  These 
  specimens 
  measured 
  thus, 
  from 
  head 
  to 
  tip 
  of 
  wings 
  when 
  

   folded, 
  male 
  1.08, 
  female 
  1.10 
  inches: 
  atlanis 
  from 
  Massachusetts, 
  male 
  

   1.02, 
  female 
  1.12 
  inches 
  ; 
  atlanis 
  from 
  Illinois, 
  male 
  0.92, 
  female 
  0.95 
  inch 
  ; 
  

   atlanis 
  from 
  California, 
  male 
  0.99 
  inch. 
  On 
  the 
  other 
  hand 
  a 
  male 
  G. 
  

   .spretus, 
  normal 
  form, 
  from 
  Iowa, 
  measured 
  1.30, 
  while 
  an 
  average 
  male 
  

   from 
  Colorado 
  was 
  1.34 
  inches 
  in 
  length. 
  Ten 
  specimens 
  of 
  Iowa 
  spretus, 
  

   the 
  offspring 
  of 
  emigrants 
  from 
  the 
  Rocky 
  Mountains, 
  were 
  slightly 
  

   smaller 
  and 
  considerably 
  darker 
  than 
  specimens 
  from 
  Missouri, 
  Kansas, 
  

   and 
  Colorado, 
  a]>proaching 
  slightly 
  but 
  perceptibly 
  var. 
  atlanis 
  and 
  

   femur-rubrum. 
  I 
  have 
  the 
  idea 
  that 
  if 
  the 
  normal 
  form 
  of 
  spretus 
  were 
  

   permanently 
  acclimated 
  in 
  the 
  Mississippi 
  Valley, 
  it 
  would 
  change 
  to 
  

   var. 
  atlanis. 
  

  

  I 
  should 
  add 
  that 
  the 
  conclusions 
  regarding 
  the 
  varietal 
  nature 
  I 
  

   have 
  above 
  stated 
  are 
  written 
  out 
  from 
  notes 
  made 
  two 
  years 
  since 
  

   after 
  careful 
  examinations, 
  and 
  in 
  2874, 
  and 
  again 
  in 
  1875, 
  while 
  I 
  have 
  

   at 
  the 
  present 
  time 
  of 
  writing 
  re-examined 
  the 
  subject 
  and 
  come 
  to 
  the 
  

   same 
  conclusion 
  as 
  I 
  held 
  in 
  1874. 
  

  

  DOES 
  THE 
  ROCKY 
  MOUNTAIN 
  LOCUST 
  INHABIT 
  THE 
  PACIFIC 
  COAST 
  ? 
  

  

  Prof. 
  0. 
  Thomas 
  remarks 
  as 
  follows 
  in 
  the 
  Zoology 
  of 
  Lieutenant 
  

   Wheeler's 
  Survey, 
  p. 
  892,- 
  1876, 
  concerning 
  the 
  westward 
  distribution 
  

  

  * 
  Riviere 
  aus 
  Poissous 
  qui 
  rit, 
  of 
  the 
  French 
  Voyageurs. 
  

  

  