NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        95 
The  innervation  of  the  distal  segments  of  the  abdomen  as  shown 
in  Scapteriscus  (fig.  39  B)  ilhistrates  well  the  typical  relation  of  the 
segmental  nerves  to  the  genital  organs  in  Orthoptera.  The  last  ventral 
ganglion  innervates  segments  VII  to  A7.  The  lateral  nerves  of  the 
first  three  of  these  segments  in  the  male  go  beneath  the  vasa  deferentia 
(or  the  epididymes),  and  the  nerves  of  the  tenth  segment  (XNv) 
would  do  so  if  brought  forward.    The  large  cereal  nerves  of  the 
Epdm 
Fig.  39. — Tettigonioidea-Gryllotalpidae :  internal  male  genitalia  and  associated 
organs  of  Gryllotalpa  and  Scapteriscus. 
A,  Gryllotalpa  hexadactyla  Perty,  internal  organs  of  reproduction,  dorsal  view. 
B,  Scapteriscus  vicimis  Scudder,  internal  organs  of  terminal  part  of  abdomen, 
ventral  view. 
The  following  letter  explanations  apply  to  figs,  ^g  and  40.  AcGlds,  accessory 
glands;  An,  anus:  AnGld,  anal  gland;  Ccr,  cercus;  d,  body  of  very  small  gland 
tubules;  Dej,  ductus  ejaculatorius ;  ejv,  vesicle  of  ejaculatory  duct;  Epdm, 
epididymis ;  Eppt,  epiproct ;  GC,  genital  chamber ;  Ode,  oviductus  communis ; 
Odl,  oviductus  lateralis;  Oz^,  ovary;  Papt,  paraproct;  PhGld,  phallic  gland; 
Phi,  phallus ;  PhNv,  phallic  nerve  ;  Rcct,  rectum ;  Tes,  testis ;  Vd,  vas  deferens ; 
Vsm,  vesicula  seminalis ;  x,  wall  of  genital  chamber;  VIINv-XlNv,  segmental 
nerves  of  seventh  to  eleventh  abdominal  segments. 
eleventh  segment  (XINv),  however,  go  dorsal  to  the  vasa  deferentia, 
which  loop  forward  beneath  them  to  join  the  ductus  ejaculatorius. 
This  relation  between  the  segmental  nerves  and  the  male  genital  ducts 
is  possible  only  on  the  condition  that  the  primitive  vasa  deferentia 
turned  downward  and  united  with  the  body  wall  somewhere  between 
the  tenth  and  eleventh  nerves,  and  therefore  probably  on  the  posterior 
part  of  the  tenth  abdominal  segment.  The  nerves  of  the  tenth  seg- 
ment branch  from  common  basal  trunks  with  the  cereal  nerves,  and 
