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  Ijy 
  a 
  silvery 
  U-shaped 
  spot 
  on 
  the 
  middle 
  of 
  the 
  fore 
  wing 
  and 
  an 
  oval 
  

   silvery 
  dot 
  adjoining 
  it 
  on 
  the 
  outside. 
  

  

  The 
  number 
  of 
  generations 
  annually 
  has 
  not 
  been 
  satisfactorily 
  de- 
  

   termined. 
  Riley 
  believed 
  that 
  there 
  were 
  probably 
  four 
  in 
  the 
  latitude 
  of 
  

   Washington, 
  D. 
  C. 
  This 
  caterpillar 
  has 
  an 
  enormously 
  destructive 
  

   parasitic 
  enemy, 
  a 
  minute 
  hymenopterous 
  insect, 
  which 
  pupates 
  within 
  

   the 
  skin 
  of 
  its 
  dead 
  host 
  and 
  emerges 
  in 
  almost 
  incredible 
  numbers, 
  over 
  

   twenty-five 
  hundred 
  having 
  been 
  counted 
  which 
  must 
  have 
  come 
  from 
  a 
  

   single 
  infested 
  larva. 
  In 
  a 
  large 
  lot 
  of 
  larvae 
  collected 
  by 
  us 
  at 
  Urbana, 
  

   only 
  one 
  example 
  escaped 
  parasitism, 
  and 
  Dr. 
  Riley 
  reports 
  a 
  similar 
  

   observation 
  upon 
  fifty 
  larvK 
  collected 
  by 
  him. 
  

  

  The 
  Celery 
  Pi.usia. 
  

  

  Plusia 
  simplex 
  Guen. 
  

  

  This 
  is 
  our 
  commonest 
  Illinois 
  Plusia. 
  It 
  occurs 
  generally 
  in 
  the 
  

   United 
  States 
  east 
  of 
  the 
  Rocky 
  Mountains, 
  as 
  well 
  as 
  in 
  New 
  Mexico 
  

   and 
  the 
  Hudson 
  Bay 
  Territory. 
  It 
  is 
  a 
  very 
  destructive 
  celery 
  insect, 
  and 
  

   we 
  have 
  bred 
  it 
  from 
  a 
  larva 
  found 
  feeding 
  on 
  the 
  sugar 
  beet. 
  It 
  differs 
  

   from 
  the 
  cabbage 
  species 
  in 
  the 
  fact 
  that 
  its 
  spiracles 
  are 
  distinctly 
  

   Tinged 
  with 
  black, 
  according 
  to 
  Coquillett, 
  while 
  in 
  the 
  cabbage 
  Plusia 
  

   these 
  rings 
  are 
  indistinct, 
  partial, 
  or 
  wanting. 
  There 
  are 
  believed 
  to 
  be 
  

   three 
  broods 
  of 
  this 
  species 
  in 
  a 
  year. 
  The 
  caterpillars 
  of 
  the 
  first 
  

   generation 
  of 
  the 
  year 
  hatch 
  late 
  in 
  May 
  and 
  get 
  their 
  growth 
  late 
  in 
  June 
  

   or 
  early 
  in 
  July. 
  The 
  life 
  of 
  the 
  second 
  generation 
  extends 
  from 
  the 
  

   first 
  part 
  of 
  July 
  to 
  the 
  middle 
  of 
  September, 
  and 
  the 
  third 
  begins 
  to 
  

   issue 
  from 
  the 
  egg 
  early 
  in 
  October. 
  This 
  brood 
  hibernates 
  about 
  half- 
  

   grown, 
  attaining 
  full 
  size 
  during 
  the 
  latter 
  half 
  of 
  April, 
  This 
  account, 
  

   coftipiled 
  from 
  Coquillett's 
  statement 
  in 
  the 
  Eleventh 
  Illinois 
  Report, 
  is 
  

   confirmed 
  by 
  our 
  collections, 
  in 
  which 
  the 
  moths 
  of 
  this 
  species 
  occur 
  

   twice 
  in 
  April, 
  ten 
  times 
  early 
  in 
  May, 
  ten 
  times 
  between 
  July 
  15 
  th 
  and 
  

   August. 
  15th, 
  and 
  six 
  times 
  in 
  the 
  latter 
  half 
  of 
  September. 
  

  

  The 
  Zebra-caterpillar. 
  

  

  Mamesira 
  picta 
  Harr. 
  

  

  Although 
  evidently 
  preferring 
  cabbage 
  and 
  other 
  cruciferous 
  plants, 
  

   this 
  abundant 
  and 
  conspicuous 
  caterpillar 
  occasionally 
  attacks 
  beets. 
  

   It 
  seems 
  to 
  be 
  somewhat 
  whimsical 
  in 
  its 
  food 
  habits. 
  It 
  has 
  been 
  re- 
  

   ported 
  by 
  Felt, 
  of 
  New 
  York, 
  as 
  excessively 
  abundant 
  in 
  timothy 
  and 
  

   as 
  the 
  probable 
  agent 
  in 
  the 
  destruction 
  of 
  twenty 
  acres 
  of 
  oats. 
  Other 
  

   food 
  plants 
  recorded 
  are 
  cauliflower, 
  turnip, 
  rutabaga, 
  bean, 
  pea, 
  carrot, 
  

   celery, 
  potato, 
  spinach, 
  asparagus, 
  buckwheat, 
  corn, 
  clover, 
  currant, 
  

   cranberry, 
  apple, 
  orange, 
  willow, 
  spruce, 
  mignonette, 
  aster, 
  sweet 
  pea, 
  

   snowberry, 
  honeysuckle, 
  smartweed, 
  burdock, 
  and 
  lamb's-quarters. 
  It 
  

  

  