NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        9I 
tigoniidae.  In  a  young  nymph  of  Ncmobius  fasciatus,  in  which  the 
hind  wings  do  not  yet  project  from  the  margin  of  the  metatergum, 
and  the  subgenital  sternum  is  not  enlarged  (fig.  37  A),  the  phallus  is 
a  small,  simple  lobe  in  the  genital  pocket  above  the  ninth  sternum  (B). 
With  its  base  is  connected  a  pair  of  slender  ventral  extensions  {xt) 
of  the  tenth  tergum  (C),  suggestive  that  the  phallus  is  primarily  a 
derivative  of  the  tenth  segment  and  not  of  the  ninth.    The  phallic 
Fig.  Z7. — Tettigonioidea-Gryllidae :  nymphal  development  of  the  phallus  of 
Nemobhis  fasciatiis  (Degeer). 
A,  young  wingless  nymph,  end  of  abdomen,  ventral  view.  B,  same,  phallus, 
ventral  view.  C,  older  nymph  with  hind  wings  reaching  to  end  of  first  abdominal 
tergum,  end  of  abdomen  with  subgenital  plate  (IXS)  partly  removed  to  expose 
phallus  (Phi),  postero-ventral  view.  D,  same,  phallus,  ventral  view.  E,  phallus 
of  nymph  with  hind  wings  reaching  almost  to  fifth  abdominal  tergum,  ventral 
view.  F,  phallus  of  succeeding  instar  (perhaps  immature  adult)  exposed  by 
removal  of  cuticula  from  E. 
For  letter  explanation,  see  fig.  30. 
rudiment  consists  of  a  thick  dorsal  lobe  (B,  dl),  and  a  short,  wide 
ventral  lobe  (vl).  The  distal  surface  of  the  dorsal  lobe  presents  a 
shallow  depression  (dc),  which  is  the  beginning  of  the  dorsal  cavity, 
the  exposed  position  of  which  suggests  its  identity  with  the  dorsal 
phallic  cavity  of  Tettigoniidae.  At  a  somewhat  later  stage,  when  the 
hind  wings  extend  to  the  end  of  the  first  abdominal  tergum,  the  phallus 
has  changed  but  little  in  structure  (C,  D)  ;  but  when  the  wings  reach 
to  the  fifth  abdominal  segment,  the  phallus  (E)  begins  to  show  some 
of  the  adult  modifications.   If  the  specimen  is  in  a  premoulting  condi- 
