NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS SNODGRASS        87 
differences  between  the  two  forms.  The  epiphallus  of  Gryllodes 
(G,  H,  I,  e)  lacks  the  median  recurved  process  of  Grylhis,  but  the 
two  lateral  epiphallic  lobes  (r,  s)  are  well  developed.  In  the  nymphal 
phallus  (B,  Phi)  the  large  dorsal  lobe  (C,  dl)  ends  in  three  terminal 
processes,  but  the  median  one  (v)  represents  the  ventral  rod  of  the 
adult  (I,  z')  that  guides  the  spermatophore  duct.  An  intermediate 
stage  is  shown  at  D,  which  was  taken  from  within  the  cuticle  of  C, 
and  probably  represents  the  beginning  of  the  imaginal  instar.  The 
median  process  is  here  a  slender  rod  (v)  at  the  base  of  which  is 
forming,  the  dorsal  cavity  (dc)  on  the  under  surface  of  the  dorsal 
lobe.  The  ventral  lobe  of  the  phallus  is  a  small,  inconspicuous  fold  in 
the  nymph  ("C,  vl)  beneath  the  base  of  the  dorsal  lobe,  but  in  the 
adult  it  becomes  much  enlarged,  deeply  emarginate,  and  is  ordinarily 
irregularly  folded  against  the  posterior  surface  of  the  phallus  (H,  vl). 
When  a  spermatophore  is  present  in  the  phallus,  however,  it  is  almost 
completely  embraced  by  the  expanded  lateral  halves  of  the  ventral 
lobe  (G,  vl),  which  enclose  a  large  oval  cavity  in  which  is  held  the 
body  of  the  spermatophore  (E). 
The  spermatophore  of  Gryllodes  sigillatus  is  similar  in  shape  to  that 
of  Gryllus,  but  structurally  quite  different  in  some  respects.  The 
sperm  capsule  is  a  small  spherical  ampulla  (E,  a)  attached  by  a 
sunken  neck  to  the  upper  surface  of  a  large  oval  supporting  body  (c). 
A  long,  slender,  recurved  duct  {dct)  extends  anteriorly  from  the 
capsule,  and  at  its  base  is  a  small  attachment  plate  {y).  The  single 
example  of  the  spermatophore  was  obtained  from  a  male  specimen  in 
alcohol.  Before  removal,  the  oval  body  of  the  spermatophore  was 
held  in  the  pocket  of  the  ventral  lobe  of  the  phallus  (G,  vl) ,  the  sperm 
capsule  projected  dorsally  before  the  mouth  of  the  dorsal  phallic 
cavity  {dc),  and  the  curved  duct  followed  the  median  groove  of  the 
latter  into  the  ventral  channel  of  the  guide  rod  {v).  The  dorsal  sac  of 
the  phallus  is  oval  and  compressed  (H,  J,  k)  ;  its  lateral  walls  are 
formed  of  a  thin,  transparent  membrane,  but  are  covered  by  a 
muscular  sheath  (not  shown  in  the  figures)  as  in  Gryllus.  At  the 
mouth  of  the  sac,  just  within  the  ventral  lip  (J,  g)  is  the  mold  (w) 
of  the  relatively  small  attachment  plate  of  the  spermatophore  (E,  y), 
and  from  the  mold  is  continued  the  grooved  channel  (H,  I,  J,  u)  to 
the  guide  rod  {l,v).  The  rod,  as  seen  in  lateral  view  (F),  is  abruptly 
curved  upward  at  its  base,  and  then  goes  posteriorly.  The  base  of 
the  rod  is  supported  by  a  large,  U-shaped  sclerite  (H,  T,  J,  t)  in  the 
dorsal  wall  of  the  dorsal  sac,  on  which  are  inserted  protractor  muscles 
from  the  sides  of  the  epiphallus  (H). 
