﻿344 
  Mr. 
  R. 
  I. 
  Pocock 
  on 
  some 
  

  

  Ehrenb., 
  the 
  British 
  Museum 
  possesses 
  others 
  from 
  Benguela 
  

   and 
  the 
  Congo 
  which 
  are 
  recognizable 
  at 
  a 
  glance 
  from 
  B. 
  

   liosoma 
  and 
  at 
  the 
  same 
  time 
  agree 
  precisely 
  with 
  the 
  

   elaborate 
  description 
  of 
  B. 
  villosus 
  set 
  forth 
  by 
  Dr. 
  Thorell. 
  

  

  Perhaps 
  the 
  most 
  noticeable 
  points 
  of 
  difference 
  are 
  to 
  be 
  

   found 
  in 
  the 
  form 
  of 
  the 
  tail. 
  This 
  organ 
  in 
  B. 
  villosus, 
  

   instead 
  of 
  being 
  dilated 
  from 
  the 
  first 
  to 
  the 
  fourth 
  segment, 
  

   as 
  in 
  B. 
  liosoma, 
  is 
  distinctly 
  wider 
  at 
  the 
  base, 
  the 
  fourth 
  

   segment 
  being 
  considerably 
  narrower 
  than 
  the 
  first. 
  More- 
  

   over, 
  while 
  in 
  B. 
  villosus 
  the 
  first 
  caudal 
  segment 
  is 
  above 
  

   more 
  fiat 
  than 
  it 
  is 
  in 
  B. 
  liosoma, 
  the 
  third, 
  fourth, 
  and 
  fifth 
  

   segments 
  in 
  the 
  former 
  are 
  more 
  deeply 
  excavated 
  than 
  in 
  

   the 
  latter 
  ; 
  the 
  superior 
  keels, 
  too, 
  are 
  more 
  dentate, 
  particu- 
  

   larly 
  on 
  the 
  fifth 
  segment 
  ; 
  the 
  vesicle 
  and 
  aculeus 
  are 
  

   larger. 
  The 
  colour 
  of 
  the 
  body 
  and 
  limbs 
  is 
  much 
  darker, 
  

   the 
  granules 
  coarser, 
  and, 
  above 
  all, 
  the 
  yellow 
  hairs 
  

   which 
  are 
  so 
  conspicuous 
  on 
  various 
  parts 
  of 
  the 
  body, 
  and 
  

   particularly 
  upon 
  the 
  tail, 
  in 
  B. 
  villosus 
  are 
  only 
  developed 
  

   in 
  B. 
  liosoma 
  to 
  a 
  relatively 
  small 
  extent. 
  

  

  In 
  fact 
  the 
  characters 
  of 
  the 
  two 
  are 
  sufficiently 
  well 
  

   marked 
  to 
  allow 
  us 
  to 
  regard 
  them 
  as 
  of 
  specific 
  importance. 
  

  

  Buthus 
  planicauda, 
  sp. 
  n. 
  (PI. 
  XV. 
  fig. 
  5.) 
  

  

  Colour 
  testaceous, 
  ochraceous, 
  or 
  ochraceo-rufous 
  ; 
  palpi 
  

   and 
  legs 
  paler 
  than 
  trunk 
  ; 
  the 
  last 
  three 
  segments 
  of 
  the 
  

   tail 
  may 
  be 
  slightly 
  deeper 
  in 
  colour 
  than 
  the 
  rest. 
  

  

  Female. 
  — 
  Cephalothorax 
  wider 
  behind 
  than 
  it 
  is 
  long, 
  

   much 
  narrowed 
  in 
  front 
  ; 
  anterior 
  width 
  about 
  half 
  its 
  poste- 
  

   rior 
  width 
  ; 
  marked 
  with 
  a 
  median 
  longitudinal 
  depres- 
  

   sion, 
  which 
  is 
  deeper 
  behind, 
  but 
  shallower 
  and 
  gradually 
  

   widened 
  in 
  front 
  ; 
  entirely 
  covered 
  with 
  close-set 
  granules 
  

   and 
  marked 
  with 
  shallow 
  lateral 
  depressions 
  ; 
  without 
  a 
  

   trace 
  of 
  keels. 
  Ocular 
  tubercle 
  lightly 
  hollowed, 
  granular 
  in 
  

   the 
  middle, 
  smooth 
  at 
  the 
  sides, 
  situated 
  in 
  front 
  of 
  the 
  

   middle 
  of 
  the 
  cephalothorax. 
  

  

  Tergites 
  finely 
  granular, 
  granules 
  coarser 
  upon 
  the 
  posterior 
  

   half; 
  each 
  of 
  the 
  first 
  six 
  marked 
  with 
  a 
  median 
  keel; 
  the 
  

   last 
  furnished 
  with 
  four 
  anteriorly 
  abbreviated 
  granular 
  keels, 
  

   its 
  upper 
  surface 
  shagreened. 
  

  

  Sternites 
  almost 
  wholly 
  smooth 
  ; 
  the 
  first 
  very 
  slightly 
  

   shagreened 
  beneath 
  the 
  pectines 
  on 
  its 
  extreme 
  antero-lateral 
  

   border 
  ; 
  the 
  last 
  finely 
  and 
  sparsely 
  granular 
  at 
  the 
  sides 
  and 
  

   furnished 
  with 
  four 
  slightly 
  roughened 
  keels. 
  

  

  Tail 
  almost 
  parallel-sided, 
  the 
  first 
  and 
  the 
  fourth 
  seg- 
  

   ments 
  being 
  equal 
  in 
  width 
  j 
  the 
  first 
  segment 
  fiat 
  above 
  

  

  