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  year. 
  The 
  manner 
  in 
  which 
  the 
  adults 
  escape 
  from 
  the 
  puparium 
  

   is 
  described. 
  They 
  Hve 
  ordinarily 
  about 
  two 
  weeks, 
  but 
  if 
  fed 
  on 
  

   sugar 
  in 
  confinement 
  hfe 
  may 
  be 
  prolonged 
  to 
  three 
  weeks. 
  There 
  

   are 
  three 
  broods 
  in 
  the 
  year, 
  but 
  there 
  is 
  a 
  good 
  deal 
  of 
  overlapping 
  

   of 
  the 
  various 
  stages, 
  owing 
  to 
  differences 
  in 
  the 
  times 
  of 
  emergence, 
  

   so 
  that 
  eggs, 
  larvae, 
  pupae 
  and 
  adults 
  are 
  all 
  found 
  to 
  occur 
  simulta- 
  

   neously 
  from 
  June 
  to 
  September. 
  

  

  The 
  buccal-pharyngeal 
  apparatus 
  is 
  described 
  and 
  its 
  anatomy 
  

   compared 
  with 
  that 
  of 
  Pegomyia 
  bicolor, 
  Wied., 
  and 
  P. 
  nigritarsis, 
  Zett. 
  

   With 
  regard 
  to 
  remedies, 
  manuring 
  in 
  autumn 
  rather 
  than 
  in 
  spring 
  

   is 
  recommended. 
  Spraying 
  with 
  paraffin 
  emulsion, 
  8 
  parts 
  of 
  water, 
  

   1 
  part 
  of 
  soap 
  and 
  i^ 
  parts 
  of 
  paraffin, 
  has 
  been 
  found 
  efficient. 
  Deep 
  

   ploughing 
  in 
  order 
  to 
  bury 
  the 
  puparia 
  and 
  thus 
  render 
  the 
  emergence 
  

   of 
  the 
  adults 
  difficult 
  is 
  only 
  considered 
  useful 
  in 
  light 
  soils. 
  The 
  

   following 
  emulsion 
  is 
  said 
  to 
  be 
  effective 
  in 
  preventing 
  oviposition, 
  if 
  

   applied 
  early 
  in 
  the 
  season 
  : 
  — 
  Two 
  pints 
  of 
  paraffin 
  are 
  added 
  to 
  4 
  

   parts 
  of 
  soft 
  soap 
  and 
  the 
  mixture 
  brought 
  to 
  the 
  boil 
  ; 
  a 
  small 
  

   quantity 
  of 
  boihng 
  water 
  is 
  then 
  stirred 
  in 
  and 
  the 
  whole 
  well 
  mixed 
  

   until 
  a 
  good 
  emulsion 
  is 
  obtained 
  ; 
  to 
  this 
  4 
  ounces 
  of 
  95 
  per 
  cent, 
  of 
  

   nicotin 
  are 
  added 
  and 
  the 
  whole 
  made 
  up 
  to 
  100 
  gallons 
  by 
  the 
  addi- 
  

   tion 
  of 
  more 
  water. 
  If 
  kept 
  well 
  corked 
  in 
  a 
  drum, 
  the 
  mixture 
  can 
  

   be 
  stored 
  and 
  used 
  at 
  any 
  time, 
  and 
  is 
  suitable 
  as 
  a 
  fine 
  spray. 
  The 
  

   cost 
  of 
  this 
  mixture 
  works 
  out 
  at 
  about 
  35. 
  9d. 
  per 
  100 
  gallons. 
  Three 
  

   species 
  of 
  parasitic 
  Hymenoptera 
  were 
  reared 
  from 
  the 
  puparia 
  of 
  

