﻿HAGEN 
  ON 
  THE 
  SOURCE 
  OF 
  THE 
  HESSIAN 
  FLY. 
  [49] 
  

  

  numerous, 
  laying 
  every 
  wheat- 
  field 
  under 
  contribution 
  for 
  their 
  support." 
  

   Is 
  it 
  not 
  obvious 
  that 
  the 
  same 
  course 
  may 
  have 
  happened 
  with 
  the 
  Hes- 
  

   sian 
  fly? 
  The 
  more 
  so 
  since 
  just 
  at 
  the 
  time 
  of 
  its 
  appearance 
  in 
  Long 
  

   Island 
  and 
  the 
  adjoining 
  country 
  the 
  culture 
  of 
  wheat 
  was 
  prominently 
  

   advanced. 
  Since 
  we 
  know 
  that 
  at 
  the 
  utmost 
  during 
  six 
  weeks 
  in 
  the 
  

   year 
  only 
  is 
  the 
  importation 
  of 
  the 
  fly 
  possible, 
  such 
  an 
  importation 
  to 
  

   America 
  before 
  the 
  discovery 
  of 
  steamships 
  is 
  almost 
  inconceivable. 
  

   Even 
  if 
  j)urposely 
  undertaken 
  with 
  all 
  care, 
  such 
  an 
  importation 
  would 
  

   almost 
  surely 
  have 
  been 
  a 
  failure. 
  

  

  Dr. 
  Wagner 
  has 
  felt 
  the 
  strength 
  of 
  those 
  arguments, 
  and 
  supposes 
  

   that 
  importation 
  had 
  been 
  possible 
  only 
  from 
  the 
  nearest 
  coast 
  of 
  France. 
  

   He 
  believes 
  that 
  the 
  lesser 
  distance, 
  as 
  well 
  as 
  the 
  frequent 
  trade 
  with 
  

   France, 
  makes 
  it 
  more 
  probable. 
  But 
  why 
  not 
  accept 
  that 
  the 
  fly 
  was 
  

   indigenous 
  here 
  as 
  well 
  as 
  in 
  the 
  Old 
  World 
  ? 
  There 
  are 
  Diptera 
  identi- 
  

   cal 
  with 
  European 
  species 
  which 
  nobedy 
  would 
  think 
  to 
  have 
  been 
  im- 
  

   ported. 
  I 
  may 
  mention 
  the 
  common 
  Trichocera 
  regeXationis^ 
  which 
  be- 
  

   longs 
  to 
  a 
  related 
  group. 
  The 
  species 
  is 
  common 
  here, 
  and 
  was 
  ob- 
  

   served 
  by 
  me 
  13 
  years 
  ago. 
  But 
  last 
  winter 
  I 
  had 
  specimens 
  sent 
  

   me 
  from 
  Maine, 
  stating 
  that 
  this 
  insect 
  had 
  never 
  been 
  seen 
  there 
  be- 
  

   fore, 
  and 
  had 
  been 
  extremely 
  troublesome. 
  I 
  know 
  well 
  that 
  many 
  

   animals 
  — 
  higher 
  and 
  lower 
  ones 
  — 
  have 
  been 
  imported, 
  because 
  the 
  facts 
  

   are 
  well 
  recorded 
  ; 
  I 
  believe 
  that 
  a 
  number 
  of 
  others 
  have 
  also 
  been 
  im-' 
  

   ported 
  for 
  which 
  the 
  facts 
  are 
  not 
  recorded. 
  But 
  I 
  see 
  no 
  reason 
  to 
  go 
  

   farther, 
  and 
  am 
  prepared 
  to 
  accept 
  that 
  the 
  same 
  species 
  in 
  both 
  coun- 
  

   tries 
  may 
  have 
  been 
  developed 
  under 
  similar 
  conditions. 
  I 
  consider, 
  

   therefore, 
  the 
  Hessian 
  fly 
  to 
  be 
  an 
  indig'enous 
  American 
  insect, 
  and 
  not 
  

   imported 
  by 
  Hessian 
  troops. 
  

