﻿SCALE 
  INSECTS 
  OF 
  IMPORTANCE 
  333: 
  

  

  White 
  scale 
  insect 
  of 
  the 
  ivy 
  

  

  Aspidiotus 
  hederae 
  Vallot 
  

  

  PLATE 
  7 
  

  

  This 
  species 
  is 
  rather 
  common 
  in 
  greenhouses 
  in 
  the 
  state, 
  and 
  not 
  in- 
  

   frequently 
  it 
  causes 
  considerable 
  damage, 
  specially 
  to 
  ivy, 
  its 
  favorite 
  

   food 
  plant. 
  The 
  ivy 
  is 
  not 
  always 
  killed, 
  but 
  the 
  white 
  scales 
  on 
  the 
  

   dark 
  green 
  leaves 
  render 
  it 
  unsalable. 
  Large 
  quantities 
  of 
  this 
  foliage 
  

   plant 
  have 
  been 
  rendered 
  worthless 
  in 
  this 
  manner. 
  

  

  Description. 
  Infested 
  plants 
  may 
  be 
  recognized 
  by 
  the 
  white, 
  irreg- 
  

   ular 
  patches 
  of 
  scale 
  insects. 
  An 
  examination 
  of 
  one 
  of 
  these 
  under 
  a 
  

   lens 
  will 
  show 
  it 
  to 
  be 
  composed 
  of 
  a 
  number 
  of 
  yellowish- 
  white, 
  circular 
  

   scales, 
  each 
  with 
  a 
  deeper 
  yellow 
  cast 
  skin, 
  or 
  exuviae, 
  a 
  little 
  to 
  one 
  side 
  

   of 
  the 
  center. 
  The 
  appearance 
  of 
  an 
  infested 
  spray 
  of 
  ivy 
  is 
  well 
  shown 
  

   in 
  figure 
  7. 
  The 
  large, 
  yellowish-white 
  scales 
  are 
  usually 
  surrounded 
  by 
  

   a 
  number 
  of 
  small 
  white 
  ones. 
  Such 
  a 
  group 
  is 
  represented 
  much 
  en- 
  

   larged 
  in 
  figure 
  6, 
  and 
  a 
  full-grown 
  female 
  scale, 
  which 
  is 
  about 
  -^ 
  inch' 
  

   in 
  diameter, 
  more 
  enlarged 
  in 
  figure 
  4, 
  while 
  a 
  young 
  white 
  scale 
  is 
  shown 
  

   very 
  greatly 
  enlarged 
  in 
  figure 
  3. 
  Some 
  of 
  the 
  yellowish, 
  active 
  young 
  

   can 
  usually 
  be 
  found 
  on 
  an 
  infested 
  leaf. 
  One 
  is 
  shown 
  much 
  enlarged 
  

   in 
  figure 
  2. 
  The 
  removal 
  of 
  an 
  adult 
  scale 
  may 
  uncover 
  a 
  yellowish 
  

   female, 
  represented 
  in 
  figure 
  i, 
  or 
  there 
  may 
  be 
  found 
  only 
  her 
  shriveled 
  

   remains, 
  shown 
  greatly 
  magnified 
  in 
  figure 
  5, 
  and 
  possibly 
  a 
  few 
  very 
  

   minute 
  yellowish 
  eggs 
  and 
  one 
  or 
  two 
  active 
  young 
  (fig. 
  8). 
  

  

  Life 
  history. 
  The 
  conditions 
  in 
  the 
  greenhouse 
  usually 
  permit 
  this 
  

   insect 
  to 
  breed 
  continuously, 
  so 
  that 
  there 
  is 
  no 
  demarcation 
  of 
  broods. 
  

   Adult 
  females, 
  half-grown 
  individuals 
  and 
  crawling 
  young 
  can 
  usually 
  

   be 
  found 
  at 
  almost 
  any 
  time. 
  This 
  insect 
  lives 
  outdoors 
  in 
  the 
  southern 
  

   states, 
  and, 
  under 
  these 
  conditions, 
  Prof. 
  Comstock 
  is 
  of 
  the 
  opinion 
  that 
  

   there 
  are 
  at 
  least 
  two 
  generations 
  annually. 
  He 
  bred 
  adult 
  males 
  in 
  

   April 
  from 
  specimens 
  received 
  both 
  from 
  California 
  and 
  Florida, 
  but 
  I 
  

   have 
  been 
  unable 
  to 
  find 
  a 
  sign 
  of 
  this 
  sex 
  on 
  a 
  badly 
  infested 
  ivy 
  plant 
  

   kept 
  under 
  observation 
  for 
  some 
  months. 
  This 
  species 
  is 
  apparently 
  both 
  

   oviparous 
  and 
  ovoviviparous. 
  I 
  have 
  observed 
  eggs 
  and 
  living 
  young 
  

   besides 
  empty 
  egg 
  shells 
  under 
  female 
  scales, 
  and 
  Mr 
  Coquillett 
  states 
  

   that 
  he 
  has 
  witnessed 
  the 
  birth 
  of 
  living 
  young. 
  

  

  Distribution. 
  This 
  is 
  a 
  well-known 
  European 
  species 
  which 
  has 
  a 
  

   wide 
  distribution, 
  having 
  been 
  recorded 
  from 
  such 
  distant 
  places 
  as 
  

   Australia, 
  Chile 
  and 
  Cuba. 
  It 
  has 
  attained 
  a 
  general 
  distribution 
  in 
  the 
  

  

  