82  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
Walker  discards,  seems  to  the  writer  the  only  logical  interpretation 
of  the  gryllid  structure,  since  the  latter  is  so  clearly  but  an  adaptation 
of  the  Structure  of  the  phallus  in  Ccuthophihis  (fig.  30  D),  which  in 
turn  is  derived  from  the  more  primitive  tettigoniid  structure  (cf .  figs. 
22  D  and  F  with  fig,  32  E) . 
The  endophallic  cavity,  together  with  the  space  between  the  lateral 
flaps  of  the  ventral  phallic  lobe  and  the  floor  of  the  genital  chamber, 
forms  the  mold  of  the  large,  oval  ampulla  of  the  spermatophore  (fig. 
32  G,  a) .  When  the  fully  formed  spermatophore  is  still  in  place 
within  the  phallus,  the  ampulla  is  almost  entirely  enclosed  by  the 
flaps  of  the  ventral  lobe,  and  the  mouth  of  the  ejaculatory  duct  (Dej) 
is  pressed  close  against  the  anterior  part  of  its  ventral  surface;  the 
narrow  neck  connecting  the  ampulla  with  the  attachment  plate  (y) 
curves  over  the  lower  lip  (g)  of  the  dorsal  sac  and  expands  upon  the 
ventral  plate  of  the  latter. 
The  development  of  the  phallus  of  Gryllus  can  be  followed  in  the 
nymph,  but  the  phallic  development  of  each  instar  begins  in  the 
preceding  instar  long  before  there  is  any  evidence  of  ecdysis  on  other 
parts  of  the  body.  On  removal  of  the  cuticula  from  the  genital  region 
of  any  instar  there  is  hence  usually  found  beneath  it  the  phallus  of 
the  next  instar,  which  already  has  taken  on  quite  a  different  form. 
In  a  half -grown  male  nymph  (fig.  33  A)  the  phallic  rudiments  are 
slightly  embossed  on  an  oval  area  of  the  genital  chamber  wall  (B)  ; 
they  include  a  pair  of  oval  dorsal  swellings  {dl),  a  pair  of  similar 
ventral  swellings  {vl),  and  a  somewhat  depressed  central  disk  {dc) 
with  a  faint  median  groove.  At  the  lower  end  of  the  last  is  the  gono- 
pore  rudiment  (Gpr).  By  removing  the  cuticula  there  will  probably 
be  exposed  the  phallus  of  the  next  instar  developing  beneath  it  (C). 
At  this  stage  the  dorsal  elevations  are  united  in  a  large  dorsal  lobe 
(dl)  with  a  prominent  median  projection  (q),  which  will  become  the 
median  lobe  of  the  epiphallus  of  the  adult  (fig.  32  C,  q).  The  ventral 
swellings  of  the  preceding  instar  (fig.  33  B,  vl)  are  likewise  united 
to  form  an  emarginate  ventral  lobe  (C,  vl).  The  central  area  is  still 
more  depressed,  but  shows  no  distinction  between  a  dorsal  cavity  and 
a  ventral  cavity.  At  a  later  stage  (D,  E)  the  dorsal  lobe  is  clearly 
taking  on  the  form  of  the  epiphallus  of  the  adult,  and  a  thick,  tapering 
grooved  process  (v)  projects  from  the  dorsal  wall  of  the  median 
depression  below  it.  Again,  by  removal  of  the  cuticula,  there  is 
exposed  the  phallus  of  the  succeeding  instar  (F),  which  is  perhaps 
the  beginning  of  the  imago,  for  the  organ  now  has  distinctly  adult 
characters.  The  epiphallus  has  become  differentiated  into  three  apical 
lobes,  and  the  ventral  process  (v)  has  taken  the  form  of  a  slender  rod 
