﻿632 
  REPOKT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  of 
  the 
  wings 
  and 
  straightening 
  of 
  the 
  legs 
  of 
  the 
  perfect 
  insect, 
  occupies 
  

   less 
  than 
  three 
  quarters 
  of 
  an 
  hour 
  and 
  sometimes 
  but 
  half 
  an 
  hour. 
  It 
  

   takes 
  place 
  most 
  frequently 
  during 
  the 
  warmer 
  hours 
  of 
  the 
  morning, 
  

   and 
  within 
  an 
  hour 
  after 
  the 
  wings 
  are 
  once 
  in 
  position 
  the 
  parts 
  have 
  

   become 
  sufficiently 
  dry 
  and 
  stiffened 
  to 
  enable 
  the 
  insect 
  to 
  move 
  about 
  

   with 
  ease, 
  and 
  m 
  another 
  hour, 
  with 
  appetite 
  sharpened 
  by 
  long 
  fast, 
  it 
  

   joins 
  its 
  voracious 
  comrades 
  and 
  tries 
  its 
  new 
  jaws. 
  The 
  molting 
  period, 
  

   especially 
  the 
  last, 
  is 
  a 
  very 
  critical 
  one, 
  and 
  during 
  the 
  helplessness 
  

   that 
  belongs 
  to 
  it 
  the 
  unfortunate 
  locust 
  falls 
  a 
  prey 
  to 
  many 
  enemies 
  

   which 
  otherwise 
  would 
  not 
  molest 
  it, 
  and 
  not 
  unfrequently 
  to 
  the 
  

   voracity 
  of 
  the 
  more 
  active 
  individuals 
  of 
  its 
  own 
  species. 
  — 
  (Riley's 
  

   Eighth 
  Eeport.) 
  

  

  The 
  egg 
  (Plate 
  LXII, 
  Fig. 
  1, 
  c) 
  is 
  curved, 
  cylindrical, 
  .21 
  inch 
  (5-J 
  milli- 
  

   meters) 
  in 
  length, 
  more 
  pointed 
  at 
  the 
  posterior 
  than 
  the 
  anterior 
  end. 
  

   The 
  posterior 
  end 
  is 
  contracted 
  just 
  before 
  the 
  extreme 
  tip, 
  which 
  is 
  

   smooth, 
  the 
  more 
  or 
  less 
  regular 
  pits 
  which 
  cover 
  the 
  chorion, 
  or 
  egg- 
  

   shell, 
  being 
  here 
  obsolete. 
  I 
  have 
  been 
  unable 
  to 
  discover 
  any 
  micropyle, 
  

   or 
  passage 
  for 
  the 
  spermatozoa. 
  The 
  posterior 
  end 
  points 
  downward 
  in 
  

   the 
  egg-moss, 
  so 
  that 
  the 
  exit 
  of 
  the 
  young 
  locust 
  from 
  the 
  anterior 
  end 
  

   is 
  thus 
  rendered 
  easier. 
  Although 
  I 
  have 
  not 
  seen 
  the 
  larva 
  actually 
  

   burst 
  Its 
  way 
  out 
  of 
  the 
  egg, 
  yet 
  on 
  the 
  examination 
  of 
  between 
  fifteen 
  

   and 
  twenty 
  deserted 
  eggshells, 
  I 
  have, 
  without 
  an 
  exception, 
  noticed 
  in 
  

   them 
  one, 
  more 
  usually 
  two, 
  slits 
  extending 
  from 
  the 
  headend 
  to 
  the 
  

   middle 
  of 
  the 
  egg. 
  The 
  egg-shell 
  is 
  without 
  doubt 
  burst 
  open 
  by 
  the 
  

   pitfflng 
  out 
  or 
  expansion 
  of 
  the 
  membrane 
  connecting 
  the 
  head 
  and 
  pro- 
  

   thorax, 
  just 
  as 
  the 
  common 
  house-fly 
  or 
  'flesh-fly 
  bursts 
  off 
  the 
  end 
  of 
  

   its 
  pupa-case 
  by 
  the 
  puffing 
  out 
  of 
  the 
  front 
  of 
  the 
  head. 
  I 
  have 
  seen 
  

   the 
  embryo 
  make 
  its 
  exit 
  in 
  two 
  or 
  three 
  instances. 
  In 
  one 
  case 
  I 
  saw 
  

