NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        3I 
segments,  consist  each  of  numerous  sperm  tubes  invested  in  a  deli- 
cate peritoneal  sheath.  The  vasa  deferentia  run  caudad  from  the 
testes  as  simple  tubes  with  a  few  convolutions,  turn  mesad  beneath 
the  cereal  nerves,  and  then  go  forward  to  the  ductus  ejaculatorius. 
which  they  enter  at  the  base  of  a  bilobed  anterior  swelling  of  the 
latter  (B).  This  anterior  enlarged  part  of  the  ejaculatory  duct  prob- 
ably represents  the  united  mesodermal  ampullae  of  the  primitive  exit 
system ;  from  it  are  given  off  the  tubules  of  the  accessory  glands 
(AcGlcis),  and  the  pair  of  globular  sperm  vesicles  (Vsvi),  which 
normally  are  concealed  among  the  gland  tubules.  The  numerous 
tubules  of  the  accessory  glands  are  of  different  lengths,  but  are 
approximately  of  the  same  diameter,  and  appear  to  be  all  of  a  like 
nature  functionally.  The  ectodermal  part  of  the  ductus  ejaculatorius 
is  a  wide  tube  extending  straight  backward  to  the  base  of  the  ventral 
phallomere,  on  the  dorsal  surface  of  which  it  opens  between  mem- 
branous folds  (fig.  10  F,  Gpr).  The  phallic  gland  (A,  PhGld) 
lies  on  the  posterior  part  of  the  mass  of  accessory  gland  tubules,  at 
the  left  of  the  ejaculatory  duct ;  it  is  subdivided  into  several  irregular 
lobules,  but  posteriorly  is  continued  as  a  tapering  duct  into  the  left 
phallomere  to  open  on  the  distal  part  of  the  latter. 
The  external  genitalia. — The  external  genital  organs  of  Tenodera 
sinensis,  as  already  noted,  consist  of  three  large  irregular  genital  lobes, 
or  phallomeres  (fig.  loA,  IPhni,  rPJiin,  vPhui),  which,  as  in  Blatta 
and  Periplancta.  enclose  the  gonopore  between  them  but  do  not  form 
a  unified  phallic  structure.  Two  of  the  phallomeres  arise  respectively 
right  and  left  above  the  genital  opening,  the  third  is  median  and 
ventral. 
The  right  phallomere  (fig.  10  B)  is  a  wide  flat  appendage  of 
triangular  form  with  a  long  transverse  base  extending  to  the  left 
above  the  base  of  the  left  phallomere  in  the  anterior  wall  of  the  genital 
chamber.  The  distal  margin  is  produced  into  a  large  lobe  {a)  on  the 
right  and  a  smaller  lobe  {c)  on  the  left.  On  the  under  surface  of 
the  appendage,  along  the  proximal  part  of  the  lateral  margin  of  the 
ventral  wall,  is  a  slender,  strongly  sclerotized  bar  forming  a  serrated 
ridge  (C,  E.  d),  from  the  proximal  end  of  which  an  arm  {e)  ex- 
tends laterad  and  supports  a  large  apodeme  (B,  C,  E,  Ap).  The 
apodeme  projects  forward  on  the  right  into  the  body  cavity  of  the 
ninth  and  eighth  segments  of  the  abdomen,  and  expands  into  a  flat 
plate  (E)  over  the  anterior  end  of  the  eighth  sternum.  Just  mesad 
of  the  proximal  end  of  the  serrated  ridge  there  arises  from  the  wall 
of  the  genital  chamber  a  strong  hooklike  process  (C,  E,  /)  articulated 
basally  on  the  ridge  and  having  its  apex  opposed  to  the  latter.   The 
