﻿WAGNER 
  ON 
  THE 
  HESSIAN 
  FLY. 
  [33] 
  

  

  farmer" 
  has 
  certainly 
  not 
  passed 
  the 
  bent 
  wheat 
  stalks 
  without 
  taking 
  

   a 
  good 
  look 
  at 
  the 
  enemy 
  and 
  comparing 
  it 
  with 
  the 
  one 
  long 
  before 
  

   observed 
  ! 
  

  

  Fitch 
  puts 
  much 
  stress 
  on 
  certain 
  statements 
  of 
  observed 
  devasta- 
  

   tions 
  of 
  wheat 
  and 
  other 
  cereals 
  made 
  a 
  long 
  time 
  ago 
  in 
  Middle 
  Europe. 
  

   Scarcely 
  one 
  of 
  these 
  citations 
  has 
  with 
  certainty 
  special 
  reference 
  to 
  the 
  

   wheat- 
  worm. 
  Baron 
  Meininger^s 
  report 
  on 
  destructions 
  by 
  insects 
  oc- 
  

   curring 
  in 
  the 
  fields 
  near 
  Weikendorf, 
  in 
  Saxe-Goburg, 
  do 
  not 
  point 
  to 
  

   the 
  wheat- 
  worm, 
  becausQ. 
  the 
  reporter 
  calls 
  the 
  maggot 
  " 
  light-green," 
  

   wjiich 
  recalls 
  the 
  character 
  of 
  GJilorops. 
  All 
  reports 
  from 
  Middle 
  and 
  

   ]!^orth 
  Germany 
  published 
  in 
  later 
  years 
  on 
  the 
  wheat- 
  worm 
  agree 
  in 
  

   this, 
  that 
  the 
  appearance 
  of 
  the 
  insect 
  is 
  an 
  entirely 
  new 
  one. 
  In 
  many 
  

   districts 
  of 
  Korth 
  Germany 
  excellent 
  entomologists 
  have 
  not 
  even 
  thus 
  

   far 
  been 
  able 
  to 
  discover 
  a 
  trace 
  o:^ 
  the 
  insect. 
  A 
  gradual 
  progress 
  of 
  the 
  

   insect 
  showed 
  itself 
  toward 
  the 
  nortli 
  within 
  the 
  few 
  later 
  years, 
  suffi- 
  

   ciently 
  pointing 
  to 
  their 
  southern 
  origin. 
  Therefore 
  we 
  can 
  infer 
  : 
  the 
  

   distribution 
  of 
  the 
  wheat- 
  worm 
  can 
  be 
  traced 
  back 
  to 
  the 
  Orient 
  ', 
  thenec 
  

   the 
  insect 
  just 
  settled 
  on 
  the 
  islands 
  and 
  along 
  the 
  South 
  European 
  

   coast, 
  and 
  then 
  was 
  partly 
  introduced 
  to 
  E'orth 
  America, 
  partly 
  and 
  

   successively 
  progressed 
  in 
  a 
  northward 
  direction. 
  

  

  § 
  9. 
  — 
  Parasites. 
  

  

  The 
  wheat- 
  worm 
  harbors 
  a 
  considerable 
  number 
  of 
  hymenopterous 
  

   parasites, 
  selected 
  by 
  nature 
  to 
  check 
  its 
  extreme 
  multiplication. 
  An 
  

   accurate 
  knowledge 
  of 
  the 
  natural 
  history 
  of 
  these 
  parasites, 
  belonging 
  

   to 
  the 
  two 
  groups 
  Ghaleididce 
  and 
  Proctotrupidce, 
  is 
  certainly 
  necessary 
  

   if 
  we 
  wish, 
  in 
  choosing 
  antidotes, 
  to 
  be 
  free 
  of 
  errors.* 
  

  

  Fitch 
  states 
  in 
  his 
  paper, 
  published 
  fifteen 
  years 
  ago, 
  his 
  intention 
  to 
  

   study 
  " 
  the 
  history 
  of 
  these 
  and 
  other 
  parasites 
  of 
  the 
  Geeidomyidce^ 
  and 
  

   to 
  prepare 
  a 
  special 
  memoir." 
  Whether 
  such 
  a 
  memoir 
  afterwards 
  ap- 
  

   peared 
  I 
  do 
  not 
  know. 
  From 
  a 
  sketch 
  copied 
  by 
  him 
  from 
  Herrick^s 
  paper 
  

   there 
  are 
  at 
  least 
  four 
  species 
  of 
  parasites 
  destroying 
  the 
  wheat- 
  worm. 
  

