﻿APPENDIX 
  III. 
  

  

  THE 
  HESSIAN 
  FLY 
  IE 
  SILESIA 
  m 
  1869. 
  

  

  [Extract 
  from 
  TJntersuchungen 
  ueber 
  Insectenschaden 
  auf 
  den 
  scUesischen 
  Getreidefeldem 
  im. 
  

   Sommer 
  1869, 
  von 
  Prof. 
  Dr. 
  Terd. 
  Cohn.*] 
  

  

  The 
  Hessian 
  Fly. 
  — 
  Cecidomyia 
  destructor. 
  

  

  An 
  examination 
  of 
  the 
  diseased 
  stalks 
  fully 
  verified 
  the 
  presumption 
  

   of 
  Mr. 
  Moritz-Eichhorn 
  that 
  it 
  was 
  not 
  frost 
  but 
  insects 
  that 
  attacked 
  

   them. 
  All 
  stalks 
  with 
  almost 
  no 
  exceptions 
  were 
  infested 
  with 
  dipter- 
  

   ous 
  insects; 
  and 
  though 
  several 
  species 
  were 
  engaged 
  in 
  the 
  work 
  of 
  

   destruction, 
  yet 
  the 
  Hessian 
  fly 
  devastated 
  the 
  most. 
  Its 
  traces 
  could 
  

   be 
  seen 
  on 
  numerous 
  dead 
  stalks, 
  which 
  remained 
  span 
  high 
  (12 
  to 
  15 
  

   centimeters), 
  turned 
  yellow-brown, 
  and 
  dried 
  up. 
  Other 
  stalks 
  de- 
  

   veloped 
  the 
  two 
  lowest 
  knots, 
  and 
  grew 
  two 
  or 
  three 
  spans 
  high 
  ; 
  the 
  

   upper 
  part 
  of 
  the 
  stalk 
  was 
  withered 
  and 
  shriveled, 
  and 
  surrounded 
  

   by 
  the 
  likewise 
  dried-up 
  and 
  blackish-yellow 
  leaf- 
  sheaths. 
  Externally 
  

   on 
  the 
  lower 
  stalk-joints 
  spots 
  could 
  be 
  seen 
  of 
  the 
  shape 
  of 
  a 
  button- 
  

   hole, 
  2^°^ 
  to 
  3™™ 
  broad 
  and 
  15"^°^ 
  to 
  20™^ 
  long, 
  of 
  straw-color, 
  bounded 
  

   by 
  a 
  black 
  margin, 
  which 
  latter 
  more 
  or 
  less 
  distributed 
  over 
  the 
  one- 
  

   half 
  of 
  the 
  stalk-joint, 
  the 
  black 
  coloration 
  sometimes 
  penetrating 
  to 
  

   the 
  pith 
  •, 
  at 
  times 
  two 
  such 
  button-hole-like 
  spots 
  occurred 
  above 
  each 
  

   other. 
  Eo 
  trace 
  of 
  an 
  animal 
  could 
  be 
  found 
  on 
  many 
  of 
  the 
  affected 
  

   stalks 
  ; 
  in 
  others 
  the 
  spot 
  was 
  hollowed 
  out, 
  and 
  there 
  were, 
  closely 
  

   oppressed 
  to 
  the 
  stalk, 
  covered 
  by 
  the 
  likewise 
  black 
  leaf-sheath, 
  from 
  

   one 
  to 
  four 
  smooth, 
  shiny, 
  blackish-brown 
  pupae, 
  by 
  their 
  flaxseed-like 
  

   shape 
  easily 
  recognized 
  as 
  those 
  of 
  the 
  Hessian 
  Fly 
  {Cecidomyia 
  de- 
  

   structor). 
  Again, 
  in 
  other 
  stalks, 
  the 
  pupae 
  were 
  higher, 
  at 
  the 
  base 
  of 
  

   the 
  decayed 
  stalk-point, 
  above 
  the 
  non-attacked, 
  2 
  to 
  3 
  inches 
  long, 
  low- 
  

   est 
  stalk 
  -joints, 
  covered 
  by 
  leaf-sheaths. 
  The 
  flies 
  raised 
  by 
  me 
  came 
  

   out 
  from 
  the 
  middle 
  of 
  June 
  till 
  July 
  22. 
  It 
  happened 
  that 
  I 
  still 
  found 
  

   in 
  wheat 
  from 
  Hundsfeld, 
  July 
  19, 
  besides 
  the 
  brown 
  flaxseed-like 
  pupae, 
  

   also 
  white 
  live 
  maggots, 
  together 
  with 
  such 
  just 
  transforming 
  into 
  pseudo- 
  

   pupae, 
  the 
  skin 
  having 
  turned 
  yellowish 
  already. 
  The 
  latter, 
  as 
  is 
  known, 
  

   forms 
  a 
  parchment-like 
  skin 
  within 
  which 
  the 
  maggot 
  becomes 
  a 
  pupa 
  

   and 
  then 
  a 
  perfect 
  fly, 
  with 
  blackish 
  wings, 
  dark 
  back, 
  and 
  blood-red 
  

   abdomen 
  j 
  the 
  fly, 
  therefore, 
  leaves 
  the 
  empty 
  brown 
  shell 
  together 
  with 
  

   the 
  colorless 
  pupa 
  shell, 
  pulled 
  out 
  of 
  the 
  latter. 
  Already, 
  June 
  15, 
  1 
  

   observed 
  near 
  Lissa, 
  in 
  company 
  with 
  Mr. 
  Haendler, 
  a 
  field 
  of 
  wheat, 
  

   a 
  broad 
  streak 
  of 
  which 
  near 
  its 
  boundary, 
  toward 
  winter 
  rye, 
  was 
  sim- 
  

   ilarly 
  attacked 
  as 
  just 
  described 
  at 
  Hundsfeld; 
  here, 
  too, 
  the 
  Hessian 
  

   fly 
  was 
  the 
  devastator. 
  The 
  same 
  was 
  the 
  case 
  on 
  wheat 
  fields 
  at 
  Ro- 
  

   gelwitz, 
  near 
  Mangschutz 
  (district 
  Brieg), 
  where 
  the 
  loss 
  was 
  estimated 
  

   as 
  five- 
  sixths 
  of 
  the 
  whole 
  amount. 
  From 
  a 
  sketch 
  made 
  by 
  Lieutenant 
  

  

  • 
  Translated 
  by 
  Dr. 
  C. 
  F. 
  Gissler. 
  

  

  [39] 
  

  

  