﻿Mr. 
  F. 
  Muir 
  on 
  Aedeagus 
  of 
  Habrocerus 
  capillaricornis. 
  399 
  

  

  In 
  Tachyporus 
  solutus 
  Erich., 
  the 
  ninth 
  segment 
  (figs. 
  1, 
  

   2, 
  3) 
  consists 
  of 
  four 
  pieces, 
  a 
  large 
  ovate 
  sternite 
  (ix), 
  a 
  

   pair 
  of 
  large 
  subtriangular 
  pleural 
  plates 
  {'p'p) 
  meeting 
  

   together 
  on 
  the 
  dorsal 
  aspect 
  and 
  overlapping 
  the 
  basal 
  

   portion 
  of 
  the 
  tergite 
  (9) 
  and 
  connected 
  by 
  a 
  slender 
  strip 
  

   on 
  the 
  ventral 
  aspect, 
  and 
  a 
  large 
  dorsal 
  plate 
  whose 
  basal 
  

   area 
  is 
  overlapped 
  by 
  the 
  pleural 
  plates. 
  In 
  Leistofrophus 
  

   we 
  find 
  a 
  similar 
  arrangement 
  of 
  segments, 
  but 
  the 
  ninth 
  

   differs 
  considerably 
  (figs. 
  4, 
  5). 
  The 
  pleural 
  plates 
  (pp) 
  

   are 
  small 
  and 
  each 
  bears 
  a 
  large 
  style 
  (s), 
  on 
  the 
  ventral 
  

   aspect 
  they 
  are 
  connected 
  by 
  a 
  narrow 
  strip 
  and 
  on 
  the 
  

   dorsal 
  aspect 
  they 
  are 
  widely 
  separated 
  by 
  the 
  large 
  

   tergite 
  ; 
  a 
  pair 
  of 
  large 
  glands 
  open 
  on 
  the 
  connecting 
  

   membrane 
  {a) 
  between 
  the 
  eighth 
  and 
  ninth 
  tergites. 
  

  

  What 
  is 
  here 
  considered 
  as 
  the 
  ninth 
  tergite 
  is 
  con- 
  

   sidered 
  by 
  some 
  writers 
  as 
  the 
  tenth 
  tergite, 
  but 
  we 
  can 
  

   see 
  no 
  morphological 
  reason 
  for 
  considering 
  it 
  so, 
  and 
  we 
  

   have 
  no 
  information 
  as 
  to 
  its 
  ontogeny. 
  The 
  anus 
  opens 
  

   beneath 
  the 
  ninth 
  tergite 
  on 
  a 
  membrane 
  which 
  connects 
  

   the 
  aedeagus 
  with 
  the 
  ninth 
  segment 
  {im 
  1). 
  

  

  Without 
  entering 
  into 
  a 
  comparative 
  study 
  of 
  the 
  ninth 
  

   abdominal 
  segment 
  we 
  can 
  consider 
  the 
  two 
  mentioned 
  as 
  

   typical 
  of 
  the 
  Staphylinidae. 
  

  

  In 
  Habrocerus 
  capiUaricornis 
  Grav., 
  the 
  first 
  tergite 
  is 
  

   well 
  defined, 
  between 
  it 
  and 
  the 
  second 
  there 
  is 
  a 
  fairly 
  

   large 
  membrane, 
  the 
  second 
  and 
  five 
  following 
  tergites 
  

   are 
  well 
  defined. 
  The 
  first 
  two 
  sternites 
  are 
  small 
  and 
  

   membranous, 
  the 
  following 
  five 
  are 
  well 
  defined. 
  The 
  

   seventh 
  segment 
  is 
  connected 
  by 
  a 
  large 
  membrane 
  to 
  the 
  

   sixth 
  some 
  distance 
  from 
  its 
  posterior 
  edge, 
  which 
  gives 
  

   the 
  seventh 
  great 
  mobility 
  and 
  allows 
  of 
  it 
  being 
  completely 
  

   withdrawn 
  into 
  the 
  sixth. 
  

  

  The 
  eighth 
  segment 
  (viii 
  in 
  figs. 
  6, 
  7, 
  8, 
  9) 
  is 
  highly 
  

   modified 
  and 
  consists 
  of 
  four 
  pieces. 
  A 
  large 
  pair 
  of 
  

   pleural 
  plates 
  {pp), 
  on 
  which 
  the 
  eighth 
  spiracles 
  (fig. 
  6, 
  sp) 
  

   are 
  situated, 
  embrace 
  the 
  lateral 
  area, 
  and 
  from 
  the 
  apex 
  

   of 
  each 
  a 
  large, 
  spine-like 
  style 
  arises 
  ; 
  the 
  dorsal 
  aspect 
  

   consists 
  of 
  a 
  very 
  short 
  tergite 
  (8), 
  and 
  the 
  sternite 
  (viii) 
  

   consists 
  of 
  a 
  large 
  plate 
  more 
  heavily 
  chitinised 
  round 
  the 
  

   edges, 
  the 
  posterior 
  portion 
  is 
  external 
  and 
  visible 
  and 
  has 
  a 
  

   small 
  emargination 
  in 
  the 
  middle, 
  the 
  rest 
  of 
  the 
  sternite 
  is 
  

   internal. 
  The 
  lateral 
  portion 
  of 
  the 
  eighth 
  tergite 
  articu- 
  

   lates 
  with 
  the 
  lateral 
  edges 
  of 
  the 
  sternite 
  and 
  also 
  articulates 
  

   in 
  a 
  depression 
  at 
  the 
  base 
  of 
  the 
  pleural 
  plates. 
  The 
  

  

  