NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        75 
usual  lateral  phallic  lobes  appear  to  be  absent ;  the  ventral  lobe,  how- 
ever, is  well  developed  (figs.  22  F,  30  B,  vl),  and  beneath  it  is  a  sub- 
sidiary ventral  fold  (vf). 
In  Centhophilus  gracilipes  (fig.  30  A)  the  genital  region  of  the 
abdomen  is  concealed  above  the  large  hemispherical  sternal  plate  of 
the  ninth  segment  (IXS).  When  the  subgenital  sternum  is  depressed 
or  removed  the  phallus  may  be  seen  projecting  from  the  anterior  wall 
of  the  genital  chamber  as  a  large  body  (B)  with  a  deep  central  cavity, 
the  mouth  of  which  is  partly  occluded  by  a  thick,  tonguelike,  ventral 
\ohe  (vl).  Arched  above  the  opening  is  the  epiphallus.  This  structure, 
as  seen  from  behind  (B),  presents  an  elevated,  bilobed  median  part 
(e),  with  a  reflected  marginal  flange  (0),  which  is  produced  down- 
ward at  the  sides  of  the  phallic  opening  as  two  tapering  arms.  On 
the  dorsal  surface  of  the  phallus  (C)  the  epiphallus  includes  a  large 
median  plate  (in)  with  divergent  basal  extensions,  and  a  pair  of 
smaller  lateral  plates  (n).  There  are  no  lateral  phallic  lobes,  such  as 
those  always  present  in  Tettigoniidae,  but  the  ventral  lobe  (B,  D,  vl) 
is  well  developed  and  projects  upward  over  the  mouth  of  the  phallic 
cavity.  Beneath  the  ventral  lobe  is  an  accessory  ventral  fold  (vf)  of 
the  under  wall  of  the  phallus.  The  phallic  mouth  leads  into  an  ample, 
saclike,  dorsal  cavity  (D,  dc),  and  a  smaller,  ventral  endophallic 
cavity  (Ejipli),  the  two  separated  by  the  distal  margin  (g)  of  the 
floor  of  the  dorsal  cavity.  From  the  floor  of  the  dorsal  cavity  there 
arises  on  each  side  a  large,  thick,  soft  fold  (h),  which  is  probably 
distended  when  the  phallus  is  protruded.  The  inner  structure  of  the 
phallus  of  Centhophilus  is  thus  seen  to  be  the  same  as  that  shown 
diagrammatically  at  F  of  figure  22,  and  is  clearly  a  derivation  from 
the  usual  tettigoniid  type  given  at  D.  That  the  dorsal  fold  (e),  con- 
taining the  epiphallus,  is  a  production  of  the  anterior  margin  of  the 
dorsal  cavity  (fig.  22  D,  c)  is  evident  from  the  fact  that  in  Cett- 
thophilus  the  dorsal  retractors  of  the  phallus  (fig.  30  C,  D,  rpd)  are 
inserted  on  the  epiphallus. 
The  genitalia  of  Centhophilus  nhleri  (fig.  30  F)  are  only  partially 
concealed  by  the  ninth  abdominal  sternum,  which  here  is  a  large,  soft, 
bilobed  structure  {IXS)  little  resembling  an  ordinary  sternum. 
Between  the  sternal  lobes  are  seen  the  ventral  phallic  lobe  {vl),  and 
below  this  the  edge  of  the  accessory  ventral  fold  {vf).  Arched  over 
the  mouth  of  the  phallus  is  the  epiphallus  {e) ,  beneath  which  projects 
a  pair  of  soft,  cylindrical  papillae  {h)  that  arise  on  the  floor  of  the 
dorsal  cavity. 
Walker  (1922)  describes  the  genitalia  of  Ceuthophihis  lapidicola, 
C.  aridus,  and  C.  macnlatiis,  and  Gurney  (1936)  those  of  C.  brevipes. 
