﻿190 
  Transactions. 
  — 
  Zoology, 
  

  

  We 
  are 
  all 
  familiar 
  with 
  the 
  appearance 
  of 
  the 
  outer 
  shell 
  or 
  shield 
  of 
  

   the 
  apple 
  scale. 
  The 
  shield 
  varies 
  considerably 
  in 
  different 
  genera 
  ; 
  some- 
  

   times 
  it 
  is 
  round, 
  sometimes 
  long, 
  sometimes 
  white, 
  sometimes 
  brown, 
  but 
  

   it 
  invariably 
  exhibits, 
  in 
  some 
  part 
  or 
  other 
  of 
  its 
  extent, 
  when 
  taken 
  from 
  

   the 
  adult 
  female 
  insect, 
  the 
  two 
  pellicles 
  which 
  she 
  has 
  discharged 
  in 
  her 
  

   earlier 
  transformations. 
  In 
  my 
  plate 
  V., 
  fig. 
  la, 
  is 
  shown 
  part 
  of 
  the 
  

   shield 
  of 
  the 
  apple 
  scale, 
  mounted 
  to 
  show 
  the 
  pellicles. 
  In 
  the 
  shield 
  of 
  

   the 
  male 
  insect, 
  in 
  certain 
  species, 
  only 
  one 
  pellicle 
  appears, 
  the 
  insect 
  

   undergoing 
  only 
  one 
  transformation 
  before 
  the 
  pupa 
  stage. 
  

  

  The 
  female 
  insect, 
  having 
  arrived 
  at 
  her 
  full 
  growth, 
  fills 
  her 
  shield 
  with 
  

   eggs. 
  A 
  figure 
  of 
  its 
  appearance 
  is 
  given 
  in 
  plate 
  V., 
  fig. 
  lb, 
  for 
  the 
  apple 
  

   scale. 
  '•' 
  

  

  The 
  young 
  insect 
  shows 
  no 
  sexual 
  differences. 
  It 
  is 
  oval 
  in 
  shape 
  

   (plate 
  v., 
  fig. 
  le), 
  with 
  six 
  legs, 
  two 
  antennae, 
  and 
  two 
  eyes. 
  

  

  The 
  female, 
  discarding 
  her 
  first 
  skin, 
  throws 
  off 
  also 
  at 
  the 
  same 
  time 
  

   all 
  external 
  organs 
  except 
  the 
  mouth 
  or 
  rostrum. 
  In 
  the 
  first 
  pellicle 
  

   attached 
  to 
  her 
  shield 
  the 
  remains 
  of 
  the 
  antenna 
  may 
  almost 
  always 
  be 
  

   seen. 
  The 
  legs 
  are 
  not 
  to 
  be 
  found, 
  and 
  I 
  cannot 
  say 
  what 
  becomes 
  of 
  

   them. 
  The 
  insect, 
  thus 
  debarrassed 
  of 
  her 
  limbs 
  and 
  eyes, 
  becomes 
  only 
  

   an 
  inert 
  mass. 
  She 
  remains 
  thus 
  for 
  some 
  time, 
  merely 
  feeding 
  and 
  grow- 
  

   ing, 
  still 
  retaining 
  an 
  oval 
  shape, 
  as 
  shown 
  by 
  the 
  second 
  pellicles 
  in 
  the 
  

   shield. 
  Throwing 
  off 
  this 
  pellicle, 
  she 
  appears 
  in 
  her 
  adult 
  stage, 
  a 
  des- 
  

   cription 
  of 
  which 
  must 
  be 
  left 
  tiU 
  I 
  come 
  to 
  each 
  species, 
  as 
  they 
  differ 
  

   considerably. 
  

  

  "What 
  I 
  have 
  just 
  said 
  as 
  to 
  the 
  discarding 
  of 
  the 
  limbs 
  is, 
  like 
  every 
  

   rule, 
  subject 
  to 
  some 
  exception. 
  In 
  one 
  or 
  two 
  sxDecies, 
  chiefly 
  of 
  the 
  genus 
  

   Mijtilaspis, 
  a 
  pair 
  of 
  minute 
  protuberances, 
  which 
  M. 
  Signoret 
  states 
  are 
  

   rudimentary 
  antenn©, 
  are 
  visible 
  on 
  the 
  head. 
  

  

  The 
  adult 
  female, 
  whatever 
  her 
  ahape, 
  oval 
  or 
  round, 
  is 
  much 
  cor- 
  

   rugated, 
  in 
  fact 
  made 
  up 
  of 
  rolls 
  of 
  fat, 
  with 
  the 
  exception 
  of 
  the 
  head 
  — 
  

   which 
  is 
  usually 
  smooth, 
  and 
  of 
  the 
  abdomen 
  — 
  which 
  is 
  peculiarly 
  shaped 
  

   and 
  marked. 
  The 
  colour 
  of 
  the 
  insect 
  as 
  a 
  whole 
  varies 
  — 
  being 
  sometimes 
  

   whitish, 
  sometimes 
  pale 
  yellow, 
  sometimes 
  red. 
  

  

  In 
  all 
  cases 
  that 
  I 
  have 
  observed 
  the 
  abdominal 
  region 
  is 
  of 
  a 
  bright 
  yellow 
  

   colour, 
  and 
  it 
  is 
  from 
  the 
  markings 
  of 
  this 
  portion 
  of 
  the 
  body 
  that 
  the 
  

   specific 
  differences 
  of 
  the 
  genera 
  of 
  Diaspidae 
  are 
  taken. 
  My 
  plate 
  V,, 
  fig. 
  

   Id, 
  gives 
  the 
  appearance 
  of 
  the 
  abdomen 
  of 
  Mytilaspis 
  p>omonim, 
  the 
  

   apple 
  scale, 
  which 
  I 
  have 
  taken 
  as 
  the 
  type 
  of 
  the 
  group. 
  It 
  will 
  be 
  seen 
  

   that 
  the 
  corrugations 
  of 
  the 
  body 
  end 
  a 
  short 
  distance 
  from 
  the 
  posterior 
  

   extremity, 
  which 
  has 
  a 
  curved 
  oiitline, 
  broken 
  by 
  numerous 
  small 
  lobes, 
  

   intermixed 
  with 
  scaly 
  hahs, 
  The 
  anal 
  opening 
  is 
  at 
  what 
  might 
  be 
  ternaed 
  

  

  