NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        63 
large,  thick,  soft  body  arising  from  the  anterior  wall  of  the  chamber. 
Its  general  structure  may  be  represented  diagrammatically  as  at  C, 
figure  22.  The  posterior  part  of  the  organ  presents  ventrally  a  wide 
transverse  opening,  the  phallotreme,  which  leads  into  a  large  ventral 
endophallic  cavity  (Enph)  continuous  anteriorly  with  the  ejaculatory 
duct.  The  part  of  the  organ  above  the  phallotreme  constitutes  a  large. 
A      ^^'  Bn'p^ 
.-41 
C    II  ^^p 
l^    vi 
Y)   X    Enph 
Fig.  22. — Diagrams  showing  the  fundamental  structure  and  the  evolution 
of  the  tettigonioid  tj'pe  of  phallus  in  Tettigoniidae  and  Rhaphidophorinae. 
A,  nymphal  structure  of  the  phallus,  postero-lateral  view.  B,  same,  median 
section.  C,  adult  structure  of  the  phallus  in  Tettigoniidae,  postero-lateral  view. 
D,  same,  median  section.  E,  same,  dorsal  cavity  and  its  armature  everted.  F, 
adult  structure  of  the  phallus  in  Rhaphidophorinae,  median  section. 
The  following  letter  explanations  apply  to  figs.  22  to  28,  inclusive.  An, 
anus ;  AcGlds,  accessory  glands ;  Ccr,  cercus ;  dc,  dorsal  cavity  of  phallus ;  Dcj, 
ductus  ejaculatorius;  dl,  dorsal  lobe  of  phallus;  e,  anterior  margin  of  dorsal 
cavity  of  phallus  (produced  posteriorly  at  F)  ;  ejv,  vesicle  of  ejaculatory  duct; 
Enph.  endophallus;  Epdni,  epididymis;  Eppt,  epiproct;  /,  lateral  margin  of 
dorsal  cavity  of  phallus ;  g,  posterior  margin  of  dorsal  lobe  of  phallus ;  h,  mem- 
branous lobe  or  fold  on  floor  of  dorsal  cavity  of  phallus ;  i,  sclerotic  armature 
associated  with  h;  j,  dorsal  fold  of  body  wall  above  base  of  phallus;  k,  dorsal 
pouch  of  phallus  formed  Dy  posterior  reflection  of  anterior  margin  (e)  of 
dorsal  phallic  cavity  (dc)  ;  II,  lateral  lobe  of  phallus;  nicl,  muscles;  Papt,  para- 
proct:  Phi,  phallus;  Phtr,  phallotreme;  PSh,  peritoneal  sheath  of  testis;  rpd, 
rpv,  dorsal  and  ventral  retractor  muscles  of  phallus ;  ST,  sperm  tube  of  testis ; 
Sty,  stylus ;  Tes,  testis ;  Vd,  vas  deferens ;  vj,  ventral  fold  of  phallus ;  vl,  ventral 
lobe  of  phallus;  x-x,  cut  edge  of  anterior  wall  of  genital  chamber;  X.V,  venter 
of  tenth  abdominal  segment. 
thick  dorsal  lobe  (dl),  the  part  beneath  projects  as  a  broad,  flaplike 
ventral  lobe  (vl) ,  while  at  each  side  of  the  opening  is  a  lateral  lobe 
(II).  The  upper  or  posterodorsal  surface  of  the  dorsal  lobe  is  usually 
depressed  or  deeply  sunken,  forming  a  dorsal  cavity  (dc),  the  margins 
of  which  (e,  f,  g)  are  often  prominent  folds.  The  distal  margin  (g) 
appears  as  a  transverse  septimi  between  the  dorsal  cavity  and  the 
mouth  of  the  endophallic  cavity.    The  floor  of  the  dorsal  cavit)'-  is 
