88 
prove  to  be  of  but  little  importance  when  large  series  of  specimens  have 
been  examined.  Mr.  C.  Hose  has  also  recently  sent  to  the  museum 
from  Mt.  Dulit  in  Borneo,  a  second  specimen  which  in  part  bridges 
over  the  interval  between  the  two  species  here  under  discussion.  This 
specimen  is  52  mm.  long,  has  21  pectinal  teeth,  and  four  keels  on  the 
last  abdominal  sternite  —  thus  agreeing  with  hosei.  But  in  colouring 
it  comes  somewhat  between  the  two,  although  differing  a  little  from 
both;  for  the  vesicle,  hands  and  fingers  are  yellow,  the  fingers  being 
only  very  slightly  darker  than  the  hand.  In  other  respects,  however, 
the  colouring  is  that  of  hosei,  except  that  the  tarsi  are  yellower. 
(Isometrus  s.  s.) 
3.  Isometrus  maculatus  (De  Geer). 
Specimens  of  this  wide-spread  species  were  obtained  at  Buitenzorg. 
4.  Isometrus  formosus  sp.  n.  (Pl.  VI,  fig.  3  — 3c). 
Java:  Buitenzorg.  15  specimens,  all  of  which  appear  to  be  females. 
Colour  ochraceo-fuscous  or  flavo-fuscous  above,  paler  beneath;  cépha- 
lothorax with  the  area  around  and  in  front  of  the  central  eyes  entirely 
fuscous,  the  rest  of  it  ochraceo-fuscous,  with  a  clearer  ochraceous  spot 
on  the  posterior  angle  on  each  side;  tergites,  except  the  last,  marked 
posteriorly  on  each  side  with  two,  one  lateral  and  one  median,  clearer 
ochraceous  marginal  spots,  and  a  <  shaped  ochraceous  patch,  the  ex- 
ternal margin  of  each  fulvous  and  bounded  internally  by  a  fuscous  band 
the  last  tergite  fusco-lineate  ;  lower  surface  of  the  trunk  entirely  pale 
except  for  two  feeble  fuscous  spots  on  the  posterior  half  of  the  5th  ster- 
nite ;  tail  with  the  first  three  segments  above  anteriorly  ochraceous  and 
posteriorly  fuscous,  spotted  and  lined  with  fuscous  beneath,  the  fourth 
and  fifth  segments  and  vesicle  rufo-fuscous  in  front  passing  imperceptibly 
into  fuscous  behind;  humerus  marked  above  with  two  fuscous  bands, 
pale  beneath,  brachium  almost  entirely  fuscous  above,  its  proximal 
extremity  only  flavous,  fuscescent  beneath;  manus  flavous,  fusco- 
maculate  and  lineate  externally,  digits  with  the  distal  half  fuscous  and 
the  proximal  rufo-fuscous;  legs  externally  banded  with  fuscous. 
Céphalothorax  closely  and  somewhat  coarsely  granular  throughout; 
the  anterior  border  widely  emarginate;  ocular  tubercle  widely  sulcate 
and  finely  granular. 
