l6  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
(Dej).  From  the  anterior  end  of  the  last  there  are  given  off  in  Embia 
major  about  i6  slender  accessory-gland  tubules  of  different  lengths 
(AcGlds)  arranged  in  two  lateral  groups.  In  Emhm  minor,  as  shown 
by  Mukerji,  there  is  a  similar  number  of  tubules,  but  one  tube  on 
each  side  is  particularly  long  and  is  much  thickened  in  its  anterior 
half.  Grassi  and  Sandias  find  only  four  tubules  in  Haplocmhia 
solicri,  which  they  describe  as  "  glandular  sacs."  Though  the  number 
of  accessory -gland  tubules  in  Embia  is  thus  variable  and  always  small 
as  compared  with  the  usual  number  in  Orthoptera,  the  number  of 
tubules  may  be  greater  than  in  Grylloblatta  (fig.  6E)  and  in  some 
of  the  Phasmatidae  (fig.  7  A,  C). 
The  external  genital  structures  of  male  Embiidae  are  well  known 
from  the  general  works  of  Verhoeff  (1904)  and  Enderlein  (1912), 
and  from  the  description  of  individual  species  by  Grassi  and  Sandias 
(1893,  1897-98),  Imms  (1913),  Crampton  (1918),  Walker  (1922), 
and  Mukerji  (1928).  A  true  phallic  organ  apparently  is  absent  or 
but  little  developed.  The  eleventh  abdominal  segment  is  suppressed 
in  the  male,  except  for  the  large  two-part  cerci,  which  are  generally 
asymmetrical,  and  may  have  large  basal  lobes  (fig.  4  D-H).  The 
external  genital  structures  consist  of  asymmetrical  modifications  of  the 
sternum  of  the  ninth  abdominal  segment  and  the  tergum  of  the  tenth 
'  segment,  and  of  lobes  and  processes  developed  from  these  parts  and 
from  the  bases  of  the  cerci.  The  least  modified  condition  occurs  in 
Clothoda  nobilis  (D,  E),  in  which  there  is  but  a  small  degree  of 
asymmetry.  The  ninth  and  tenth  terga  are  narrow  transverse  sclerites 
(D),  and  the  sternum  of  the  ninth  segment  (E)  is  an  entirely  sym- 
metrical plate  extended  posteriorly  in  a  median  lobe  {e)  beneath 
the  genital  opening.  The  bases  of  the  cerci  are  produced  mesally  as 
large  endite  processes  (D,  E.  d).  In  most  other  forms  the  tergum 
of  the  tenth  segment  is  subdivided  into  two  asymmetrical  lateral  plates, 
or  hemitergites  (F,  G,  Iht,  rht) ,  bearing  irregular  apical  processes 
{a,  b),  and  the  ninth  sternum  (H)  is  more  or  less  asymmetrically 
produced  to  the  left.  In  some  forms  the  base  of  the  left  cercus  is 
armed  with  a  large  irregular  endite  (G,  d).  It  is  to  be  noted  that 
all  the  accessory  genital  structures  converge  to  the  left,  and  that  it 
is  the  left  cercus  that  bears  a  basal  lobe  or  is  otherwise  modified. 
The  sinistral  development  of  the  genital  parts  is  an  adaptation  to  the 
relative  position  of  the  male  and  female  during  copulation. 
The  mating  habits  of  embiids  have  been  noted  by  Melander  (1903) 
in  Oligotoma  texana,  and  more  fully  described  by  Friederichs  (1934) 
in  Oligotoma  nigra  and  Monotylota  ramburi.  The  male  of  Embia  or 
Oligotoma  places  himself  on  the  back  of  the  female,  with  his  abdomen 
