NO,    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        21 
In  a  young  nymph,  Walker  (1922)  says,  the  ventral  intersegmental 
membrane  between  the  ninth  and  tenth  abdominal  segments  presents 
■"  two  oval,  slightly  elevated  areas  (fig.  6  A,  r,  I),  which  are  the  rudi- 
ments of  the  genital  lobes."  In  an  older  nymph  "  the  genital  lobes 
are  much  larger  and  are  separated  by  an  oblique  fissure,  as  in  the  adult, 
but  there  are  as  yet  no  chitinous  processes  nor  eversible  sac."  The 
genital  lobes  remain  distinct  in  the  adult  (B,  C,  D,  rPhm.  IPhm), 
-AcGlds 
rPhm 
Fig.  6. — Grylloblattoidea :  Male  genitalia  of  Grylloblalta  campodcifonnis 
Walker.  (A,  B,  C.  from  Walker,  1922;  D,  E,  from  unpublished  sketches  by 
Walker.) 
A,  half-grown  male  nymph,  showing  rudiments  of  phallic  lobes,  and  approxi- 
inate  symmetry  of  coxopodites  of  styli.  B,  C,  adult  male,  end  of  abdomen, 
right  and  left  sides.  D,  adult  male,  end  of  abdomen,  posterior  view,  showing 
genital  structures.   E,  internal  reproductive  organs  of  adult  male. 
a,  b,  thick  median,  and  more  slender  lateral  accessory  glands  (AcGlds)  ; 
Cer,  cercus;  C.vpd,  coxopodite  of  stylus;  Dej,  ductus  ejaculatorius  ;  Eppt,  epi- 
proct;  Gpr,  gonopore;  /,  rudiment  of  left  phallomere  (IPhm)  ;  Papt,  paraproct 
/'.  rudiment  of  right  phallomere  (rPhiii)  ;  sc,  saclike  phallic  lobe;  Sty,  stylus; 
Tes,  testis ;  tpl,  tpr,  left  and  right  ventral  processes  of  tenth  abdominal  tergum  ; 
Vd,  vas  deferens ;  x,  y,  z,  phallic  sclerites. 
and  the  gonopore  now  appears  as  a  small  aperture  (D,  Gpr)  on  the 
inner  margin  of  the  right  lobe.  The  latter  contains  three  prominent 
sclerites  on  its  upper  surface  {x,  y,  z)  ;  the  left  lobe  (IPhm)  is 
unsclerotized  except  for  a  small  setigerous  area  on  its  base,  but  it  is 
produced  into  a  long,  twisted  sac  (B,  C,  D,  sc). 
The  internal  genital  organs  of  the  male  are  shown  by  Walker  to 
have  a  very  simple  structure  as  compared  with  those  of  most  other 
Orthoptera.    "  The  testes  ",  Walker  writes,  "  are  simple  tubes   (fig. 
