﻿the 
  Hessian 
  Fly. 
  333 
  

  

  On 
  Aug. 
  5th, 
  one 
  female 
  laid 
  80 
  eggs 
  on 
  one 
  leaf 
  2 
  in. 
  

   long, 
  and 
  another 
  100 
  in 
  a 
  small 
  phial- 
  

  

  Aug, 
  6th, 
  a 
  female 
  laid 
  58, 
  and 
  another 
  140 
  eggs. 
  

  

  On 
  the 
  same 
  date 
  I 
  placed 
  six 
  impregnated 
  females 
  in 
  

   separate 
  phials, 
  where 
  each 
  one 
  commenced 
  to 
  oviposit 
  

   freely, 
  placing 
  the 
  greatest 
  number 
  on 
  the 
  under 
  side 
  of 
  

   the 
  corks. 
  No. 
  1 
  laid 
  130 
  ; 
  No. 
  2, 
  125 
  ; 
  No. 
  3, 
  129 
  ; 
  

   No. 
  4, 
  114 
  ; 
  No. 
  5, 
  96 
  ; 
  and 
  No. 
  6, 
  70 
  eggs. 
  

  

  I 
  will 
  not 
  weary 
  you 
  with 
  further 
  details 
  of 
  oviposition, 
  

   as 
  those 
  I 
  have 
  given 
  show 
  that 
  the 
  female 
  Hessian 
  Fly 
  

   lays 
  from 
  100 
  to 
  150 
  eggs, 
  distributing 
  them 
  over 
  many 
  

   plants, 
  and 
  depositing 
  them 
  end 
  to 
  end 
  in 
  rows 
  of 
  

   3 
  to 
  10, 
  sometimes 
  side 
  by 
  side, 
  and 
  at 
  others 
  carelessly 
  

   in 
  clusters. 
  

  

  On 
  Sept. 
  13th, 
  1888, 
  1 
  dug 
  up 
  a 
  fresh 
  root 
  of 
  wild 
  oat- 
  

   grass 
  (Arrhenatherum 
  avenaceum), 
  and 
  re-set 
  it 
  in 
  a 
  pot 
  

   of 
  sandy 
  soil, 
  covering 
  it 
  over 
  with 
  a 
  cylinder 
  of 
  book- 
  

   muslin 
  ; 
  I 
  then 
  introduced 
  some 
  female 
  flies, 
  and 
  one 
  

   soon 
  settled 
  down 
  to 
  ovipositing 
  on 
  the 
  upper 
  surface 
  of 
  

   the 
  leaves 
  ; 
  but 
  I 
  noticed 
  a 
  peculiar 
  uneasy 
  movement 
  

   of 
  the 
  ovipositor, 
  as 
  though 
  the 
  fly 
  was 
  not 
  quite 
  satisfied 
  

   that 
  it 
  was 
  a 
  suitable 
  plant 
  ; 
  and 
  when 
  some 
  fresh 
  barley 
  

   leaves 
  were 
  introduced, 
  she 
  immediately 
  recognised 
  their 
  

   presence, 
  becoming 
  quite 
  excited 
  and 
  utterly 
  careless 
  in 
  

   her 
  hurry 
  to 
  lay 
  her 
  eggs, 
  most 
  of 
  which 
  were 
  in 
  clusters 
  

   or, 
  I 
  might 
  say, 
  lumps. 
  On 
  Oct, 
  14th 
  I 
  made 
  a 
  careful 
  

   examination 
  of 
  the 
  grass, 
  but 
  could 
  not 
  find 
  any 
  trace 
  of 
  

   larvse, 
  so 
  concluded 
  the 
  stem 
  was 
  too 
  hard 
  and 
  dry 
  for 
  

   them 
  to 
  subsist 
  on. 
  Prof. 
  C. 
  Lindeman, 
  of 
  Moscow, 
  has 
  

   found 
  the 
  puparia 
  on 
  Timothy-grass 
  (Phleimi 
  pratetise). 
  

  

  I 
  have 
  made 
  most 
  careful 
  microscopic 
  measurements 
  

   of 
  the 
  fresh-laid 
  egg, 
  which 
  is 
  "02 
  mm. 
  long 
  by 
  '008 
  

   broad 
  ; 
  it 
  is 
  rounded 
  at 
  both 
  ends, 
  of 
  a 
  pale 
  orange 
  

   colour, 
  with 
  reddish 
  dots 
  here 
  and 
  there, 
  making 
  it 
  very 
  

   easy 
  to 
  be 
  seen 
  in 
  the 
  ridges 
  of 
  the 
  young 
  barley-leaves; 
  

   this 
  colour 
  soon 
  changes 
  to 
  a 
  somewhat 
  darker 
  hue, 
  the 
  

   shell 
  becoming 
  so 
  transparent 
  on 
  the 
  third 
  day 
  that 
  the 
  

   movements 
  of 
  the 
  enclosed 
  larvas 
  can 
  be 
  distinctly 
  seen 
  ; 
  

   and 
  on 
  the 
  fourth 
  day 
  I 
  have 
  often 
  watched 
  them 
  making 
  

   muscular 
  efforts 
  to 
  burst 
  open 
  the 
  shell, 
  which 
  they 
  

   succeed 
  in 
  doing 
  after 
  three 
  or 
  four 
  hours' 
  work. 
  

  

  The 
  female 
  fly, 
  as 
  a 
  rule, 
  lays 
  her 
  eggs 
  with 
  the 
  head- 
  

   end 
  pointing 
  downwards 
  towards 
  the 
  main 
  stem, 
  so 
  that 
  

   when 
  the 
  tiny 
  larva 
  emerges 
  it 
  is 
  started 
  from 
  its 
  infancy 
  

  

  