26  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
(L,  IXS)  ;  the  venter  of  tlie  ninth  segment  posterior  to  the  sternum 
is  mostly  membranous,  being  formed  possibly  by  an  extension  of 
the  intersegmental  membrane.  The  large  subgenital  lobe  (C,  J,  L, 
IXSL)  is  scoop-shaped,  its  dorsal  concavity  forming  the  floor  of  the 
genital  chamber,  in  which  is  lodged  the  phallic  organ.  An  extreme 
development  of  this  type  of  structure  is  seen  in  DiapJieromcra  (L), 
in  which  the  sternal  plate  {IXS)  forms  a  small  supporting  stalk  for 
the  subgenital  lobe  {IXSL),  and  is  provided  with  two  pairs  of  large 
muscles  arising  on  the  tergal  plates  of  the  eighth  and  ninth  segments. 
The  phallic  organs  of  the  Phasmatidae  are  said  by  Chopard  (1920) 
to  consist  of  several  highly  variable  lobes,  and  of  a  very  much  reduced 
penis  entirely  concealed  by  the  lobes.  From  a  comparative  study  of 
the  more  simple  types  of  phallic  structures,  and  from  a  study  of  the 
development  of  the  genitalia  in  Cyphocrania  gigas,  Chopard  arrives 
at  the  following  generalization :  Fundamentally  there  are  four  very 
asymmetrical  genital  valves,  but  the  upper  two  are  often  united 
in  a  single  lobe;  the  valves  in  most  cases  are  membranous,  particu- 
larly the  lower  ones,  containing  only  small  sclerotic  areas  usually 
near  their  bases ;  sometimes,  however,  the  valves  are  strongly  sclero- 
tized,  and  in  such  cases  they  have  a  tendency  to  unite  in  two  large 
lobes,  one  dorsal,  the  other  ventral,  or  rarely  in  a  single  structure. 
The  illustrations  here  given  of  the  phasmatid  intromittent  organ 
include  examples  only  of  the  type  in  which  the  phallic  lobes  are 
more  or  less  united  to  form  a  single  structure  (fig.  8  G,  H,  I,  M,  N)  ; 
the  writer  is  not  familiar  with  forms  in  which  the  lobes  are  entirely 
distinct.  In  an  unidentified  species  (I)  the  phallus  is  a  soft,  ovate 
body  composed  of  several  irregular  lobes  of  different  sizes  united 
only  at  their  bases.  In  Anisomorpha  huprestoidcs  (G,  H)  the  lobes 
are  mostly  united,  being  free  only  at  their  tips,  which  converge  about 
the  gonotreme  on  the  ventral  surface  (H).  In  the  dorsal  wall  of  the 
phallus  is  a  weak  median  sclerite  (G,  e)  projecting  distally  in  a  small, 
free  process  on  the  left.  The  phallus  of  Diapheromera  femorata 
(M,  N)  is  a  thick  cylindrical  structure,  divided  apically  by  a  median 
cleft  into  short  right  and  left  lobes,  between  which  is  a  third  flat, 
median  lobe.  The  ejaculatory  duct  opens  here  between  the  bases  of 
the  lobes  ;  in  Anisonwrpha  it  opens  on  one  of  the  lobes  just  within 
the  lower  lip  of  the  gonotreme.  The  "  penis,"  said  by  Chopard  to  be 
concealed  within  the  phallic  lobes,  the  writer  has  not  observed. 
Chopard  points  out  that  the  lobiform  structure  and  asymmetry  of 
the  phasmatid  male  genitalia  give  the  organs  a  resemblance  to  the 
genital  lobes  of  male  Blattidae.  The  likeness  is  more  particularly 
evident   when  the  comparison   is   made  with  the   simpler   lobes   of 
