NO.    5      MAIM  GENITALIA  OF  OUTIIOl'TEROID  INSECTS SNODGRASS         39 
(fig.  II  C)  and  /'rriplaiicfa  ( IV^.  15  D,  Ji)  tlic  glands  arc  dilTcrcn- 
tiated  into  a  median  ^ronp  of  short  tnlniles  (a)  and  lateral  groups  of 
longer  tubules  (b),  the  "  utriculi  breviores  "  and  "  utriculi  niajores  " 
of  Miall  and  Denny  (1886).  In  Blaiiella  gcnuanica  (fig.  16  A) 
and  in  Cryptoccrcns  pnuctiilatiis  (Cleveland,  1934)  a  group  of  tubules 
corresponding  with  the  larger  tubules  of  Blatta  and  Periplaneta  forms 
the  usual  compact  cluster  on  the  end  of  the  ejaculatory  duct,  but 
projecting  forward  far  beyond  the  latter  is  a  group  of  long,  thick, 
chalky  white  tubes.  In  Blattella  those  long  glands  are  usually  six  in 
number  (fig.  16  A,  C,  d)  though  some  are  united  at  their  bases,  and 
they  arise  from  the  left  branch  of  the  bifurcate  anterior  end  of  the 
ejaculatory  duct  (C).  These  tubes  lie  in  the  ventral  part  of  the 
abdomen,  where  in  freshly  killed  specimens  they  show  through  the 
integument  as  a  conspicuous  white  mass  extending  from  the  posterior 
part  of  the  seventh  segment  to  the  anterior  edge  of  the  fourth. 
The  secretion  of  the  male  accessory  glands  of  Blattidae  has  been 
but  little  studied,  and  the  function  of  the  secretion  cannot  be  definitely 
stated  until  the  method  of  insemination  of  the  female  is  better  known. 
Ito  (1924)  says  the  male  accessory  glands  of  Blatta  orientalis  form 
a  spermatic  fluid,  which  stimulates  the  activity  of  the  spermatozoa. 
The  corresponding  glands  of  other  Orthoptera  furnish  the  material 
of  the  spermatophores.  A  spermatophore  has  been  observed  among 
the  roaches  only  in  Blatta  orientalis  (fig.  11  H),  described  by  Zabin- 
ski  (1933  a)  as  consisting  of  several  layers,  the  first  of  which  he 
believes  must  be  formed  by  the  small  median  tubules  of  the  accessory 
glands,  and  the  other  outer  coats  by  the  larger  tubules.  The  two 
sets  of  gland  tubules  of  Blatta  differ  in  appearance  in  a  manner  sug- 
gestive of  a  functional  difiference.  The  larger  peripheral  tubules 
(fig.  II  J)  are  turgid  and  opaquely  white  when  freshly  dissected 
in  water,  Ijut  they  quickly  become  clear  in  glycerine.  Most  of  the 
smaller  tubules  contain  each  a  dark  inner  tube  (D,  e)  compressed 
into  irregular  folds,  which  under  pressure  slides  out  of  its  sheath 
(E,  /)  and  may  expand  to  a  length  double  or  more  that  of  the  outer 
gland  wall.  When  crushed,  some  of  the  inner  tubes  are  seen  to  con- 
tain innumerable  dark  granules.  The  writer  at  first  suspected  that 
these  inner  tubes  of  the  smaller  glands  might  have  some  relation  to 
the  spermatophores,  but  no  evidence  of  their  nature  or  function  was 
obtained.  Miall  and  Denny  (1886)  say  that  in  the  adult  of  Blatta 
orientalis  "  the  utriculi  are  usually  distended  with  spermatozoa,  and 
are  of  a  brilliant  opaque  white."  The  writer  has  failed  to  discover 
spermatozoa  in  any  of  the  glandular  tubules  of  Blatta,  Periplaneta, 
or  Blattella. 
