﻿The 
  Scent-scale 
  of 
  Pinacopteryx 
  liliana. 
  387 
  

  

  When 
  the 
  wing-membrane 
  of 
  P. 
  liliana 
  has 
  been 
  de- 
  

   nuded 
  of 
  scales, 
  three 
  kinds 
  of 
  socket 
  for 
  the 
  reception 
  of 
  

   the 
  footstalks 
  of 
  the 
  scales 
  come 
  into 
  view. 
  Those 
  for 
  

   the 
  ordinary 
  scales 
  are 
  simple 
  funnel-shaped 
  structures, 
  

   arranged 
  for 
  the 
  most 
  part 
  in 
  parallel 
  rows 
  nearly 
  at 
  

   right 
  angles 
  with 
  the 
  axis 
  of 
  the 
  wing, 
  and 
  differing 
  in 
  

   aspect 
  according 
  to 
  whether 
  they 
  belong 
  to 
  the 
  upper 
  or 
  

   lower 
  surface; 
  those 
  of 
  the 
  former 
  being 
  more 
  amply 
  

   surrounded 
  by 
  chitinous 
  folds 
  of 
  the 
  membrane, 
  and 
  so 
  

   presenting 
  a 
  darker 
  appearance. 
  In 
  addition 
  to 
  the 
  

   ordmary 
  sockets 
  on 
  the 
  upper 
  surface 
  may 
  also 
  be 
  seen 
  

   the 
  sockets 
  of 
  the 
  scent-scales. 
  These 
  hkewise 
  run 
  in 
  

   parallel 
  rows, 
  between 
  the 
  rows 
  of 
  ordinary 
  sockets. 
  They 
  

   are 
  fewer 
  in 
  number 
  than 
  the 
  latter 
  structures, 
  and 
  easily 
  

   to 
  be 
  distinguished 
  from 
  them 
  ; 
  being 
  larger 
  in 
  size, 
  broader 
  

   in 
  shape 
  and 
  darker 
  in 
  aspect 
  (PI. 
  XVI, 
  fig. 
  5,' 
  a, 
  b, 
  c). 
  

   Each 
  terminates 
  distally 
  in 
  a 
  transparent 
  crescentic 
  chitin- 
  

   ous 
  hp, 
  which 
  is 
  fringed 
  with 
  a 
  row 
  of 
  spiny 
  projections 
  

   radiating 
  from 
  its 
  convex 
  margin. 
  Proximally 
  to 
  the 
  

   fringed 
  hp 
  the 
  socket 
  shows 
  a 
  dark 
  opaque 
  area, 
  roughly 
  

   oval 
  or 
  circular, 
  which 
  shades 
  off 
  into 
  the 
  general 
  surlace 
  

   of 
  the 
  wing-membrane 
  by 
  a 
  number 
  of 
  striations, 
  parallel 
  

   with 
  the 
  long 
  axis 
  of 
  the 
  socket, 
  and 
  apparently 
  consti- 
  

   tuted 
  by 
  chitmous 
  folds. 
  In 
  longitudinal 
  sections 
  of 
  the 
  

   wmg-membrane, 
  the 
  funnel-shaped 
  contour 
  of 
  the 
  ordinary 
  

   sockets 
  of 
  both 
  upper 
  and 
  lower 
  surface 
  is 
  clearly 
  seen'; 
  

   it 
  can 
  also 
  be 
  recognised 
  that 
  the 
  former 
  are 
  set 
  at 
  a 
  some- 
  

   what 
  steeper 
  angle 
  to 
  the 
  membrane 
  than 
  the 
  latter 
  

   which 
  are 
  more 
  nearly 
  in 
  the 
  plane 
  of 
  the 
  wing 
  (PI. 
  XVI,' 
  

   fig. 
  2, 
  b, 
  c). 
  The 
  sockets 
  of 
  the 
  scent-scales 
  are 
  again 
  

   easily 
  distinguishable 
  by 
  their 
  larger 
  size 
  and 
  the 
  pro- 
  

   jecting 
  hp, 
  which 
  is 
  now 
  seen 
  in 
  profile 
  (fig. 
  2 
  d) 
  A 
  

   similar 
  Up 
  is 
  visible 
  on 
  the 
  side 
  of 
  the 
  socket 
  which 
  abuts 
  

   on 
  the 
  wmg-membrane 
  ; 
  the 
  latter, 
  however, 
  projects 
  from 
  

   the 
  mam 
  body 
  of 
  the 
  socket 
  to 
  a 
  much 
  smaller 
  extent 
  than 
  

   the 
  former 
  ; 
  it 
  also 
  appears 
  to 
  be 
  devoid 
  of 
  the 
  marginal 
  

   row 
  of 
  spines. 
  These 
  lips 
  may 
  be 
  called 
  "upper" 
  and 
  

   lower 
  respectively; 
  together 
  they 
  form 
  a 
  rim 
  which 
  

   appears 
  to 
  be 
  continuous 
  round 
  the 
  mouth 
  of 
  the 
  socket. 
  

   In 
  a 
  partially 
  denuded 
  wing 
  examined 
  on 
  the 
  flat 
  the 
  

   accessory 
  disc 
  of 
  each 
  scent-scale 
  is 
  seen 
  to 
  be 
  engaged 
  in 
  

   Its 
  appropriate 
  socket 
  (PI. 
  XVI, 
  fig. 
  6). 
  The 
  disc 
  is 
  

   much 
  larger 
  than 
  its 
  receptacle, 
  and 
  the 
  only 
  part 
  that 
  is 
  

   actually 
  included 
  within 
  that 
  structure 
  is 
  a 
  semicircular 
  

  

  