﻿MODE 
  OF 
  EGG-LAYING. 
  211 
  

  

  some 
  doubt 
  whetlier 
  tlie 
  fly 
  liad 
  issued, 
  siiggestiug 
  tliat 
  it 
  miglit 
  be 
  tlie 
  

   l)arasite 
  that 
  bad 
  eaten 
  the 
  fly 
  and 
  come 
  forth, 
  as 
  the 
  time 
  appeared 
  to> 
  

   him 
  too 
  short, 
  Mr. 
  Hulick 
  at 
  once 
  planted 
  some 
  of 
  the 
  volunteer 
  wheat^ 
  

   still 
  containing 
  the 
  ''flaxseed," 
  in 
  close 
  jars, 
  and 
  — 
  

  

  Saw 
  many 
  of 
  the 
  flies 
  issue 
  ; 
  and, 
  more, 
  liad 
  eggs 
  laid 
  by 
  these 
  flies 
  on 
  the 
  same 
  

   wheat 
  in 
  October. 
  Mr. 
  Hulick 
  showed 
  these 
  flies 
  and 
  their 
  eggs 
  to 
  several 
  of 
  his 
  

   neighbors. 
  In 
  this 
  case 
  the 
  eggs 
  were 
  deposited 
  in 
  July, 
  the 
  flaxseed 
  state 
  assumed 
  

   in 
  September, 
  from 
  which 
  came 
  a 
  third 
  brood 
  of 
  flies 
  in 
  October. 
  This 
  is 
  certainly 
  a 
  

   very 
  important 
  matter, 
  as 
  it 
  shows 
  that 
  three 
  broods 
  are 
  possible 
  under 
  favorable 
  con- 
  

   ditions. 
  That 
  while 
  the 
  fall 
  flies 
  may, 
  nay 
  generally 
  must, 
  wait 
  till 
  September 
  to 
  

   deposit 
  eggs, 
  they 
  only 
  want 
  opportunity 
  to 
  breed 
  their 
  mischief 
  much 
  earlier, 
  even 
  

   in 
  July 
  or 
  August, 
  and 
  thus 
  propagate 
  a 
  late 
  brood 
  of 
  flies 
  which 
  will 
  be 
  in 
  readiness 
  

   for 
  even 
  the 
  latest 
  sown 
  wheat. 
  No 
  doubt, 
  too, 
  as 
  in 
  the 
  case 
  of 
  all 
  insects, 
  varying; 
  

   degrees 
  of 
  heat 
  or 
  cold 
  will 
  accelerate 
  or 
  retard 
  the 
  various 
  transformations. 
  (Lec- 
  

   ture, 
  &c., 
  p. 
  9.) 
  

  

  Mode 
  of 
  egg 
  laying 
  (see 
  Plate 
  IV, 
  e, 
  the 
  fly 
  of 
  its 
  natural 
  size 
  engaged 
  

   in 
  laying 
  its 
  eggs 
  on 
  the 
  leaf 
  of 
  wheat). 
  — 
  The 
  mode 
  of 
  oviposition 
  has 
  

   thus 
  been 
  described 
  by 
  Mr. 
  Herrick 
  : 
  

  

  The 
  eggs 
  are 
  laid 
  in 
  the 
  long 
  creases 
  or 
  furrows 
  of 
  the 
  upper 
  surface 
  of 
  the 
  leave® 
  

   (i. 
  €., 
  the 
  blade 
  or 
  strap-shaped 
  part) 
  of 
  the 
  young 
  wheat 
  plant. 
  While 
  depositing^ 
  

   her 
  eggs 
  the 
  insect 
  stands 
  with 
  her 
  head 
  towards 
  the 
  point 
  or 
  extremity 
  of 
  the 
  leaf^ 
  

   and 
  at 
  various 
  distances 
  between 
  the 
  point 
  and 
  where 
  the 
  leaf 
  joins 
  and 
  surrounds 
  

   the 
  stalk. 
  The 
  number 
  found 
  oh 
  a 
  single 
  leaf 
  varies 
  from 
  a 
  single 
  egg 
  up 
  to 
  thirty^ 
  

   or 
  even 
  more. 
  

