﻿238 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  extraordinary 
  warmth 
  of 
  that 
  period; 
  the 
  cold 
  May 
  had 
  retarded 
  the 
  growth 
  of 
  the 
  

   crop, 
  so 
  that 
  the 
  larvsB 
  of 
  the 
  second 
  generation 
  growing 
  in 
  the 
  young 
  stalks 
  did 
  

   totally 
  destroy 
  the 
  germs 
  of 
  the 
  ears 
  ; 
  had 
  the 
  spring 
  been 
  warmer, 
  the 
  shoots 
  would 
  

   have 
  grown 
  out 
  the 
  damages 
  of 
  the 
  fly 
  ; 
  now 
  most 
  part 
  of 
  the 
  sprouts 
  had 
  been 
  killed. 
  

   That 
  at 
  least 
  is 
  the 
  explanation 
  I 
  may 
  give 
  to 
  the 
  facts. 
  

  

  I 
  collected 
  some 
  pupse 
  in 
  the 
  wheat 
  field 
  on 
  3d 
  of 
  August, 
  which 
  I 
  put 
  in 
  a 
  small 
  

   glass," 
  but 
  none 
  crept 
  out, 
  some 
  being 
  killed 
  by 
  fungi 
  and 
  some 
  by 
  Pteromalinse.^^s 
  

   Nevertheless, 
  I 
  send 
  you 
  the 
  glass. 
  I 
  fear 
  the 
  communication 
  I 
  send 
  you 
  to-day 
  will 
  

   not 
  suffice 
  for 
  the 
  determination 
  of 
  the 
  species 
  ; 
  next 
  summer 
  I 
  shall 
  attend 
  to 
  the 
  

   matter, 
  and 
  I 
  hope 
  to 
  be 
  able 
  to 
  send 
  you 
  fresh 
  specimens, 
  which 
  may 
  suffice 
  to 
  decide 
  

   the 
  question. 
  

  

  Meanwhile 
  I 
  remain, 
  yours 
  very 
  respectfully, 
  

  

  FERDINAND 
  COHN. 
  

  

  It 
  will 
  also 
  be 
  seen 
  by 
  the 
  translation 
  of 
  Koppen's 
  article 
  (see 
  ap- 
  

   pendix) 
  that 
  in 
  1879 
  and 
  1880 
  Cecidomyia 
  destructor 
  w^s 
  '^distributed 
  

   over 
  a 
  great 
  part 
  of 
  middle 
  and 
  Southern 
  Eussia," 
  and 
  it 
  seems 
  proba- 
  

   ble 
  from 
  his 
  statement 
  that 
  as 
  early 
  as 
  1852 
  it 
  was 
  abundant 
  in 
  the 
  dis- 
  

   trict 
  of 
  Oharkow. 
  

  

  From 
  all 
  the 
  information 
  we 
  have 
  before 
  us, 
  and 
  in 
  the 
  light 
  of 
  Wag- 
  

   ner^s 
  investigations, 
  we 
  are 
  strongly 
  disposed 
  to 
  believe: 
  

  

  1. 
  That 
  the 
  Hessian 
  Fly 
  had 
  appeared 
  in 
  the 
  eastern 
  United 
  States 
  

   before 
  the 
  Eevolutionary 
  war, 
  and 
  that 
  it 
  could 
  not 
  have 
  been 
  intro- 
  

   duced 
  by 
  the 
  Hessians. 
  

  

  2. 
  That 
  the 
  Hessian 
  Fly 
  has 
  never 
  been 
  known 
  to 
  inhabit 
  England 
  

   or 
  northern 
  Europe. 
  

  

  3. 
  That 
  it 
  was 
  not 
  known 
  in 
  Germany 
  before 
  1857. 
  

  

  4. 
  That 
  it 
  has 
  " 
  from 
  time 
  immemorial 
  '^ 
  been 
  an 
  inhabitant 
  of 
  wheat 
  

   fields 
  on 
  the 
  shores 
  of 
  the 
  Mediterranean, 
  in 
  Spain, 
  at 
  Toulon 
  in 
  France, 
  

   at 
  l^aples, 
  in 
  Minorca, 
  and 
  Asia 
  Minor. 
  

  

  5. 
  That 
  it 
  probably 
  originated 
  in 
  this 
  region 
  or 
  farther 
  east, 
  the 
  prob- 
  

   able 
  original 
  habitat 
  of 
  the 
  wheat 
  and 
  other 
  cereals. 
  

  

  6. 
  That 
  it 
  was 
  introduced 
  from 
  southern 
  Europe, 
  either 
  southern 
  

   France 
  or 
  other 
  Mediterranean 
  regions, 
  perhaps 
  Asia 
  Minor, 
  before 
  

   the 
  Eevolutionary 
  war. 
  

  

  That 
  the 
  Cecidomyia 
  destructor 
  originated 
  in 
  southern 
  Europe 
  and 
  

   western 
  Asia, 
  i, 
  e., 
  about 
  the 
  shores 
  of 
  the 
  Mediterranean 
  Sea, 
  seems 
  

   most 
  probable 
  from 
  the 
  statements 
  of 
  Herrick 
  and 
  Dana 
  which 
  we 
  have 
  

   quoted. 
  From 
  this 
  region 
  it 
  has 
  possibly 
  spread 
  into 
  Germany 
  j 
  and 
  

   from 
  Asia 
  Minor 
  and 
  perhaps 
  southern 
  Eussia 
  it 
  has 
  probably 
  spread 
  

   into 
  central 
  Eussia. 
  

  

  We 
  are, 
  then, 
  disposed 
  to 
  adhere 
  to 
  Wagner^s 
  conclusions 
  that 
  the 
  

   insect 
  could 
  not 
  possibly 
  have 
  been 
  indigenous 
  in 
  Germany; 
  and 
  we 
  

   are 
  therefore 
  unable 
  to 
  agree 
  with 
  Dr. 
  Hagen 
  that 
  the 
  Hessian 
  Fly 
  is 
  

   ^'an 
  indigenous 
  American 
  insect," 
  and 
  that 
  it 
  '' 
  was 
  Indigenous 
  here 
  as 
  

   well 
  as 
  in 
  the 
  Old 
  World." 
  

  

  iieprofessor 
  Riley 
  has 
  sul)mitted 
  specimens 
  to 
  Mr. 
  L. 
  O. 
  Howard, 
  who 
  writes 
  us 
  as 
  follows: 
  "The 
  

   European 
  Hessian 
  fly 
  parasite 
  received 
  from 
  Professor 
  Cohn 
  is 
  a 
  Platygaster, 
  but 
  as 
  this 
  genus 
  has 
  not 
  

   Leen 
  worked 
  up 
  systematically 
  in 
  Europe, 
  and 
  as 
  there 
  are 
  scores 
  of 
  isolated 
  descriptions, 
  it 
  is 
  practi- 
  

   cally 
  impossible 
  to 
  determine 
  it 
  specifically." 
  

  

  