﻿SCALE 
  INSECTS 
  OF 
  IMPORTANCE 
  347 
  

  

  definite 
  and 
  well 
  marked 
  and 
  of 
  considerable 
  size, 
  the 
  specimen 
  is 
  a 
  third 
  

   stage, 
  female 
  A. 
  perniciosus, 
  though 
  not 
  yet 
  gravid. 
  The 
  second 
  

   stage 
  of 
  these 
  four 
  species 
  shows 
  only 
  the 
  vague, 
  somewhat 
  parenthesis- 
  

   shaped 
  thickenings 
  mentioned 
  above 
  and 
  seen 
  in 
  the 
  second 
  stage 
  illustra- 
  

   tions. 
  Of 
  course 
  the 
  third 
  stage 
  of 
  the 
  other 
  three 
  species 
  is 
  marked 
  by 
  the 
  

   ventral 
  glands 
  even 
  before 
  the 
  young 
  appear 
  within 
  the 
  body. 
  In 
  addi- 
  

   tion, 
  the 
  occasional 
  difficulty 
  in 
  detecting 
  the 
  arrangement 
  of 
  the 
  plates 
  

   must 
  always 
  be 
  remembered. 
  

  

  Key 
  

  

  A 
  Incisions 
  wide 
  and 
  not 
  very 
  deep. 
  Second 
  pair 
  of 
  lobes 
  small 
  

   when 
  present. 
  Median 
  lobes 
  rather 
  broad. 
  

   B 
  With 
  fringing 
  plates. 
  Second 
  pair 
  of 
  lobes 
  rudimentary 
  or 
  want- 
  

   ing 
  A. 
  ancylus 
  

  

  BB 
  Plates 
  inconspicuous 
  or 
  wanting. 
  Second 
  pair 
  of 
  lobes 
  usually 
  

  

  distinct, 
  though 
  small 
  A. 
  ostreaeformis 
  

  

  AA 
  Incisions 
  narrow. 
  Lobes 
  distinctly 
  two 
  pairs, 
  of 
  good 
  size. 
  

   Median 
  lobes 
  rather 
  narrow. 
  

   B 
  Lobes 
  nearly 
  parallel. 
  Fringing 
  plates. 
  Thickenings 
  on 
  either 
  

   side 
  of 
  the 
  first 
  incision 
  subequal. 
  No 
  ventral 
  glands 
  even 
  in 
  

  

  gravid 
  female 
  A, 
  perniciosus 
  

  

  BB 
  Lobes 
  usually 
  strongly 
  approximating 
  at 
  tips. 
  Plates 
  incon- 
  

   spicuous 
  or 
  wanting. 
  Thickenings 
  on 
  either 
  side 
  of 
  first 
  incisions 
  

   distinctly 
  unequal. 
  Ventral 
  glands 
  present 
  in 
  adult 
  .A. 
  f 
  o 
  r 
  b 
  e 
  s 
  i 
  

  

  Aspidiotus 
  forbesi 
  Johns 
  

  

  PLATES 
  12 
  AND 
  13, 
  FIGURES 
  I 
  

  

  This 
  species 
  appears 
  to 
  approach 
  A. 
  perniciosus 
  most 
  closely 
  in 
  

   general 
  outline. 
  (Compare 
  each 
  figure 
  with 
  the 
  second 
  figure 
  of 
  the 
  same 
  

   plate, 
  A. 
  perniciosus.) 
  It 
  has 
  four 
  distinct 
  lobes: 
  the 
  median 
  ones 
  

   are 
  notched 
  on 
  the 
  outer 
  margins 
  and 
  approximate 
  at 
  the 
  tips, 
  the 
  second 
  

   ones 
  are 
  about 
  half 
  the 
  size 
  of 
  the 
  first 
  and 
  usually 
  notched 
  on 
  the 
  outer 
  

   margin. 
  They 
  also 
  slant 
  slightly 
  inward, 
  giving 
  the 
  species 
  in 
  general 
  a 
  

   decidedly 
  pigeon-toed 
  appearance. 
  The 
  lobes 
  are 
  close 
  together, 
  because 
  

   the 
  incisions 
  (two 
  pairs) 
  are 
  narrow. 
  The 
  first 
  incisions 
  are 
  quite 
  deep. 
  

   The 
  second 
  are 
  not 
  so 
  much 
  so. 
  Prof. 
  Johnson 
  in 
  the 
  original 
  description 
  

   and 
  figure 
  located 
  four 
  spines 
  on 
  each 
  side 
  of 
  the 
  median 
  line; 
  these 
  are 
  

   quite 
  prominent. 
  There 
  is 
  a 
  fifth 
  pair 
  often 
  visible 
  near 
  the 
  union 
  of 
  the 
  

   terminal 
  and 
  the 
  penultimate 
  segments. 
  In 
  general 
  the 
  spines 
  do 
  not 
  

  

  