  

  Professor 
  Cook 
  says 
  that 
  — 
  

  

  The 
  fly 
  very 
  rarely 
  lays 
  more 
  than 
  three 
  eggs 
  at 
  one 
  time 
  without 
  change 
  of 
  posi- 
  

   tion. 
  She 
  more 
  frequently 
  lays 
  two, 
  and 
  generally 
  but 
  one. 
  In 
  case 
  she 
  lays 
  but 
  on© 
  

   it 
  takes 
  less 
  than 
  a 
  quarter 
  of 
  a 
  minute, 
  and 
  less 
  than 
  half 
  a 
  miuute 
  to 
  lay 
  threOj, 
  

   when 
  they 
  are 
  all 
  laid 
  without 
  a 
  change 
  of 
  position 
  on 
  the 
  part 
  of 
  the 
  fly. 
  After 
  

   laying 
  she 
  seems 
  to 
  draw 
  in 
  her 
  ovipositor 
  soon 
  to 
  extend 
  it 
  again, 
  at 
  the 
  same 
  time 
  

   crowding 
  into 
  it 
  the 
  one, 
  two, 
  or 
  three 
  eggs 
  that 
  are 
  next 
  to 
  be 
  laid. 
  She 
  then 
  flie» 
  

   to 
  another 
  leaf, 
  alighting 
  usually, 
  not 
  always, 
  with 
  head 
  towards 
  the 
  end 
  of 
  the 
  leaf. 
  

   She 
  then 
  appears 
  to 
  wipe 
  the 
  eggs 
  otf 
  the 
  jointed 
  ovipositor. 
  She 
  really 
  crowds 
  the^ 
  

   egg 
  till 
  the 
  end 
  touches 
  the 
  leaf, 
  when 
  by 
  friction 
  of 
  the 
  leaf 
  and 
  adhesion 
  of 
  the 
  egg: 
  

   the 
  latter 
  is 
  held 
  fast 
  while 
  the 
  egg-tube 
  is 
  withdrawn. 
  If 
  the 
  second 
  and 
  third 
  are 
  

   to 
  be 
  laid 
  she 
  repeats 
  the 
  operation, 
  after 
  which 
  she 
  retracts 
  her 
  ovipositor, 
  restocks 
  

   it, 
  and 
  in 
  a 
  trice 
  is 
  depositing 
  the 
  fatal 
  germs 
  on 
  another 
  leaf. 
  I 
  say 
  usually 
  on 
  the- 
  

   upper 
  surface, 
  for 
  occasionally 
  eggs 
  are 
  laid 
  on 
  the 
  stalk, 
  and 
  sometimes 
  on 
  the 
  under 
  

   side 
  of 
  a 
  leaf. 
  I 
  have 
  observed 
  that 
  the 
  fly 
  often 
  makes 
  many 
  unsuccessful 
  eiforts 
  t©> 
  

   cause 
  the 
  egg 
  to 
  adhere 
  on 
  the 
  outer 
  face 
  of 
  the 
  leaf 
  Itefore 
  she 
  succeeds. 
  I 
  have 
  seeia 
  

   a 
  fly 
  work 
  thus 
  for 
  two 
  minutes 
  before 
  success 
  crowned 
  her 
  eiibrts. 
  The 
  fly 
  may 
  thus> 
  

   learn 
  by 
  experience 
  that 
  it 
  is 
  easier 
  to 
  deposit 
  on 
  the 
  inner 
  or 
  upper 
  face 
  of 
  th© 
  

   blade, 
  and 
  so 
  generally 
  choose 
  that 
  surface. 
  We 
  shall 
  see, 
  too, 
  in 
  the 
  sequel, 
  that 
  it 
  

   is 
  better 
  for 
  the 
  prospective 
  maggot 
  that 
  the 
  egg 
  be 
  placed 
  on 
  the 
  upper 
  surface. 
  In 
  

   four 
  to 
  ten 
  days, 
  more 
  or 
  less, 
  as 
  the 
  weather 
  is 
  cool 
  or 
  warm, 
  the 
  eggs 
  hatch. 
  (Lec- 
  

   ture, 
  p. 
  7.) 
  

  

  Mr. 
  C. 
  Y. 
  Eiley 
  describes 
  as 
  follows 
  the 
  process 
  in 
  the 
  Kew 
  York 
  

   Tribune: 
  

  

  I 
  have 
  very 
  carefully 
  studied 
  the 
  oviposition 
  of 
  the 
  Hessian 
  Fly, 
  closely 
  observing; 
  

   the 
  female 
  in 
  the 
  act 
  on 
  several 
  occasions 
  ; 
  and 
  as 
  accurate 
  observations 
  on 
  this 
  point 
  

   are 
  not 
  easily 
  made, 
  I 
  herewith 
  transcribe 
  my 
  notes 
  of 
  several 
  years 
  ago 
  : 
  

  

  