  

  A 
  few 
  words 
  more 
  concerning 
  the 
  periods 
  of 
  unusual 
  abundance 
  of 
  

   the 
  fl}^ 
  I 
  was 
  very 
  much 
  interested 
  in 
  the 
  study 
  of 
  the 
  table 
  given 
  by 
  

   Dr. 
  Packard, 
  but 
  I 
  arrived 
  at 
  the 
  conclusion 
  that 
  the 
  table 
  is 
  not 
  suffi- 
  

   cient, 
  and 
  indeed 
  is 
  considered 
  \>j 
  Dr. 
  Packard 
  himself 
  as 
  very 
  imper- 
  

   fect. 
  Concerning 
  New 
  England 
  Dr. 
  A. 
  Fitch's 
  statement 
  has 
  been 
  over- 
  

   looked, 
  Regs., 
  viii., 
  p. 
  203, 
  that 
  the 
  fly 
  was 
  very 
  iujurious 
  in 
  Berks 
  Co., 
  

   Mass., 
  in 
  1779. 
  

  

  The 
  year 
  1823 
  for 
  Maine 
  and 
  1857 
  for 
  Ohio, 
  are 
  not 
  marked 
  at 
  all 
  in 
  

   the 
  table, 
  and 
  both 
  the 
  records 
  state 
  that 
  the 
  farmers 
  had 
  ventilated 
  

   earnestly 
  the 
  question 
  to 
  give 
  up 
  entirely 
  the 
  cultivation 
  of 
  wheat. 
  The 
  

   only 
  conclusion 
  to 
  be 
  made 
  by 
  the 
  table 
  would 
  be 
  that 
  with 
  an 
  intermis- 
  

   sion 
  of 
  thirty 
  to 
  fort}' 
  years 
  a 
  period 
  of 
  superabundance 
  follows. 
  Per- 
  

   haps 
  a 
  careful 
  study 
  of 
  the 
  old 
  records 
  from 
  1748 
  to 
  1750 
  would 
  give 
  

   some 
  evidence 
  if 
  the 
  fly 
  has 
  ever 
  been 
  obnoxious 
  here 
  before 
  the 
  war. 
  

   It 
  is 
  a 
  curious 
  fact 
  that 
  such 
  an 
  intermission 
  of 
  the 
  a?ppearance 
  of 
  the 
  

   Hessian 
  fly 
  has 
  occurred 
  just 
  in 
  that 
  quarter 
  of 
  the 
  century 
  during 
  

   w^hich 
  the 
  most 
  ardent 
  collector 
  and 
  student 
  of 
  the 
  N. 
  American 
  Dip- 
  

   tera 
  — 
  I 
  may 
  say 
  the 
  founder 
  of 
  the 
  American 
  Dipterology 
  — 
  was 
  here. 
  

   In 
  fact. 
  Baron 
  von 
  Osten 
  Sacken 
  has 
  never 
  met 
  here 
  with 
  this 
  Hessian 
  

   fly, 
  which 
  is 
  not 
  represented 
  in 
  his 
  collection 
  nor 
  in 
  Prof. 
  Loew's, 
  both 
  

   now 
  in 
  the 
  Museum 
  in 
  Cambridge. 
  

  

  Note. 
  — 
  As 
  the 
  paper 
  was 
  going 
  through 
  the 
  press 
  I 
  received 
  two 
  

   pairs 
  of 
  G. 
  destructor 
  from 
  Prof. 
  J. 
  A. 
  Cook, 
  the 
  first 
  American 
  speci- 
  

   mens 
  which 
  have 
  come 
  to 
  my 
  hands. 
  In 
  comparing 
  these 
  with 
  tAvo 
  

   pairs 
  of 
  C. 
  secalina 
  from 
  Prussia 
  and 
  Hesse, 
  I 
  was 
  astonished 
  to 
  find 
  

   the 
  American 
  insects 
  twice 
  as 
  large 
  as 
  the 
  European 
  ones, 
  and 
  almost 
  

   entirely 
  black. 
  I 
  think 
  they 
  look 
  so 
  different 
  that 
  the 
  identity 
  is 
  per- 
  

   haps 
  not 
  sure. 
  But 
  a 
  larger 
  series 
  from 
  both 
  countries 
  and 
  a 
  more 
  

   detailed 
  knowledge 
  of 
  Diptera 
  than 
  are 
  at 
  my 
  commaud 
  would 
  be 
  

   needed 
  to 
  decide 
  the 
  question. 
  

   4 
  AP 
  E 
  

  

  