NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        59 
Amp),  and  gives  rise  to  the  accessory  glands  and  seminal  vesicles  of 
the  adult.  From  each  ampulla  in  a  late  nymphal  stage  there  may  be  a 
single  diverticulum,  but  the  great  mass  of  tubules  appears  only  in  the 
imaginal  stage.  The  ampullar  part  of  the  definitive  ejaculatory  duct 
may  be  bilobed  (fig.  25  G)  or  single;  in  Gryllotalpa  it  forms  a  large 
median  sac  (fig.  39  A)  from  v^hich  the  accessory  gland  tubules  arise. 
The  accessory  glands  always  consist  of  numerous  tubules  (figs.  20  A, 
27  C,  34  A,  39  A,  AcGlds),  which  differ  in  length,  and  may  be  dif- 
ferentiated into  several  groups  by  differences  in  size  and  probably 
in  the  nature  of  their  secretions.  In  Phaneroptera  furcata  (fig.  20  A) 
there  are  four  distinct,  paired  groups  of  tubules,  including  two  anterior 
groups  of  long  thick  tubes  (a),  lateral  clusters  of  shorter  and  more 
slender  tubules  {h),2i  dense  ventral  mass  of  still  smaller  ones  (c),  and 
finally  two  large,  compact  bodies  of  fine,  closely  interwoven  tubules 
{d)  projecting  laterally  and  posteriorly.  Bodies  of  tubules  similar  to 
the  last,  but  much  smaller,  are  present  also  in  Gryllotalpa  (fig.  39  A, 
d).  Sperm-containing  vesicles  comparable  with  those  of  Mantidae  and 
Blattidae  appear  to  be  absent  in  Tettigoniidae  and  Gryllidae,  but  in 
Gryllotalpa  two  large  tubular  diverticula  (fig.  39  A,  Vsm)  arise 
laterally  from  the  ejaculatory  duct  near  the  terminations  of  the  vasa 
deferentia,  which,  as  noted  by  Ito  (1924),  are  found  to  be  filled  with 
mature  spermatozoa,  their  heads  buried  in  the  vesicular  walls. 
The  posterior  ectodermal  part  of  the  ejaculatory  duct  is  wide  and 
usually  very  short.  Its  walls  are  continuous  posteriorly  with  those 
of  the  endophallus  (figs.  25  F,  32  E),  but  the  termination  of  the  duct 
is  always  marked  by  the  orifices  of  two  globular  vesicles  {ejv)  that 
open  into  it.  These  vesicles  of  the  ejaculatory  duct  are  characteristic 
features  of  the  Tettigonioidea  (figs.  20  A,  25  F,  C,  27  C,  32  E,  34  A, 
39  A).  They  have  been  termed  "prostate  glands",  and  should  have 
a  better  claim  to  this  name  than  the  phallic  glands  of  Blattidae  and 
Mantidae,  but  nothing  is  known  of  their  function.  According  to  Ito 
(1924)  the  lumen  of  each  vesicle  is  lined  by  a  thick  chitinous  intima 
and  contains  a  granular  mass  with  large  globules.  The  vesicles  usually 
have  a  pale  yellow  or  orange  color. 
The  accessory  glands,  the  ejaculatory  duct,  and  the  phallic  muscles 
are  innervated  by  branches  given  off  from  the  common  basal  trunks 
of  the  nerves  to  the  tenth  and  eleventh  segments  (figs.  34  D,  39  B). 
This  fact  suggests  that  the  ectodermal  phallus  and  ejaculatory  duct, 
as  well  as  the  mesodermal  ampullar  part  of  the  latter,  are  derived  from 
the  tenth  abdominal  somite. 
The  female  genital  organs  of  the  Tettigonioidea,  aside  from  the 
ovipositor,  are  simple  and  of  a  generalized  type  of  structure.    The 
