﻿SCALE 
  INSECTS 
  OF 
  IMPORTANCE 
  

  

  309 
  

  

  female, 
  in 
  from 
  ^^ 
  to 
  40 
  days. 
  The 
  detailed 
  studies 
  made 
  at 
  Washing- 
  

   ton 
  show 
  that 
  four 
  full 
  generations 
  are 
  developed 
  normally 
  in 
  that 
  lati- 
  

   tude 
  and 
  that 
  there 
  may 
  be 
  a 
  partial 
  filth. 
  The 
  production 
  of 
  a 
  few 
  

   young 
  each 
  day 
  for 
  some 
  six 
  weeks 
  leads 
  to 
  a 
  confusion 
  of 
  broods 
  toward 
  

   the 
  end 
  of 
  the 
  season, 
  and 
  their 
  exact 
  number 
  can 
  not 
  be 
  determined 
  

   without 
  special 
  study. 
  This 
  insect 
  breeds 
  in 
  the 
  vicinity 
  of 
  Albany 
  from 
  

   the 
  latter 
  part 
  of 
  June 
  through 
  October. 
  After 
  making 
  due 
  allowance 
  

   for 
  the 
  difference 
  in 
  latitude 
  and 
  the 
  slower 
  development 
  in 
  cooler 
  

   weather, 
  we 
  can 
  hardly 
  expect 
  more 
  than 
  three 
  full 
  generations 
  normally, 
  

   with 
  a 
  possibility 
  of 
  a 
  fourth 
  under 
  exceptionally 
  favorable 
  conditions. 
  

   This 
  is 
  confirmed 
  by 
  the 
  studies 
  of 
  Prof, 
  V. 
  H. 
  Lowe 
  at 
  Geneva. 
  He 
  

   found 
  the 
  average 
  duration 
  of 
  the 
  period 
  of 
  growth 
  to 
  be 
  49J 
  days, 
  which 
  

   gives 
  just 
  about 
  time 
  enough 
  for 
  three 
  full 
  generations 
  during 
  the 
  growing 
  

   season. 
  

  

  Food 
  plants. 
  This 
  insect 
  has 
  been 
  recorded 
  on 
  a 
  considerable 
  num- 
  

   ber 
  of 
  food 
  plants, 
  and 
  its 
  ability 
  to 
  live 
  on 
  so 
  many 
  varieties 
  adds 
  very 
  

   much 
  to 
  the 
  difficulty 
  of 
  exterminating 
  or 
  controlling 
  it. 
  The 
  following 
  

   is 
  a 
  list 
  of 
  food 
  plants, 
  as 
  compiled 
  by 
  Dr 
  Lintner, 
  with 
  a 
  few 
  additions 
  

   by 
  Dr 
  Howard 
  and 
  from 
  office 
  records. 
  

  

  Tiliaceae 
  

  

  Linden 
  

   Celastraceae 
  

  

  Euonymus 
  

   Rosaceae 
  

  

  Almond 
  

  

  Peach 
  

  

  Apricot 
  

  

  Plum 
  

  

  Cherry 
  

  

  Spiraea 
  

  

  Raspberry 
  

  

  Rose 
  

  

  Hawthorn 
  

  

  Cotoneaster 
  

  

  Pear 
  

  

  Apple 
  

  

  Quince 
  

  

  Flowering 
  quince 
  

   Saxifragaceae 
  

  

  Gooseberry 
  

  

  Saxifragaceae 
  {continued) 
  

  

  Currant 
  

  

  Flowering 
  currant 
  

   Ebenaceae 
  

  

  Persimmon 
  

   Leguminoseae 
  

  

  Acacia 
  

   O 
  1 
  e 
  ac 
  e 
  a 
  e 
  

  

  Lilac 
  

   Urticaceae 
  

  

  Elm 
  

  

  Osage 
  orange 
  

   J 
  uglandaceae 
  

  

  English 
  walnut 
  

  

  Pecan 
  

   Betulaceae 
  

  

  Alder 
  ? 
  

   Salicaceae 
  

  

  Weeping 
  willow 
  

  

  Laurel-leaved 
  willow 
  (from 
  

   Asia) 
  

  

  I 
  

  

  