351 
side,  but  not  horizontal,  the  upper  surface  almost  following  the 
slope  of  the  dorsal  surface;  those  of  the  5th  and  6th  directed  slightly 
forwards,  from  the  6th  to  the  end  produced  gradually  more  and 
more  backwards;  the  anterior  borders  very  lightly  convex,  the 
posterior  being  correspondingly  concave,  both  very  finely  serrate,  the 
lateral  margin  very  lightly  convex  or  straight  and  only  very  lightly 
lobate,  the  anterior  angle  obtusely  convex  posteriorly,  the  posterior 
angle  acute  and  spiniform  but  not  strongly  produced.  The  whole  of 
the  upper  surface  of  the  body  covered  with  low  smooth  granulation ,  with 
larger  granules  along  the  hinder  border,  and  very  indistinct  traces  of  two 
other  series  in  front.  The  pores  situated  about  1  a  mm.  from  the  side 
margin.  The  caudal  'process  with  convex,  obsoletely  lobate  posterior  bor- 
der. The  lateral  surface  of  the  body  granular.  Sterna  with  a  transverse 
groove,  anteriorly  and  posteriorly  emarginate;  not  armed  with  spines. 
cT.  More  slender  than  the  9  and  much  less  convex.  Copulatory  foot 
terminating  in  two  slender  pointed ,  curved ,  processes ,  of  which  the 
inferior  curves  downwards  and  backwards  and  the  superior  inwards 
and  backwards. 
9  Length  about  75  mm.;  width  in  of  10th  segment  12.5;  width  of 
1st  segment  6.5;  of  2**  9;  length  of  1st  3.5. 
46.  Platyrhachus  weberi,  sp.  n.  Pl.  XX,  fig.  9— 9\ 
Sumatra:  Ajer  Mantjur. 
Colour:  head  and  antennae  black;  somites  black,  keels  in  front  and 
behind  yellowish  white,  black  at  the  base,  the  black  or  brown  colour 
spreading  along  the  middle  almost  to  the  lateral  margin  :  legs  fuscous, 
paler  at  the  base. 
Head  granular  above.  Ântennœ  long. 
First  tergite  elliptical,  nearly  flat,  about  twice  as  wide  as  long, 
with  distinct  keels  directed  obliquely  upwards  and  backwards ,  rugulose 
above,  with  an  indistinct  series  of  tubercles  along  the.  anterior  and 
posterior  border.  The  2**  and  3rd  with  their  keels  directed  obliquely 
forwards,  the  plane  of  the  keels  being  directed  downwards  and  for- 
wards, the  angles  rounded  and  the  margins  entire;  keels  of  4th  hori- 
zontal, projecting  at  right  angles  to  the  long  axis  of  the  body,  its 
angles  rounded  and  its  lateral  border  lightly  emarginate.  The  keels  of 
the  rest  situated  near  the  summit  of  the  side,  horizontal,  from  the 