   One 
  of 
  them, 
  a 
  species 
  of 
  Flatygaster, 
  pierces 
  the 
  eggs 
  of 
  the 
  flyj 
  of 
  the 
  

   three 
  other 
  species 
  which 
  presumably 
  pierce 
  the 
  maggot 
  only 
  Ceraphron 
  

   destructor 
  Say 
  is 
  mentioned, 
  and 
  it 
  is 
  asserted 
  that 
  the 
  piercing 
  is 
  done 
  

   through 
  the 
  leaf-sheath, 
  which 
  I, 
  however, 
  in 
  view 
  of 
  the 
  short 
  ovipositor, 
  

   doubt. 
  Herrick 
  does 
  not 
  seem 
  to 
  have 
  used 
  special 
  names 
  for 
  the 
  dif- 
  

   ferent 
  species 
  ; 
  but 
  Ceraphron 
  destructor 
  Say 
  became 
  also 
  doubtful, 
  since, 
  

   as 
  proved 
  by 
  Dr. 
  Foerster 
  in 
  his 
  Hymenopterological 
  Studies 
  (page 
  98), 
  

   a 
  great 
  misconception 
  as 
  to 
  the 
  genus 
  Ceraphron 
  Jurine 
  was 
  caused 
  by 
  

   Latreille 
  and 
  later 
  by 
  Nees. 
  

  

  At 
  the 
  time 
  I 
  sent 
  to 
  Dr. 
  Foerster, 
  in 
  Aachen, 
  a 
  sufacient 
  number 
  of 
  

   the 
  raised 
  parasites, 
  with 
  the 
  request 
  to 
  study 
  them 
  scientifically. 
  

  

  The 
  little 
  that 
  I 
  learned 
  about 
  these 
  parasites 
  I 
  will 
  here 
  communi- 
  

   cate. 
  Scarcely 
  a 
  day 
  passedfrom 
  beginning 
  of 
  August 
  till 
  end 
  of 
  Septem- 
  

   ber 
  without 
  receiving 
  some 
  parasites 
  hatched. 
  According 
  to 
  a 
  super- 
  

  

  ♦ThelawunmistakaWy 
  applied 
  all 
  through 
  the 
  animal 
  kingdom 
  as 
  to 
  the 
  regulation 
  of 
  the 
  numher 
  

   of 
  obnoxious 
  animals 
  by 
  such 
  as 
  persecute 
  them, 
  and 
  thereby 
  reproduce 
  the 
  eventually 
  disturbed 
  

   equilibrium, 
  nowhere 
  strikes 
  our 
  admiration 
  more 
  than 
  in 
  insects. 
  There 
  is 
  a 
  considerable 
  number 
  

   among 
  those 
  which 
  in 
  various 
  ways, 
  by 
  continued 
  practice 
  of 
  their 
  work 
  of 
  destruction, 
  become 
  true 
  

   benefactors 
  to 
  mankind. 
  But 
  this 
  is 
  not 
  enough. 
  Before 
  in 
  a 
  certain 
  case 
  of 
  devastation 
  the 
  number 
  

   of 
  parasites 
  gains 
  the 
  upper 
  hand 
  over 
  the 
  devastators, 
  as 
  a 
  rule 
  a 
  number 
  of 
  years 
  pass, 
  often 
  for 
  us 
  

   accompanied 
  by 
  great 
  losses. 
  Shall 
  we 
  then 
  fold 
  our 
  hands 
  in 
  our 
  laps, 
  surrender 
  the 
  work 
  of 
  destruc- 
  

   tion 
  solely 
  to 
  our 
  brave 
  friends, 
  carelessly 
  awaiting 
  the 
  catastrophe 
  ? 
  Never 
  ; 
  this 
  would 
  be 
  vn-ong 
  

   and 
  unjustifiable. 
  Man, 
  as 
  the 
  dominator 
  of 
  the 
  earth, 
  was 
  given 
  the 
  faculty 
  of 
  scrutinizing 
  nature 
  

   and 
  of 
  finding 
  remedies 
  against 
  various 
  hindrances 
  opposed 
  to 
  his 
  endeavors 
  to 
  render 
  the 
  earth 
  in- 
  

   habitable. 
  The 
  more 
  we 
  progress 
  in 
  the 
  knowledge 
  of 
  insects, 
  the 
  more 
  we 
  study 
  their 
  biology 
  and 
  

   other 
  peculiarities, 
  the 
  less 
  shall 
  we 
  err 
  in 
  choosing 
  remedies 
  to 
  destroy 
  the 
  enemy. 
  

   3 
  AP 
  E 
  

  

  