﻿164 
  J. 
  W. 
  S. 
  MACFIE. 
  

  

  Postero-thoracic 
  setae 
  (fig. 
  2). 
  

  

  The 
  posterior 
  part 
  of 
  the 
  cephalo-thorax 
  is 
  readily 
  detached 
  as 
  a 
  separate 
  piece 
  

   which 
  is 
  concave 
  both 
  anteriorly, 
  where 
  it 
  fits 
  on 
  to 
  the 
  rest 
  of 
  the 
  cephalo-thorax, 
  

   and 
  posteriorly, 
  where 
  it 
  joins 
  the 
  first 
  abdominal 
  segment. 
  It 
  consists 
  of 
  two 
  

   lateral 
  triangular 
  plates 
  connected 
  by 
  a 
  narrow 
  central 
  bridge. 
  The 
  bridge 
  is 
  

   composed 
  of 
  a 
  small 
  quadrilateral 
  area 
  in 
  the 
  middle, 
  and 
  on 
  each 
  side 
  a 
  short 
  

   prolongation, 
  from 
  the 
  anterior 
  margin 
  of 
  which 
  arise 
  the 
  postero-thoracic 
  setae. 
  

   These 
  setae 
  are 
  directed 
  forwards 
  and 
  outwards. 
  There 
  are 
  three 
  postero-thoracic 
  

   setae, 
  namely 
  : 
  — 
  - 
  

  

  Internal 
  seta 
  (fig. 
  2, 
  8 
  ). 
  A 
  seta 
  of 
  moderate 
  size 
  and 
  strength 
  situated 
  close 
  to 
  

   the 
  outer 
  margin 
  of 
  the 
  quadrilateral 
  area 
  ; 
  usually 
  double, 
  sometimes 
  single 
  or 
  

   triple. 
  

  

  Median 
  seta 
  (fig. 
  2, 
  9 
  ). 
  A 
  stouter 
  and 
  longer 
  seta 
  situated 
  a 
  little 
  external 
  to 
  

   the 
  internal 
  seta 
  ; 
  single. 
  

  

  External 
  seta 
  (fig. 
  2, 
  10 
  ). 
  A 
  seta 
  of 
  moderate 
  size 
  and 
  strength 
  situated 
  a 
  little 
  

   external 
  to 
  the 
  median 
  seta 
  ; 
  single 
  or 
  double. 
  

  

  Abdominal 
  Setae. 
  

  

  The 
  majority 
  of 
  the 
  setae 
  of 
  the 
  pupa 
  are 
  attached 
  to 
  the 
  abdominal 
  segments 
  : 
  

   those 
  on 
  the 
  ventral 
  aspect 
  being 
  for 
  the 
  most 
  part 
  small 
  and 
  inconspicuous, 
  those 
  

   on 
  the 
  dorsal 
  and 
  lateral 
  aspects 
  being 
  more 
  highly 
  developed, 
  and 
  including 
  the 
  

   setae 
  of 
  greatest 
  systematic 
  importance. 
  

  

  Dorsal 
  abdominal 
  setae 
  (fig. 
  3). 
  

  

  The 
  dorsal 
  abdominal 
  setae 
  are 
  numerous, 
  and 
  are 
  mostly 
  situated 
  near 
  the 
  

   posterior 
  margins 
  of 
  the 
  segments. 
  With 
  them 
  may 
  be 
  ranked 
  the 
  lateral 
  setae, 
  

   which 
  are 
  of 
  importance 
  because 
  they 
  provide 
  convenient 
  means 
  for 
  specific 
  

   determinations, 
  and 
  the 
  setae 
  on 
  the 
  ends 
  of 
  the 
  paddles. 
  With 
  the 
  exception 
  

   of 
  the 
  setae 
  on 
  the 
  first 
  segment 
  all 
  the 
  abdominal 
  setae 
  are 
  directed 
  backwards. 
  

  

  Certain 
  of 
  the 
  dorsal 
  abdominal 
  setae 
  fall 
  naturally 
  into 
  series, 
  and 
  it 
  will 
  be 
  

   convenient 
  to 
  describe 
  all 
  the 
  setae 
  in 
  relation 
  to 
  them. 
  The 
  following 
  series 
  can 
  

   readily 
  be 
  recognised 
  : 
  — 
  

  

  1. 
  The 
  setae 
  composing 
  the 
  lateral 
  row 
  (fig. 
  3, 
  A). 
  These 
  are 
  especially 
  weL 
  

   developed 
  setae 
  situated 
  at, 
  or 
  slightly 
  anterior 
  and 
  internal 
  to, 
  the 
  posterior 
  angles 
  

   of 
  the 
  segments. 
  On 
  the 
  most 
  anterior 
  segments 
  they 
  are 
  slightly 
  ventral. 
  

  

  2. 
  A 
  series 
  of 
  delicate 
  setae 
  situated 
  close 
  by 
  and 
  internal 
  to 
  the 
  setae 
  of 
  the 
  

   lateral 
  row 
  (fig. 
  3, 
  A'). 
  

  

  3. 
  The 
  setae 
  composing 
  the 
  sub-median 
  row 
  (fig. 
  3, 
  C). 
  These 
  setae 
  are 
  

   situated 
  near 
  the 
  posterior 
  margin 
  of 
  the 
  segments 
  at 
  a 
  point 
  about 
  half-way 
  between 
  

   the 
  middle 
  line 
  and 
  the 
  posterior 
  angle. 
  

  

  4. 
  A 
  series 
  of 
  setae 
  situated 
  near 
  by 
  and 
  anterior 
  to 
  the 
  setae 
  of 
  the 
  sub-median 
  

   row 
  (fig. 
  3, 
  C, 
  C"). 
  

  

  5. 
  The 
  setae 
  composing 
  the 
  sub-lateral 
  row 
  (fig. 
  3, 
  B). 
  These 
  setae 
  are 
  situated 
  

   near 
  the 
  posterior 
  margins 
  of 
  the 
  segments 
  at 
  a 
  point 
  about 
  half-way 
  between 
  the 
  

   sub-median 
  row 
  and 
  the 
  posterior 
  angle. 
  

  

  