   P. 
  hyoscyami. 
  Of 
  these, 
  two 
  were 
  Braconids 
  belonging 
  to 
  the 
  genus 
  

   OpiuSj 
  one 
  of 
  them 
  being 
  0. 
  nitidulator, 
  Nees. 
  The 
  third, 
  which 
  was 
  

   comparatively 
  rare, 
  was 
  a 
  Proctotrupid, 
  probably 
  a 
  hyper-parasite 
  of 
  

   one 
  or 
  both 
  of 
  the 
  two 
  species 
  of 
  Opius. 
  The 
  percentage 
  of 
  parasitism 
  

   was 
  rather 
  high, 
  and, 
  as 
  the 
  season 
  advanced, 
  increased 
  in 
  intensity 
  

   from 
  about 
  14 
  per 
  cent, 
  in 
  July 
  to 
  a 
  much 
  as 
  43 
  per 
  cent, 
  in 
  September. 
  

   The 
  hibernating 
  pupae 
  do 
  not 
  appear 
  to 
  be 
  heavily 
  attacked. 
  Damp 
  

   weather 
  is 
  said 
  to 
  have 
  the 
  effect 
  of 
  reducing 
  the 
  number 
  of 
  parasites, 
  

   but 
  the 
  author's 
  observations 
  in 
  1912 
  and 
  1913 
  showed 
  that 
  the 
  

   difference 
  was 
  not 
  very 
  marked. 
  Experiments 
  as 
  to 
  the 
  migration 
  of 
  

   these 
  insects 
  from 
  one 
  host 
  plant 
  to 
  another 
  did 
  not 
  produce 
  evidence 
  

   that 
  this 
  transition 
  takes 
  place 
  with 
  the 
  abruptness 
  which 
  many 
  authors 
  

   assume. 
  FertiHsed 
  females, 
  reared 
  from 
  larvae 
  which 
  had 
  been 
  

   fed 
  on 
  belladonna 
  leaves, 
  were 
  placed 
  in 
  breeding 
  cages 
  containing 
  

   fresh 
  mangold 
  plants, 
  but 
  in 
  no 
  instance 
  were 
  eggs 
  deposited. 
  The 
  

   converse 
  experiment, 
  from 
  mangold 
  to 
  belladonna, 
  had 
  the 
  same 
  

   negative 
  result. 
  The 
  author 
  thinks 
  it 
  possible 
  that 
  within 
  the 
  limits 
  

   of 
  a 
  single 
  polyphagous 
  species 
  certain 
  well 
  defined 
  " 
  biologic 
  " 
  species 
  

   may 
  be 
  established, 
  each 
  of 
  which 
  shows 
  a 
  marked 
  tendency 
  

   towards 
  a 
  particular 
  food-plant. 
  Differences 
  between 
  the 
  imagos 
  of 
  

   P, 
  hyoscyami 
  fed 
  on 
  henbane 
  and 
  belladonna 
  are 
  clearly 
  observable. 
  

   At 
  Dartford, 
  Kent, 
  where 
  henbane 
  and 
  belladonna 
  are 
  gro\^Ti 
  com- 
  

   mercially 
  and 
  close 
  together, 
  it 
  has 
  been 
  found 
  that 
  in 
  some 
  years 
  as 
  

   much 
  as 
  80 
  per 
  cent, 
  of 
  the 
  former 
  crop 
  is 
  damaged, 
  while 
  the 
  latter 
  

   remains 
  unaffected, 
  but 
  when 
  henbane 
  is 
  absent, 
  belladonna 
  is 
  quite 
  

   attractive 
  to 
  the 
  fly. 
  It 
  has 
  been 
  suggested 
  to 
  the 
  author 
  by 
  Dr. 
  Imms 
  

   that 
  P. 
  betae 
  is 
  a 
  species 
  confined 
  to 
  the 
  Chenopodiaceae 
  and 
  

   P. 
  hyoscyami 
  a 
  second 
  species 
  confined 
  to 
  the 
  Solanaceae, 
  and 
  he 
  thinks 
  

   it 
  possible 
  that 
  these 
  are 
  physiological 
  species 
  which 
  have 
  undergone 
  

  

  