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  IX. 
  The 
  Scent-scale 
  of 
  Pinacopteryx 
  liliana 
  Gr. 
  Smith. 
  

   By 
  F. 
  A. 
  DixEY, 
  M.A., 
  M.D., 
  F.E.S., 
  Subwardeii 
  

   of 
  Wadham 
  College, 
  Oxford. 
  

  

  [Read 
  June 
  4th, 
  1919.] 
  

  

  Plate 
  XVI. 
  

  

  In 
  a 
  recent 
  communication 
  on 
  the 
  charina 
  group 
  of 
  Pinaco- 
  

   pteryx* 
  mention 
  was 
  made 
  of 
  the 
  remarkable 
  scent-scale 
  

   of 
  P. 
  liliana 
  Gr. 
  Smith, 
  cJ. 
  It 
  is 
  now 
  proposed 
  to 
  give 
  a 
  

   fuller 
  account 
  of 
  this 
  structure, 
  so 
  far 
  as 
  its 
  details 
  can 
  be 
  

   made 
  out 
  in 
  the 
  absence 
  of 
  fresh 
  material. 
  

  

  As 
  has 
  been 
  elsewhere 
  recorded,! 
  ^^^ 
  outline 
  of 
  the 
  

   lamina 
  of 
  this 
  scale, 
  when 
  seen 
  on 
  the 
  flat, 
  resembles 
  that 
  

   of 
  the 
  thin 
  glass 
  flasks 
  used 
  in 
  chemical 
  laboratories 
  

   (PI. 
  XVI, 
  fig. 
  1). 
  At 
  the 
  junction 
  of 
  the 
  neck 
  with 
  the 
  

   body 
  of 
  the 
  flask 
  there 
  is 
  a 
  round 
  or 
  oval 
  granular 
  area 
  (a), 
  

   which 
  under 
  moderate 
  powers 
  of 
  the 
  microscope 
  appears 
  

   dark 
  by 
  transmitted 
  light, 
  and 
  usually 
  shows 
  a 
  com- 
  

   paratively 
  transparent, 
  highly 
  refracting, 
  roughly 
  circular 
  

   patch 
  in 
  the 
  middle. 
  The 
  proximal 
  part 
  of 
  the 
  lamina 
  is 
  

   marked 
  by 
  a 
  fine 
  longitudinal 
  ribbing, 
  which 
  loses 
  distinct- 
  

   ness 
  as 
  the 
  central 
  granular 
  area 
  is 
  reached. 
  Examined 
  

   with 
  a 
  yV-inch 
  immersion 
  lens, 
  each 
  rib 
  in 
  the 
  proximal 
  

   dilated 
  portion 
  of 
  the 
  lamina 
  has 
  a 
  varicose 
  appearance, 
  

   as 
  if 
  consisting 
  of 
  a 
  row 
  of 
  very 
  fine 
  granules 
  ; 
  these 
  rows 
  

   can 
  be 
  traced 
  with 
  some 
  difiiculty 
  through 
  the 
  central 
  

   area. 
  Beyond 
  the 
  central 
  area, 
  and 
  throughout 
  the 
  distal 
  

   portion 
  or 
  neck 
  of 
  the 
  lamina, 
  the 
  ribs 
  are 
  still 
  visible, 
  

   now 
  parallel 
  with 
  each 
  other 
  and 
  closer 
  together; 
  in 
  this 
  

   situation 
  the 
  ribs 
  are 
  finer 
  and 
  the 
  varicose 
  appearance 
  is 
  

   less 
  marked. 
  In 
  the 
  region 
  of 
  the 
  central 
  area, 
  numerous 
  

   additional 
  granules 
  come 
  into 
  view; 
  these 
  are 
  somewha;t 
  

   larger 
  than 
  the 
  rib-granules 
  and 
  are 
  irregularly 
  disposed. 
  

   Their 
  presence 
  tends 
  to 
  obscure 
  the 
  regular 
  ribbing 
  of 
  the 
  

   scale; 
  this, 
  however, 
  probably 
  persists 
  throughout 
  the 
  

   central 
  area, 
  being 
  continuous 
  in 
  fact 
  from 
  base 
  to 
  apex 
  

  

  * 
  Trans. 
  Ent. 
  Soc. 
  Lond., 
  1918, 
  p. 
  191. 
  

  

  t 
  Proc. 
  Ent. 
  Soc. 
  Lond., 
  1912, 
  p. 
  ex, 
  PI. 
  E, 
  fig. 
  10. 
  

  

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

  

  