NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS SNODGRASS        33 
hook  is  movable  by  a  large  muscle  (C,  6)  inserted  on  its  base.  This 
pincerlike  structure  is  said  by  Walker  (1922)  to  serve  as  a  clasper 
in  copulation,  the  remnant  of  a  male  abdomen  of  Stagmomantis  Caro- 
lina having  been  found  attached  by  it  to  the  female. 
The  left  phallomere  (fig.  10  D,  IPJnn)  has  a  more  complex  struc- 
ture than  the  right  phallomere.  It  consists  of  a  broad,  thick  basal 
lobe  and  of  three  large  terminal  processes  {g,  h,  i).  The  dorsal  wall 
of  this  appendage  is  derived  directly  from  the  anterior  wall  of  the 
genital  chamber,  but  its  ventral  wall  is  reflected  into  the  dorsal  wall 
of  the  ventral  phallomere  (D,  vPImi),  which  lies  beneath  it.  Of  the 
terminal  processes,  one  (D,  g)  is  a  strongly  sclerotic  arm  extending 
posteriorly  and  ending  in  an  upcurved  hook,  the  second  (h) ,  arising 
from  the  distal  end  of  a  plate  in  the  mesal  wall  of  the  appendage, 
is  a  broad  flat  lobe  turned  mesally,  the  third  (i)  is  a  weaker,  slender 
process  arising  beneath  the  second  and  curving  to  the  right  and 
dorsally.  Arising  proximally  from  the  mesal  plate  is  a  strong  hooklike 
process  (/)  that  normally  lies  in  a  pocket  on  the  imder  surface  of 
the  right  phallomere.  A  broad  tapering  apodemal  inflection  (k)  ex- 
tends inward  from  the  dorsal  margin  of  the  mesal  plate  to  give 
attachment  to  muscles  within  the  appendage,  but  the  left  phallomere 
has  no  basal  apodeme  corresponding  with  that  of  the  right  phallomere 
(E,  Ap).  A  short  apodemal  process  from  the  floor  of  the  left 
phallomere  (D,  in)  gives  insertion  to  several  convergent  muscles. 
The  ventral  phallomere  (fig.  10  F)  is  a  flat  appendage  of  irregular 
outline,  bearing  a  large  distal  process  (/)  curved  to  the  right.  Its 
long,  smooth  under  surface  fits  snugly  upon  the  concave  floor  of 
the  genital  chamber  ;  the  shorter  membranous  dorsal  wall  is  reflected 
into  the  ventral  wall  of  the  left  phallomere  (D),  so  that  the  basal 
parts  of  the  two  appendages  have  a  common  inner  cavity.  The  ven- 
tral wall  contains  a  large  plate  (F,  o).  The  distal  part  of  the  ventral 
phallomere  is  expanded  to  the  right,  forming  a  large  oval  lobe  with 
a  smooth  concave  surface  (n)  lying  usually  to  the  right  of  the  distal 
part  of  the  left  phallomere,  where  normally  it  is  covered  by  the  major 
lobe  of  the  right  phallomere  (B,  a).  At  the  base  of  the  concave  dorsal 
surface  of  the  ventral  phallomere  is  the  wide  funnel-shaped  opening 
(FGpr)  of  the  ejaculatory  duct  (Dej)  beneath  a  large  fimbriated  mem- 
branous fold  of  the  integument  (/>).  At  D  of  figure  10  the  ventral 
phallomere  is  shown  retracted  to  the  left,  in  which  position  it  is 
almost  completely  covered  by  the  left  phallomere,  but  ordinarily  its 
distal  lobe  (F,  w)  is  exposed  on  the  right  of  the  latter. 
The  phallic  musculature  of  Tenodera  is  highly  developed,  as  in 
Blatta  and  P enplane ta,  but  its  chief  interest  from  the  standpoint  of 
