NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS- — SNODGRASS        Ol 
The  musculature  of  the  phallus  comprises  intrinsic  muscles  of  the 
dorsal  pouch  (figs.  32  B,  34  D,  i,  2)  and  the  ventral  lobe,  and  several 
pairs  of  extrinsic  muscles.  The  latter  (fig.  34  D)  include  two  pairs  of 
muscles  arising  from  the  anterior  angles  of  the  ninth  abdominal 
sternum,  one  pair  (j)  inserted  on  the  lower  ends  of  the  lateral 
sclerites  in  the  base  of  the  phallus,  the  other  (,/)  on  the  base  of  the 
lateral  walls  of  the  dorsal  lobe.  Dorsal  phallic  muscles  from  the  tenth 
tergum,  such  as  are  present  in  the  tettigoniids,  appear  to  be  absent 
in  Grylhis.  The  phallus  is  innervated  from  a  nerve  trunk  (D,  XNv) 
that  branches  from  the  base  of  the  large  cereal  nerve  (XINv),  and 
appears  to  belong  to  the  tenth  abdominal  segment,  since  it  certainly 
does  not  pertain  to  either  the  ninth  or  the  eleventh  segment. 
The  dorsal  phallic  pouch  of  Grylhis  assimilis  has  a  thin,  membranous 
inner  wall,  but  it  is  covered  externally  by  a  muscular  sheath  of  trans- 
verse fibers  (figs.  32  B,  34  D,  /).  Though,  as  above  noted,  it  has  no 
armature  arising  from  its  floor  as  in  Tettigoniidae  and  Rhaphidophor- 
inae,  it  has  other  structures  adapting  it  to  its  function  of  forming  and 
holding  the  spermatophore  and  inserting  the  spermatophore  duct.  On 
the  floor  of  the  pouch  is  a  thickened  median  plate  (fig.  32  E,  w), 
having  its  proximal  angles  at  the  ventral  lip  of  the  pouch  (g)  pro- 
duced as  a  pair  of  triangular  lateral  expansions,  and  its  distal  part 
furrowed  by  a  median  depression  and  two  lateral  grooves.  The 
distal  end  of  the  plate  is  continued  in  a  troughlike  fold  (u)  with  a 
median  groove  that  extends  up\A'ard  and  then  posteriorly  in  the  anterior 
and  dorsal  walls  of  the  pouch,  and  ends  with  a  long,  free,  tapering, 
virgalike  rod  (E,  D,  v)  that  projects  from  the  wall  of  the  pouch 
beneath  the  epiphallus.  The  axial  groove  of  the  fold  is  continuous 
from  the  distal  depression  of  the  ventral  plate  to  the  tip  of  the  terminal 
rod  (D,  v).  The  base  of  the  rod  is  supported  by  a  W-shaped  sclerite 
in  the  dorsal  wall  of  the  pouch  (figs.  32  B,  D,  34  D,  t),  on  the  median 
part  of  which  is  inserted  a  pair  of  broad  muscles  (fig.  34  D,  2) 
converging  from  the  lateral  parts  of  the  epiphallus.  The  inner  struc- 
tures of  the  dorsal  sac  are  clearly  the  molds  of  the  attachment  plate 
and  the  duct  of  the  spermatophore,  since  the  shape  and  contour  of  the 
attachment  plate  (fig.  32  G,  y)  fit  exactly  the  form  and  depressions  of 
the  ventral  plate  of  the  pouch,  and  the  long,  recurved,  tapering  duct 
of  the  spermatophore  (dcf)  follows  the  groove  of  the  fold  (D,  n) 
and  the  terminal  rod  (v) . 
Walker  (1922)  in  his  description  of  the  phallic  structure  of  Gryllus 
calls  the  dorsal  cavity  the  "  spermatophore  sac  '',  though  he  observes 
that  it  would  appear  at  first  sight  that  the  dorsal  sac  of  Gryllus  is  the 
paramere  sac  (i.  e.,  dorsal  sac)  of  Tettigoniidae.    This  view,  which 
