﻿the 
  Hessian 
  Fly. 
  331 
  

  

  which 
  had 
  but 
  one 
  blade, 
  or 
  at 
  the 
  most 
  three, 
  varying 
  

   in 
  length 
  from 
  an 
  inch 
  and 
  a 
  half 
  to 
  three 
  inches 
  high, 
  

   showing 
  that 
  they 
  were 
  of 
  very 
  recent 
  growth. 
  I 
  fomid 
  

   eggs 
  on 
  21 
  of 
  them, 
  all 
  laid 
  on 
  the 
  youngest 
  or 
  last 
  

   developed 
  leaf 
  ; 
  these 
  I 
  subjected 
  to 
  a 
  more 
  minute 
  

   examination 
  on 
  reaching 
  home 
  ; 
  the 
  total 
  number 
  of 
  

   eggs 
  being 
  113, 
  or 
  an 
  average 
  of 
  5 
  to 
  each 
  self-sown 
  

   plant, 
  the 
  actual 
  numbers 
  varying 
  from 
  2 
  up 
  to 
  12 
  on 
  a 
  

   leaf. 
  Of 
  the 
  100 
  plants 
  of 
  " 
  aftergrowth," 
  most 
  of 
  them 
  

   6 
  to 
  9 
  in. 
  high, 
  and 
  having 
  4 
  to 
  6 
  leaves, 
  only 
  12 
  had 
  

   been 
  attacked 
  ; 
  the 
  number 
  of 
  eggs 
  laid 
  was 
  84, 
  or 
  an 
  

   average 
  of 
  7 
  to 
  each 
  plant, 
  showing 
  the 
  marvellous 
  

   instinct 
  (or 
  whatever 
  else 
  we 
  may 
  term 
  it) 
  of 
  the 
  fly, 
  

   which, 
  in 
  the 
  case 
  of 
  the 
  delicate 
  self-sown 
  plant, 
  only 
  

   laid 
  5 
  to 
  each, 
  but 
  seem 
  to 
  know 
  that 
  the 
  stronger 
  after 
  - 
  

   groiDth 
  was 
  capable 
  of 
  sustaining 
  more 
  ; 
  the 
  number 
  of 
  

   eggs 
  laid 
  varied 
  from 
  2 
  to 
  20. 
  On 
  9 
  these 
  were 
  laid 
  on 
  

   the 
  last 
  developed 
  leaf, 
  and 
  on 
  the 
  other 
  3 
  the 
  eggs 
  were 
  

   divided, 
  and 
  laid 
  on 
  the 
  last 
  and 
  preceding 
  leaf 
  : 
  

   leading 
  me 
  to 
  think 
  that 
  two 
  flies 
  had 
  visited 
  these 
  three 
  

   plants. 
  Most 
  of 
  these 
  eggs 
  hatched 
  in 
  less 
  than 
  a 
  week. 
  

  

  On 
  Sept. 
  22nd, 
  1888, 
  I 
  found 
  great 
  numbers 
  of 
  eggs 
  

   on 
  both 
  self-sown 
  and 
  aftergrowth 
  barley 
  around 
  Stroud, 
  

   Gloucestershire, 
  where 
  I 
  also 
  found 
  puparia 
  in 
  the 
  stubble, 
  

   and 
  great 
  numbers 
  in 
  the 
  wheat 
  ; 
  in 
  fact, 
  in 
  every 
  barley 
  

   and 
  wheat 
  field 
  which 
  I 
  examined 
  around 
  Stroud 
  during 
  

   a 
  fortnight's 
  visit 
  to 
  Mr. 
  Thos. 
  Lancaster, 
  of 
  Bownham 
  

   House, 
  I 
  found 
  eggs 
  and 
  puparia 
  in 
  the 
  greatest 
  abun- 
  

   dance, 
  besides 
  capturing 
  a 
  number 
  of 
  specimens 
  of 
  the 
  

   male 
  Hessian 
  Fly 
  on 
  the 
  windows. 
  This 
  is 
  the 
  first 
  

   time 
  "the 
  pest" 
  had 
  been 
  reported 
  from 
  the 
  West 
  of 
  

   England, 
  though 
  no 
  doubt 
  it 
  had 
  been 
  firmly 
  established 
  

   there, 
  as 
  I 
  am 
  inclined 
  to 
  think 
  it 
  has 
  been 
  all 
  over 
  the 
  

   country, 
  for 
  some 
  time 
  ; 
  and 
  if 
  farmers 
  could 
  be 
  persuaded 
  

   to 
  search 
  for 
  it, 
  I 
  think 
  it 
  would 
  be 
  found 
  all 
  over 
  Eng- 
  

   land 
  and 
  Scotland, 
  and 
  in 
  all 
  probability 
  in 
  Ireland 
  too. 
  

  

  As 
  it 
  would 
  be 
  impossible 
  from 
  owf-door 
  observations 
  

   to 
  determine 
  the 
  number 
  of 
  eggs 
  a 
  female 
  fly 
  is 
  capable 
  

   of 
  laying, 
  we 
  must 
  fall 
  back 
  upon 
  experiments 
  conducted 
  

   somewdiat 
  under 
  difficulties 
  and 
  artificial 
  circumstances, 
  

   owing 
  to 
  the 
  surroundings 
  of 
  a 
  small 
  London 
  garden 
  

   not 
  being 
  quite 
  so 
  countrified 
  as 
  we 
  could 
  wish. 
  

  

  Erom 
  puparia 
  which 
  I 
  collected 
  on 
  Aug. 
  5th 
  and 
  8th, 
  

   1887, 
  I 
  bred 
  a 
  large 
  number 
  of 
  male 
  and 
  female 
  flies, 
  

  

  