﻿350 
  Mr. 
  F. 
  Enock's 
  life-history 
  of 
  

  

  stand 
  any 
  amount 
  of 
  wet 
  ; 
  the 
  pots 
  in 
  which 
  I 
  have 
  kept 
  

   isolated 
  puparia 
  and 
  those 
  with 
  the 
  infested 
  straws 
  have 
  

   frequently 
  been 
  flooded 
  for 
  hours 
  together 
  an 
  inch 
  deep, 
  

   without 
  sustaining 
  the 
  slightest 
  injury 
  ; 
  in 
  fact, 
  moisture 
  

   is 
  of 
  most 
  vital 
  importance 
  to 
  their 
  existence. 
  

  

  On 
  Aug. 
  9th, 
  1889, 
  in 
  a 
  letter 
  to 
  the 
  'Echo,' 
  I 
  ex- 
  

   pressed 
  an 
  opinion 
  that, 
  owing 
  to 
  the 
  wet 
  weather 
  and 
  

   backwardness 
  of 
  the 
  wheat 
  and 
  barley 
  crops, 
  there 
  was 
  

   every 
  probability 
  of 
  being 
  three 
  broods 
  instead 
  of 
  tico, 
  

   the 
  second 
  brood 
  emerging 
  early 
  in 
  August 
  ; 
  these 
  laid 
  

   their 
  eggs 
  on 
  young 
  plants, 
  and 
  some 
  of 
  the 
  flies 
  of 
  the 
  

   third 
  brood 
  did 
  emerge 
  in 
  September. 
  

  

  Though 
  moisture 
  is 
  of 
  such 
  importance 
  to 
  their 
  welfare, 
  

   and 
  hastens 
  their 
  development, 
  it 
  is 
  astonishing 
  how 
  very 
  

   tenacious 
  they 
  are 
  of 
  life. 
  In 
  season 
  of 
  drought 
  their 
  

   development 
  may 
  be 
  greatly 
  retarded 
  — 
  far 
  longer 
  than 
  

   even 
  Herr 
  Wagner 
  appears 
  to 
  have 
  observed, 
  for 
  he 
  

   states 
  that 
  " 
  The 
  first 
  part 
  of 
  the 
  Hessian 
  Troops 
  left 
  

   Cassel 
  in 
  March, 
  1776, 
  landing 
  in 
  Long 
  Island 
  Aug. 
  12th; 
  

   the 
  packing 
  straw 
  used 
  by 
  them 
  must 
  have 
  been 
  that 
  

   grown 
  in 
  1775, 
  and 
  in 
  the 
  ordinary 
  course 
  of 
  Nature 
  the 
  

   pupa 
  which 
  might 
  have 
  been 
  in 
  the 
  straw 
  ought 
  to 
  have 
  

   hatched 
  April 
  and 
  May, 
  1776, 
  and 
  the 
  flies 
  of 
  course 
  died 
  

   before 
  reaching 
  Long 
  Island." 
  This 
  would 
  have 
  been 
  

   correct, 
  supposing 
  all 
  the 
  flies 
  had 
  emerged 
  ; 
  and 
  though 
  

   it 
  is 
  a 
  matter 
  of 
  very 
  small 
  importance 
  whether 
  the 
  fly 
  

   was 
  introduced 
  into 
  America 
  by 
  the 
  Hessian 
  troops, 
  or 
  

   from 
  some 
  other 
  source, 
  the 
  following 
  facts 
  will 
  show 
  

   that 
  under 
  certain 
  conditions 
  the 
  development 
  of 
  this 
  

   insect 
  is 
  frequently 
  retarded 
  to 
  a 
  very 
  long 
  time, 
  or 
  more 
  

   than 
  twice 
  as 
  long 
  as 
  Herr 
  Wagner 
  states. 
  

  

  On 
  March 
  9th, 
  1889, 
  I 
  received 
  from 
  Mr. 
  Palmer 
  two 
  

   sacks 
  of 
  barley 
  screenings, 
  one 
  from 
  the 
  harvest 
  of 
  1888, 
  

   and 
  the 
  other 
  from 
  1887 
  ; 
  this 
  one, 
  Mr. 
  Palmer 
  informed 
  

   me, 
  had 
  been 
  tied 
  up 
  all 
  ready 
  to 
  send 
  to 
  me, 
  but 
  from 
  

   some 
  cause 
  had 
  been 
  put 
  away 
  in 
  a 
  dry 
  room 
  and 
  

   forgotten 
  until 
  sending 
  the 
  1888 
  screenings, 
  from 
  which, 
  

   on 
  April 
  25th, 
  I 
  picked 
  a 
  large 
  number 
  of 
  puparia. 
  

   I 
  then 
  examined 
  some 
  from 
  the 
  1887 
  crop, 
  and 
  was 
  

   astonished 
  to 
  find 
  several 
  alive 
  ! 
  though 
  verj^ 
  much 
  

   shrivelled 
  ; 
  and 
  out 
  of 
  a 
  hundred 
  puparia 
  which 
  I 
  

   dissected, 
  sixty-seven 
  had 
  dried 
  up 
  ; 
  from 
  eighteen 
  the 
  

   parasites 
  had 
  emerged, 
  and 
  in 
  fifteen 
  the 
  larvne 
  of 
  the 
  

   Hessian 
  Fly 
  were 
  still 
  alive, 
  shrivelled 
  up 
  to 
  half 
  their 
  

   natural 
  length. 
  I 
  placed 
  these 
  on 
  damp 
  sand, 
  and 
  two 
  

  

  