﻿the 
  Hessian 
  Fly. 
  341 
  

  

  and 
  12th 
  segments, 
  but 
  some 
  had 
  emerged 
  at 
  the 
  other 
  

   end 
  ; 
  these 
  I 
  carefully 
  examined, 
  and 
  found 
  that 
  the 
  fly 
  

   had 
  emerged 
  on 
  the 
  ventral 
  side, 
  or 
  that 
  nearest 
  to 
  the 
  

   stem, 
  showing 
  that 
  in 
  these 
  instances 
  the 
  larva 
  had 
  not 
  

   turned 
  round, 
  and 
  it 
  would 
  in 
  all 
  probability 
  have 
  

   perished 
  had 
  not 
  the 
  puparium 
  become 
  detached 
  from 
  

   the 
  surrounding 
  sheath. 
  A 
  few 
  had 
  emerged 
  at 
  the 
  

   dorsal 
  side, 
  appearing 
  to 
  have 
  revolved 
  half-way 
  round, 
  

   so 
  bringing 
  the 
  head 
  to 
  the 
  front 
  and 
  outwards, 
  though 
  

   doivnivards 
  ; 
  but 
  in 
  every 
  one 
  of 
  the 
  hundreds 
  bred 
  from 
  

   coarctate 
  larvee 
  in 
  their 
  normal 
  position 
  in 
  the 
  straw, 
  the 
  

   fly 
  had 
  emerged 
  at 
  the 
  top 
  end. 
  

  

  On 
  July 
  5th, 
  1888, 
  the 
  larvae 
  were 
  most 
  plentiful 
  in 
  the 
  

   barley, 
  and 
  as 
  the 
  crop 
  was 
  very 
  backward 
  and 
  stunted 
  

   in 
  May, 
  when 
  the 
  females 
  were 
  ovipositing, 
  the 
  larvse 
  in 
  

   nearly 
  every 
  one 
  of 
  the 
  400 
  straws 
  cut 
  were 
  not 
  more 
  

   than 
  an 
  inch 
  above 
  ground, 
  and 
  in 
  many 
  instances 
  the 
  

   barley 
  was 
  bent 
  at 
  the 
  ground-line. 
  

  

  I 
  noticed 
  that 
  the 
  small 
  thin 
  plants 
  were 
  more 
  fre- 
  

   quently 
  attacked 
  than 
  the 
  stronger 
  ones, 
  and 
  generally 
  

   contained 
  several 
  larvse 
  ; 
  the 
  tail-end 
  protruding 
  from 
  

   between 
  the 
  folds 
  of 
  the 
  leaf-sheath. 
  The 
  position 
  of 
  the 
  

   larva 
  was 
  quite 
  different 
  to 
  that 
  in 
  the 
  1887 
  crop, 
  when 
  

   the 
  barley 
  was 
  much 
  stronger 
  and 
  the 
  bend 
  nearly 
  always 
  

   at 
  the 
  second 
  joint, 
  and 
  often 
  at 
  the 
  third, 
  7 
  to 
  10 
  in. 
  

   above 
  ground. 
  

  

  The 
  larva 
  is 
  most 
  delicate, 
  and 
  dries 
  up 
  if 
  the 
  straw 
  is 
  

   cut 
  before 
  the 
  maggot 
  has 
  reached 
  its 
  full 
  growth 
  ; 
  so 
  

   that 
  the 
  only 
  plan 
  to 
  observe 
  the 
  changes 
  is 
  to 
  have 
  a 
  

   number 
  of 
  living 
  plants 
  of 
  various 
  sizes 
  ; 
  in 
  fact, 
  when 
  

   the 
  flies 
  are 
  emerging, 
  sow 
  about 
  a 
  dozen 
  grains 
  in 
  a 
  

   six-inch 
  pot, 
  always 
  keeping 
  up 
  a 
  constant 
  supply. 
  

  

  The 
  second 
  stage 
  of 
  the 
  larva, 
  known 
  as 
  the 
  puparium, 
  

   or, 
  more 
  correctly, 
  the 
  coarctate 
  larva, 
  and 
  more 
  popu- 
  

   larly 
  as 
  the 
  "flax-seed" 
  state, 
  has 
  been 
  so 
  frequently 
  and 
  

   fully 
  described 
  that 
  I 
  need 
  not 
  add 
  to 
  it 
  ; 
  but 
  one 
  thing 
  

   I 
  have 
  constantly 
  noticed 
  is 
  that 
  when 
  the 
  leaf-sheath 
  is 
  

   removed 
  carefully, 
  and 
  the 
  upper 
  or 
  tail-end 
  of 
  the 
  flax- 
  

   seed 
  drawn 
  away 
  from 
  the 
  stem, 
  the 
  mouth 
  always 
  

   appears 
  to 
  be 
  fastened 
  by 
  some 
  sort 
  of 
  white 
  cement 
  or 
  

   starch, 
  which 
  in 
  a 
  measure 
  prevents 
  the 
  puparium 
  from 
  

   being 
  too 
  readily 
  shaken 
  out 
  of 
  place 
  before 
  its 
  time 
  ; 
  

   though 
  no 
  doubt 
  vast 
  numbers 
  are 
  scattered 
  broadcast 
  

   when 
  the 
  harvest 
  is 
  cut 
  and 
  carried, 
  and, 
  wherever 
  the 
  

  

  2a2 
  

  

  