NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        85 
noted  presently.  The  ejaculatory  duct  (A,  Dcj)  is  a  wide  muscular 
tube  that  turns  downward  between  the  last  ganglion  of  the  ventral 
nerve  cord  and  the  dorsal  sac  of  the  phallus  (D,  Dej)  ;  it  then  goes 
posteriorly  and  enlarges  at  its  opening  into  the  endophallic  cavity 
(fig.  32  E).  A  pair  of  oval  lateral  vesicles  (ejv)  opens  into  the 
extreme  end  of  the  duct. 
The  spermatophore  of  Gryllus  assimilis  (fig.  32  F)  consists  of  a 
thick-walled,  ovate  or  pear-shaped  ampulla  (a),  of  an  elongate  attach- 
ment plate  {y)  connected  with  the  apex  of  the  ampulla  by  a  narrow 
neck,  and  of  a  slender  recurved  duct  {dct)  that  traverses  the  plate  and 
extends  far  beyond  it.  The  wall  of  the  ampulla,  as  observed  by  Spann 
(1934),  contains  three  distinct  layers.  The  innermost  layer  forms  a 
distinct  but  thin-walled  capsule  {d)  containing  the  spermatozoa;  the 
middle  layer  is  thick,  hard,  and  usually  dark  yellow  or  brown  in 
color;  the  outer  layer  is  a  thin,  transparent  external  covering,  which 
at  the  posterior  end  of  the  ampulla  forms  a  small  vesicular  papilla. 
The  middle  layer,  according  to  Spann,  takes  cytoplasmic  stains  and 
thus  shows  that  its  material  must  be  derived  from  the  larger  milky 
tubules  of  the  accessory  glands ;  the  outer  and  inner  layers,  on  the 
other  hand,  take  nuclear  stains,  and  hence  must  be  formed  from  the 
secretion  of  the  smaller  clear  tubules.  The  attachment  plate  of  the 
ampulla  is  pale  or  translucent,  and  its  substance,  Spann  says,  shows 
the  same  staining  reactions  as  the  outer  and  inner  coats  of  the  ampulla ; 
the  hard,  dark  middle  layer  of  the  ampulla  does  not  extend  into  the 
pliable  attachment  plate.  The  extremity  of  the  duct,  when  the  sperma- 
tophore is  taken  from  the  male,  Spann  claims,  is  normally  closed,  but 
if  the  tip  is  broken  off  the  spermatozoa  flow  out  from  it;  the  inner 
capsule  of  the  ampulla  is  then  seen  to  collapse  within  the  more  rigid 
outer  walls  as  air  diffuses  through  the  latter  to  occupy  the  space  around 
the  shrinking  capsule.  The  liberation  of  the  sperm  during  copulation, 
Spann  suggests,  is  probably  accomplished  by  a  dissolving  of  the  end 
of  the  duct  in  the  spermathecal  passage.  The  spermatophore  is  then 
emptied  of  spermatozoa  in  from  45  minutes  to  an  hour.  According  to 
Baumgartner  (1911),  however,  the  sperm  automatically  flows  out  of 
the  tip  of  the  duct  when  the  spermatophore  is  placed  in  normal  salt 
solution,  and  the  capsule  may  be  emptied  in  15  minutes,  but  whether 
the  tip  was  presumably  perfect  or  not  Baumgartner  does  not  say. 
The  mating  habits  of  Gryllus  and  Liogryllus,  the  structure  of 
the  male  genital  organs  and  the  spermatophore,  ha\'e  been  described 
by  Lespes  (1855,  1855a),  Baumgartner  (1911),  Gerhardt  (1913), 
and  Regan  (1924).  At  the  time  of  mating,  the  male  takes  a  position 
below  the  female.    Copulation  is  said  to  be  effected  by  the  thrusting 
