62  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
Sternum  of  the  adult  male  has  a  very  unusual  form  (A,  C,  IXS)  ;  it 
folds  up  against  the  end  of  the  abdomen  and  bears  a  large  hammer- 
shaped  process  (sp)  on  its  under  surface.  Walker  (1922)  gives  a 
good  illustration  of  the  terminal  aspect  of  the  abdomen  of  Cyphoderris 
monstrosa,  and  he  says  the  only  representative  of  the  penis  are  the 
folded  membranous  lips  of  the  genital  passage.  This  statement  is 
entirely  true,  but  when  the  membranous  folds  are  inflated,  as  shown 
at  B  of  figure  21,  drawn  from  a  dried  specimen  boiled  in  water, 
they  take  the  form  of  a  definite  organ,  the  lips  of  which  are  produced 
into  a  number  of  lobes  surrounding  the  gonotreme,  which  opens  from 
a  spacious  endophallic  cavity. 
The  structure  of  the  phallus  of  Cyphoderris  is  easily  understood 
on  examining  the  organ  in  a  late  nymphal  stage.  The  nymphal  phallus 
(fig.  21,  G,  H,  I)  is  a  broad,  flat  structure  with  weakly  sclerotized 
walls,  arising  by  a  wide  base  from  the  wall  of  the  genital  chamber. 
It  contains  a  large  endophallic  cavity,  to  the  anterior  wall  of  which 
is  attached  the  ejaculatory  duct  (G,  Dej).  The  lips  of  the  phallotreme 
are  subdivided  into  several  distinct  lobes;  above  is  a  broad  dorsal 
lobe  (G,  H,  dl),  at  the  sides  a  pair  of  oval  lateral  lobes  (//),  and 
below  a  pair  of  ventral  lobes  (H,  I,  vl),  each  subdivided  into  two 
parts.  The  structure  of  the  nymphal  phallus  of  Cyphoderris  is  typical 
of  that  of  the  Tettigonioidea  in  general  (figs.  23  B-F,  31  F-H).  The 
dififerentiation  of  the  organ  into  its  various  adult  forms  takes  place 
principally  with  the  change  to  the  imago. 
In  the  phallus  of  the  adult  Cyphoderris  (fig.  21  B)  the  various  lobes 
of  the  nymphal  organ  (H)  have  expanded  into  large  vesicular  proc- 
esses, which  are  probably  distended  by  pressure  from  within  the 
abdomen.  The  ventral  lobes  {vl)  now  include  five  subsidiary  lobes, 
but  the  median  one  is  evidently  the  small  median  part  between  the 
ventral  lobes  of  the  nymph  (I).  At  the  sides  of  the  phallotreme  are 
the  greatly  expanded  lateral  lobes  (//).  The  dorsal  lobe  {dl)  carries 
two  marginal  vesicles,  and  its  median  part  is  deeply  depressed,  forming 
a  dorsal  cavity  {do),  but  its  distal  margin  {g)  is  still  the  upper  lip  of 
the  phallotreme.  The  latter  leads  into  an  ample  endophallic  cavity 
that  receives  the  ejaculatory  duct. 
Tettigoniidae. — The  phallus  of  the  tettigoniids  in  its  essential  struc- 
ture and  immature  form  is  identical  with  that  of  Cyphoderris,  but  in  its 
adult  development  it  is  subject  to  greater  modifications.  The  structural 
variations  of  the  adult  organ,  however,  are  but  little  divergent  and 
closely  follow  a  single  line  of  evolution. 
The  mature  tettigoniid  phallus  in  its  usual  retracted  condition  is 
mostly  concealed  within  the  genital  chamber,  where  it  appears  as  a 
