52  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
The  female  genitalia. — The  external  genital  structures  of  female 
Blattidae  include  the  opening  of  the  median  oviduct,  the  aperture  of 
the  spermatheca,  the  ovipositor,  the  opening  of  the  accessory  glands, 
and  the  oothecal  mold ;  they  involve  the  seventh  abdominal  sternum 
and  the  ventral  parts  of  at  least  the  eighth  and  ninth  abdominal  seg- 
ments. The  genitalia  are  completely  concealed  in  a  large  cavity  above 
the  seventh  sternum,  which  latter  is  prolonged  beneath  the  ventral 
parts  of  the  succeeding  segments.  The  short  ovipositor  arises  (in  the 
adult)  from  the  venter  of  the  ninth  segment  in  the  dorsal  wall  of  the 
cavity.  The  small  anterior  part  of  the  cavity  lying  before  the  ovi- 
positor and  above  a  fold  representing  the  eighth  sternum  corresponds 
with  the  usual  genital  chamber  of  the  eighth  segment  (see  Snodgrass, 
1933,  fig.  23)  ;  the  much  larger  posterior  part,  or  vestibule,  lying  above 
the  seventh  sternum  contains  the  ovipositor  anteriorly,  and  forms 
distally  a  mold  and  container  for  the  ootheca.  The  opening  of  the 
oviduct  (gonopore)  lies  on  a  fold  or  lobe  of  the  venter  of  the  eighth 
segment,  the  spermatheca  opens  somewhere  between  the  gonopore  and 
the  ovipositor,  and  the  accessory  glands  discharge  behind  the  base  of 
the  ovipositor. 
The  spermatheca  of  Blattidae  is  a  two-branched  structure  (figs.  1 1  I, 
15  F),  one  branch,  which  is  usually  thicker  than  the  other  or  enlarged 
at  the  end,  being  the  true  sperm  receptacle,  the  other  apparently  a 
glandular  accessory.  In  Blatta  and  Pcriplancta  there  is  but  one 
spermatheca;  in  Blattella  there  are  two  complete  spermathecae  (fig, 
19  B),  each  with  a  separate  opening  and  a  glandular  branch.  Ac- 
cording to  Cleveland  (1934)  two  spermathecae  are  present  also  in 
Cryptocercus  punctidatns.  The  larger  branch  of  the  spermatheca  of 
Blatta  orientalis  (fig.  ill,  Spt)  is  traversed  by  a  narrow  axial  canal 
with  strongly  sclerotic  walls,  from  which  are  given  off  numerous 
fine  canaliculi  into  the  cells  of  the  thick  glandular  epithelium.  In  a 
preliminary  study  the  writer  mistook  these  threadlike  ductules  for 
spermatozoa,  and  made  the  foolish  statement  that  the  supposed  sper- 
matozoa are  attached  to  a  long  spermatophore  (Snodgrass,  1936, 
p.  90).  Ito  (1924),  however,  has  shown  the  true  nature  of  the  struc- 
tures radiating  from  the  central  canal.  He  says,  moreover,  that  the 
lumen  of  the  spermatheca,  after  copulation,  is  filled  with  spermatozoa 
and  fine  granules  of  secretion.  The  spermatheca  of  Blatta  and  of  Peri- 
planeta  opens  upon  a  small  papilla  on  a  median  sclerite  in  the  dorsal 
wall  of  the  genital  chamber  (figs.  11  F,  G,  15  G,  Spr)  proximal  to  the 
base  of  the  ovipositor.  In  Blattella  the  spermathecae  have  quite  a 
different  position,  as  will  be  shown  later,  and  their  openings  have  a 
very  special  relation  to  the  gonopore. 
