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  XII. 
  The 
  life-history 
  of 
  the 
  Hessian 
  Fly, 
  Cecidomyia 
  

   destructor, 
  Say. 
  By 
  Feedeeick 
  Enock, 
  F.E.S. 
  

  

  [Eead 
  February 
  4th, 
  1891.J 
  

  

  Plate 
  XVI. 
  

  

  In 
  the 
  ' 
  Third 
  Keport 
  of 
  the 
  United 
  States 
  Entomological 
  

   Commission, 
  1882,' 
  there 
  is 
  a 
  long 
  paper 
  compiled 
  by 
  

   Dr. 
  A. 
  S. 
  Packard, 
  on 
  the 
  Hessian 
  Fly, 
  concluding 
  with 
  

   a 
  list 
  of 
  no 
  less 
  than 
  seventy-one 
  papers 
  and 
  articles 
  on 
  

   this 
  insect 
  ; 
  and 
  since 
  that 
  date 
  the 
  number 
  has 
  gone 
  on 
  

   increasing, 
  so 
  that 
  up 
  to 
  the 
  present 
  time 
  it 
  cannot 
  be 
  

   far 
  short 
  of 
  one 
  hundred 
  ! 
  This 
  being 
  so, 
  anyone 
  would 
  

   naturally 
  suppose 
  that 
  the 
  subject 
  had 
  been 
  thoroughly 
  

   worked 
  out, 
  with 
  every 
  detail 
  of 
  the 
  life-history 
  laid 
  bare, 
  

   until 
  nothing 
  more 
  could 
  be 
  learned 
  about 
  it 
  ; 
  and 
  I 
  dare 
  

   say 
  that 
  many 
  may 
  think 
  it 
  presumptuous 
  on 
  my 
  part 
  

   to 
  attempt 
  to 
  say 
  anything 
  new: 
  My 
  reason 
  for 
  bringing 
  

   this 
  matter 
  before 
  you 
  is 
  — 
  that 
  of 
  all 
  those 
  who 
  have 
  

   written 
  upon 
  the 
  Hessian 
  Fly, 
  since 
  Mr. 
  George 
  Palmer, 
  

   of 
  Eevell's 
  Hall 
  Farm, 
  Hertford, 
  first 
  discovered 
  it 
  in 
  

   England, 
  on 
  July 
  27th, 
  1886, 
  none 
  of 
  them 
  have 
  given 
  

   any 
  account 
  of 
  its 
  life-history 
  from 
  their 
  oivn 
  observa- 
  

   tions, 
  but 
  have 
  preferred 
  to 
  copy 
  the 
  writings 
  of 
  others, 
  

   and, 
  in 
  so 
  doing, 
  have 
  copied 
  their 
  mistakes. 
  

  

  Before 
  entering 
  upon 
  a 
  detailed 
  account 
  of 
  the 
  notes 
  

   and 
  observations 
  which 
  I 
  have 
  made 
  during 
  the 
  past 
  

   four 
  years, 
  I 
  will 
  throw 
  upon 
  the 
  screen 
  a 
  photograph 
  

   of 
  a 
  barley 
  plant, 
  taken 
  from 
  a 
  field 
  at 
  Eevell's 
  Hall 
  

   Farm, 
  in 
  which 
  you 
  will 
  observe 
  that 
  the 
  stem 
  is 
  bent 
  

   down 
  sharply 
  at 
  the 
  second 
  joint; 
  this 
  has 
  been 
  caused 
  

   by 
  the 
  larvse 
  of 
  the 
  Hessian 
  Fly 
  {Cecidomyia 
  destructor, 
  

   Say), 
  and 
  it 
  was 
  this 
  appearance 
  of 
  bent 
  and 
  broken 
  

   stems 
  which 
  first 
  attracted 
  the 
  attention 
  of 
  Mr, 
  Palmer, 
  

   who 
  at 
  first 
  thought 
  the 
  barley 
  was 
  merely 
  "root-fallen 
  " 
  ; 
  

   but 
  a 
  more 
  careful 
  examination 
  of 
  the 
  bent 
  stems 
  revealed 
  

   the 
  peculiar 
  chestnut-coloured 
  "flax-seeds" 
  which 
  Prof. 
  

   Westwood 
  and 
  others 
  identified 
  as 
  the 
  puparia 
  of 
  the 
  

   Hessian 
  Fly. 
  

  

  TRANS. 
  ENT. 
  SOC. 
  LOND. 
  1891. 
  — 
  PART 
  II. 
  (jUNE.) 
  

  

  