58  SMITHSONIAN    MISCELLANEOUS    COLLECTIONS  VOL.    96 
formation  in  Blattella  germanica.  Free  spermatozoa,  he  says,  are 
present  in  the  seminal  receptacles  of  females  examined  the  morning 
following  mating  that  took  place  during  the  night,  but  no  trace  of 
spermatophore  capsules  is  to  be  seen. 
IX.   TETTIGONIOIDEA 
The  external  genital  apparatus  of  the  adult  male  of  tettigoniid, 
gryllid,  and  acridid  Orthoptera  diiTers  from  that  of  the  Blattidae  and 
Mantidae  in  that  it  consists  of  a  single  phallic  structure  which  encloses 
the  opening  of  the  ejaculatory  duct.  The  organ  is  developed  in  the 
nymph,  however,  from  primitive  genital  lobes  (phallomeres)  that 
grow  out  from  the  genital  integument  around  the  gonopore. 
The  mature  phallus  of  the  Tettigonioidea  has  a  distinctive  type  of 
structure,  which  fact  can  leave  no  doubt  of  the  close  relationship  of 
the  several  families  included  in  this  group  (Tettigoniidae,  Gryllidae, 
and  related  forms  variously  classified  by  taxonomists).  Unquestion- 
ably a  wider  comparative  study  of  the  organ  would  give  valuable 
evidence  on  the  natural  classification  of  the  families.  Since  the 
structure  of  the  phallus  is  adapted  to  the  formation"  of  a  spermato- 
phore, the  nature  of  the  spermatophore  itself  should  be  an  index  to 
relationships.  Judging  from  what  is  known  concerning  the  spermato- 
phores  of  members  of  several  families,  it  seems  probable  that  the 
families  will  be  found  to  fall  into  two  series,  according  to  whether  the 
spermatophore  contains  a  single  sperm  capsule,  or  two  sperm  capsules. 
The  internal  reproductive  organs  of  male  Tettigonioidea  exemplify 
the  typical  orthopteran  structure  of  these  parts  in  a  highly  developed 
condition  (figs.  20  A,  27  C,  34  A,  39  A).  The  testes  {Tes)  are 
compact  bodies,  each  composed  of  a  large  number  of  sperm  tubes 
(fig.  27  D,  ST)  surrounded  by  a  peritoneal  sheath  (PSh).  The  vas 
deferens  (Vd)  penetrates  into  the  testis  and  the  sperm  tubes  converge 
upon  its  anterior  end,  which  may  be  much  enlarged.  Beyond  the 
testis  each  vas  deferens  is  thrown  into  numerous  loops,  forming  an 
epididymis-like  body  (figs.  20  A,  27  C,  34  C,  39,  Epdin)  that  attains 
a  particularly  large  size  in  the  Gryllotalpidae  (fig.  39).  Posteriorly 
the  vasa  deferentia  turn  mesad  and  ventrally,  going  beneath  the  large 
cereal  nerves  of  the  eleventh  abdominal  segment  (figs.  20  A,  34  A, 
39  B,  XINv),  and  then  forward  to  enter  the  anterior  part  of  the 
ductus  ejaculatorius. 
The  ejaculatory  duct  (if  the  name  is  given  to  the  entire  median 
genital  exit  passage  of  the  adult)  is  clearly  composed  of  both  ecto- 
dermal and  mesodermal  parts.  The  mesodermal  section  is  formed  of 
the  united  embryonic  ampullae  of  the  vasa  deferentia  (figs.  21  E,  31  E, 
