44  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
phallomere  is  the  large  genital  opening,  or  phallotreme  (Phtr).  Since 
the  terminal  part  of  the  genital  exit  passage  contains  a  sclerotization 
(es)  in  its  wall,  it  is  probably  a  phallic  invagination,  or  endophallic 
sac  (Enph),  rather  than  the  end  of  the  true  ductus  ejaculatorius 
(Dcj),  which  is  continuous  with  it. 
The  exposed  part  of  the  right  phallomere  comprises  an  oval  mem- 
branous lobe  on  the  right  (fig.  13  A,  B,  c),  and  a  flat  extension  on  the 
left  (/),  which  is  subdivided  into  a  sinistral  lobe  (a)  bearing  two 
strong  prongs  (d),  and  a  dextral  lobe  (b)  bearing  a  curved  spine  (c) 
turned  to  the  right.  From  the  base  of  the  phallomere  a  basal  plate  (o) 
extends  into  the  dextral  pocket  (y)  of  the  genital  chamber  wall, 
where  it  becomes  continuous  with  the  capsular  sclerite  (m)  of  the 
ventral  cavity,  and  supports  an  apodemal  plate  (p).  The  under 
surface  of  the  right  phallomere  (C)  contains  an  irregular  sclerotiza- 
tion {li,  i,  j,  k).  Proximal  to  the  latter  is  the  cavity  of  the  capsular 
sclerite  (in),  which  is  closed  in  the  usual  position  of  the  right  phal- 
lomere by  the  valvular  sclerite  («)  hinged  to  its  lower  lip. 
The  left  phallomere  (fig.  13  A,  IPhin,  D,  E)  is  a  fasces  of  irregular, 
elongate  lobes  (q.  r,  s,  f,  u) ,  free  at  their  extremities  but  having  a 
common  base  sunken  into  the  sinistral  pocket  (A,  s)  of  the  genital 
chamber.  A  large  oval  foramen  opens  into  the  base  of  the  phallomere 
(E)  from  the  body  cavity.  The  outermost  lobe  (A,  D,  q)  ter- 
minates in  a  strong  spearhead-shaped  process  (q')  turned  to  the  right, 
and  two  smaller  more  proximal  prongs  arise  from  the  median  lobes 
{t,u). 
The  ventral  phallomere  is  a  simple  broad  lobe  projecting  to  the 
right  from  beneath  the  right  phallomere  (fig.  13,  A,  vPhni).  The 
interphallic  fold  {fd)  containing  the  phallotreme  ends  on  its  upper 
surface  (fig.  14  B,  fd)  ;  its  lower  surface  is  a  flat  plate  (w)  with  a 
basal  arm  projecting  -to  the  left. 
The  phallic  musculature  of  Blatta  is  quite  difl^erent  from  that  of  the 
phasmid  Tcnodera  (fig.  10),  notwithstanding  the  evident  identity  of 
the  phallomeres  in  the  two  genera.  The  muscles  of  the  right  phal- 
lomere of  Blatta  (fig.  14  C)  include  the  following:  i,  a  short  thick 
muscle  from  the  left  side  of  the  ninth  abdominal  tergum  to  the  left 
extremity  of  the  phallomere  base ;  2,  j,  right  and  left  retractors  of  the 
phallomere,  arising  on  the  anterior  lobes  of  the  ninth  sternum  and 
converging  to  their  insertions  on  the  apodemal  plate  (fig.  13  A,  p) 
near  its  mesal  end ;  4^  a  muscle  arising  posteriorly  on  the  ninth  sternum, 
inserted  anteriorly  (fig.  14  C)  on  the  apex  of  the  apodemal  plate ; 
5,  a  large  muscle  from  the  apodemal  plate  to  the  capsular  sclerite  (w)  ; 
6,  a  long  muscle  from  the  apodemal  plate  to  the  basal  plate  (<?)  of 
