﻿FOOD 
  PLANTS. 
  27 
  

  

  place 
  in 
  whatever 
  location 
  the 
  prepupa 
  may 
  be, 
  and 
  the 
  transparent 
  

   and 
  delicate 
  empty 
  skin 
  is 
  found 
  behind 
  the 
  pupa. 
  It 
  was 
  observed 
  

   during 
  the 
  fall 
  that 
  pupa? 
  exposed 
  to 
  a 
  low 
  temperature 
  did 
  not 
  com- 
  

   plete 
  their 
  development 
  to 
  the 
  adult 
  stage. 
  These, 
  when 
  later 
  placed 
  

   in 
  the 
  greenhouse, 
  changed 
  to 
  adults 
  unless 
  exposed 
  to 
  the 
  unfavorable 
  

   conditions 
  too 
  long, 
  when 
  all 
  were 
  killed. 
  

  

  During 
  the 
  pupal 
  stage 
  several 
  external 
  changes 
  take 
  place. 
  At 
  

   first 
  the 
  ocelli 
  are 
  not 
  evident, 
  but 
  as 
  the 
  pupa 
  develops 
  these 
  become 
  

   prominent 
  in 
  a 
  triangle 
  between 
  the 
  folded 
  antennae 
  Then 
  the 
  reticu- 
  

   lations 
  of 
  the 
  body 
  begin 
  to 
  appear, 
  and 
  within 
  two 
  days 
  of 
  the 
  

   emergence 
  of 
  the 
  adult 
  the 
  pupa 
  begins 
  to 
  darken 
  and 
  the 
  legs, 
  

   antenna?, 
  and 
  wings 
  begin 
  to 
  show 
  blackish 
  bands. 
  The 
  adult 
  

   emerges 
  in 
  a 
  manner 
  similar 
  to 
  the 
  molting 
  of 
  the 
  larva. 
  Emergence 
  

   has 
  been 
  noted 
  at 
  all 
  hours 
  of 
  the 
  day, 
  and 
  there 
  seems 
  to 
  be 
  no 
  par- 
  

   ticular 
  time 
  for 
  its 
  occurrence. 
  

  

  FOOD 
  PLANTS. 
  

  

  This 
  insect 
  seems 
  to 
  be 
  nearly 
  as 
  omnivorous 
  as 
  the 
  onion 
  thrips, 
  

   as 
  the 
  following 
  list 
  of 
  food 
  plants 
  upon 
  which 
  it 
  has 
  been 
  reared 
  or 
  

   observed 
  during 
  the 
  past 
  two 
  years 
  by 
  the 
  writer 
  would 
  indicate. 
  

   These 
  have 
  been 
  divided 
  into 
  economic 
  and 
  wild 
  food 
  plants, 
  and 
  

   under 
  each 
  will 
  be 
  given 
  notes 
  on 
  injury 
  and 
  appearance 
  of 
  injured 
  

   plants. 
  

  

  BEANS. 
  

  

  The 
  injurious 
  occurrence 
  of 
  this 
  insect 
  on 
  the 
  foliage 
  of 
  beans 
  gives 
  

   to 
  it 
  its 
  common 
  name. 
  It 
  has 
  been 
  observed 
  by 
  the 
  writer 
  to 
  feed 
  on 
  

   bean 
  foliage 
  in 
  the 
  adult 
  and 
  larval 
  stages 
  from 
  early 
  in 
  February, 
  

   in 
  sheltered 
  places, 
  until 
  the 
  plants 
  are 
  killed 
  by 
  frost 
  in 
  the 
  fall. 
  

   In 
  the 
  spring 
  the 
  wild 
  plants 
  are 
  first 
  up, 
  and 
  the 
  attack 
  is 
  largely 
  

   concentrated 
  on 
  them, 
  so 
  that 
  when 
  the 
  beans 
  come 
  up 
  they 
  are 
  not 
  

   immediately 
  attacked. 
  However, 
  in 
  a 
  few 
  weeks 
  the 
  insect 
  spreads 
  

   to 
  the 
  beans, 
  thereafter 
  increasing 
  in 
  numbers 
  until 
  in 
  the 
  late 
  sum- 
  

   mer 
  and 
  fall 
  much 
  injury 
  is 
  done. 
  When 
  snap 
  beans 
  are 
  infested 
  

   the 
  adults 
  first 
  attack 
  the 
  leaves, 
  and 
  while 
  feeding 
  lay 
  countless 
  eggs 
  

   in 
  the' 
  tissue. 
  The 
  larva? 
  on 
  hatching 
  begin 
  to 
  feed, 
  and 
  gradually 
  

   the 
  green 
  coloring 
  matter 
  is 
  entirely 
  removed 
  from 
  the 
  underside 
  of 
  

   the 
  leaf. 
  This 
  becomes 
  white 
  and 
  covered 
  with 
  the 
  black 
  spots 
  of 
  

   excrement. 
  The 
  infestation 
  then 
  spreads 
  to 
  the 
  surface 
  and 
  to 
  other 
  

   parts 
  of 
  the 
  plant. 
  As 
  the 
  feeding 
  rroes 
  on 
  the 
  leaves 
  lose 
  all 
  color, 
  

   become 
  white, 
  or 
  dry 
  up 
  and 
  turn 
  brown 
  and 
  drop 
  off. 
  As 
  the 
  infes- 
  

   tation 
  increases, 
  the 
  stems 
  and 
  pods 
  themselves 
  are 
  also 
  attacked 
  and 
  

   mined. 
  A 
  badly 
  infested 
  field 
  appears 
  as 
  if 
  scorched 
  by 
  (ire. 
  The 
  

   lima 
  bean 
  and 
  pink 
  bean 
  suffer 
  in 
  the 
  same 
  way. 
  The 
  blackeve 
  cow- 
  

   I 
  eas 
  this 
  past 
  season 
  were 
  almost 
  immune 
  from 
  the 
  attack 
  of 
  this 
  

   insect, 
  even 
  in 
  fields 
  in 
  which 
  the 
  pink 
  beans 
  and 
  -piny 
  Lettuce 
  were 
  

   very 
  badly 
  infested. 
  

  

  