﻿The 
  Scent- 
  scale 
  of 
  Pinacopteryx 
  liliana. 
  385 
  

  

  from 
  each 
  other, 
  giving 
  rise 
  to 
  a 
  cavity 
  in 
  which 
  the 
  central 
  

   substance 
  is 
  seen 
  in 
  section 
  as 
  an 
  oval 
  or 
  fusiform 
  body 
  in 
  

   contact 
  with 
  the 
  upper 
  layer, 
  a 
  clear 
  space 
  being 
  left 
  

   between 
  the 
  central 
  substance 
  and 
  the 
  lower 
  layer 
  of 
  the 
  

   scale. 
  The 
  body 
  itself 
  tapers 
  off 
  distally 
  and 
  proximally, 
  

   and 
  frequently 
  shows 
  clefts 
  in 
  its 
  substance 
  which 
  have 
  

   no 
  visible 
  relation 
  with 
  any 
  structural 
  feature. 
  In 
  the 
  

   neighbourhood 
  of 
  each 
  of 
  its 
  thinned 
  or 
  pointed 
  extremities 
  

   there 
  is 
  an 
  appearance 
  as 
  of 
  a 
  small 
  accumulation 
  of 
  

   granules 
  which 
  seem 
  not 
  to 
  share 
  in 
  the 
  blue 
  staining. 
  

   These 
  no 
  doubt 
  are 
  the 
  " 
  granules 
  " 
  which 
  were 
  noted 
  as 
  

   visible 
  in 
  the 
  scale 
  mounted 
  in 
  balsam 
  and 
  observed 
  on 
  

   the 
  flat, 
  but 
  it 
  may 
  be 
  doubted 
  whether 
  they 
  are 
  due 
  to 
  

   anything 
  more 
  than 
  irregularities 
  of 
  the 
  surface 
  of 
  the 
  

   lamina. 
  

  

  Transverse 
  sections 
  under 
  similar 
  treatment 
  show 
  cor- 
  

   responding 
  appearances. 
  In 
  those 
  sections 
  that 
  have 
  

   passed 
  transversely 
  through 
  the 
  central 
  substance, 
  the 
  

   clear 
  interval 
  between 
  this 
  substance 
  and 
  the 
  lower 
  layer 
  

   of 
  the 
  scale 
  is 
  readily 
  seen 
  ; 
  the 
  substance 
  itself 
  is 
  fusiform 
  

   in 
  outhne, 
  and 
  a 
  similar 
  or 
  more 
  marked 
  appearance 
  of 
  

   unstained 
  " 
  granules 
  " 
  occurs 
  at 
  each 
  extremity. 
  A 
  faint 
  

   beading 
  on 
  the 
  upper 
  layer 
  in 
  the 
  region 
  of 
  the 
  central 
  

   substance 
  indicates 
  the 
  delicate 
  ribs 
  seen 
  when 
  the 
  scale 
  

   is 
  examined 
  on 
  the 
  flat. 
  Both 
  beading 
  and 
  " 
  granules 
  " 
  

   are 
  probably 
  the 
  ridges 
  or 
  ribs 
  of 
  the 
  upper 
  surface 
  of 
  the 
  

   scale 
  in 
  cross 
  section. 
  In 
  a 
  few 
  cases 
  the 
  under 
  surface 
  

   of 
  the 
  cavity 
  containing 
  the 
  central 
  substance 
  appears 
  in 
  

   transverse 
  section 
  to 
  be 
  slightly 
  beaded. 
  The 
  nature 
  of 
  

   the 
  central 
  substance 
  is 
  uncertain, 
  but 
  the 
  appearance 
  it 
  

   presents 
  both 
  in 
  the 
  stained 
  and 
  unstained 
  condition 
  is 
  

   consonant 
  with 
  Dr. 
  Eltringham's 
  suggestion 
  that 
  it 
  repre- 
  

   sents 
  an 
  accumulation 
  of 
  dried 
  secretion. 
  

  

  In 
  scales 
  that 
  have 
  been 
  doubly 
  stained 
  in 
  light 
  green 
  

   and 
  safranin 
  and 
  mounted 
  in 
  Canada 
  balsam, 
  the 
  footstalk 
  

   and 
  accessory 
  disc 
  are 
  coloured 
  pink, 
  whereas 
  the 
  central 
  

   body, 
  as 
  before 
  noted, 
  is 
  stained 
  blue 
  or 
  greenish 
  blue. 
  

   The 
  latter 
  colour 
  is 
  also 
  generally 
  to 
  be 
  found 
  at 
  the 
  central 
  

   region 
  of 
  the 
  base 
  of 
  the 
  lamina, 
  this 
  being 
  the 
  part 
  which 
  

   marks 
  the 
  insertion 
  of 
  the 
  footstalk. 
  

  

  When 
  the 
  scale 
  is 
  examined 
  on 
  the 
  flat, 
  with 
  the 
  lower 
  

   surface 
  uppermost, 
  the 
  accessory 
  disc 
  is 
  usually 
  seen 
  to 
  

   be 
  superposed 
  upon 
  the 
  lamina, 
  the 
  footstalk 
  being 
  so 
  

   curved 
  as 
  to 
  bring 
  it 
  into 
  this 
  position. 
  If 
  the 
  upper 
  

  

  TRANS. 
  ENT. 
  SOC. 
  LOND. 
  1919. 
  — 
  PARTS 
  III, 
  IV. 
  (dEC.) 
  C 
  

  

  