   a 
  large 
  piece 
  of 
  the 
  egg-shell 
  (chorion) 
  fly 
  off 
  from 
  in 
  front 
  of 
  the 
  face 
  

   while 
  the 
  face 
  of 
  the 
  embryo 
  puffed 
  slightly 
  out, 
  and 
  in 
  another 
  instance 
  

   the 
  whole 
  anterior 
  end 
  of 
  the 
  shell 
  came 
  off. 
  In 
  the 
  locust 
  I 
  have 
  ob- 
  

   served, 
  as 
  will 
  be 
  seen 
  farther 
  on, 
  that 
  the 
  amnion 
  is 
  ruptured 
  by 
  the 
  

   forcible 
  expansion 
  of 
  the 
  membrane 
  behind 
  the 
  head, 
  the 
  larvae 
  before 
  

   walking 
  lying 
  on 
  their 
  backs 
  or 
  sides 
  and 
  forcing 
  this 
  membrane 
  out- 
  

   ward. 
  This 
  action 
  probably 
  begins 
  before 
  the 
  shell 
  is 
  burst 
  and 
  seems 
  

   amply 
  sufficient 
  to 
  burst 
  the 
  brittle 
  chorion, 
  which 
  is 
  easily 
  broken 
  and 
  

   peeled 
  off 
  by 
  rubbing 
  the 
  egg 
  between 
  the 
  fingers, 
  leaving 
  the 
  serous 
  

   membrane 
  beneath. 
  The 
  pressure 
  thus 
  exerted 
  must 
  be 
  a 
  lateral 
  one, 
  

   and 
  sufficient 
  to 
  rupture 
  the 
  chorion. 
  

  

  In 
  his 
  ninth 
  report 
  on 
  the 
  injurious 
  insects 
  of 
  Missouri, 
  Professor 
  Eiley 
  

   maintains 
  that 
  besides 
  " 
  a 
  continuation 
  of 
  undulating 
  contractions 
  and 
  

   expansions 
  of 
  the 
  body," 
  the 
  tips 
  of 
  the 
  jaws 
  and 
  " 
  sharp 
  tips 
  of 
  the 
  

   hind 
  tibial 
  spines," 
  the 
  shell 
  is 
  ruptured, 
  and 
  then 
  " 
  splits 
  up 
  to 
  the 
  

   eyes 
  or 
  beyond, 
  by 
  the 
  swelling 
  of 
  the 
  head." 
  I 
  think 
  the 
  swelling 
  of 
  

   the 
  space 
  between 
  the 
  head 
  and 
  thorax 
  is 
  sufficient 
  to 
  accomplish 
  the 
  

   mixture 
  of 
  the 
  shell. 
  It 
  may 
  be 
  objected 
  to 
  Mr. 
  Eiley's 
  account 
  of 
  the 
  

   supposed 
  action 
  of 
  the 
  jaws 
  and 
  spines 
  that, 
  as 
  may 
  be 
  seen 
  by 
  my 
  Fig. 
  2, 
  

   the 
  position 
  of 
  the 
  legs 
  is 
  such 
  that 
  the 
  tibial 
  spines 
  do 
  not 
  point 
  out- 
  

   ward, 
  the 
  tibise 
  being 
  placed 
  between 
  the 
  femora, 
  and 
  the 
  legs 
  are 
  not 
  

   displaced 
  until 
  after 
  the 
  amnion 
  is 
  shed. 
  Moreover 
  the 
  spines 
  are 
  soft 
  

   and 
  flabby, 
  as 
  well 
  as 
  the 
  legs 
  ; 
  besides 
  this 
  the 
  legs 
  and 
  the 
  entire 
  body 
  

   are 
  covered 
  by 
  the 
  amnion, 
  the 
  tibii^e 
  being 
  smooth. 
  Did 
  the 
  spines 
  saw 
  

   through 
  both 
  the 
  chorion 
  and 
  serous 
  membrane, 
  the 
  amnion 
  would, 
  of 
  

   course, 
  be 
  ruptured. 
  I 
  also 
  do 
  not 
  think 
  that 
  the 
  jaws 
  would 
  be 
  available 
  

   until 
  after 
  the 
  amnion 
  has 
  been 
  cast. 
  That 
  the 
  jaws 
  are 
  not 
  moved 
  out 
  of 
  

   their 
  place 
  until 
  after 
  the 
  embryo 
  leaves 
  its 
  egg-shell 
  and 
  throws 
  off 
  its 
  

  

  