NO.    5      MALE  GENITALIA  OF  ORTHOPTRROID  INSECTS— SNODGRASS        25 
comparable  with  the  testis  of  Chilopoda  ;  but  since  the  usual  compound 
type  occurs  in  Timcnm,  it  seems  more  probable  that  the  common 
form  of  the  testis  in  the  Phasmatidae  has  been  produced  secondarily 
by  an  amalgamation  of  the  primitive  sperm  tubes. 
The  accessory  genital  glands. — Tubular  diverticula  of  the  ejacula- 
tory  duct,  most  of  which  are  probably  genital  accessory  glands,  are 
present  in  each  of  the  several  species  of  Phasmatidae  that  have  been 
studied.  In  Timema  californica  the  tubules  are  relatively  numerous 
and  of  different  sizes  (fig.  7  B,  AcGlds).  In  Leptyniella  attemiata  a 
pair  of  long  lateral  tubules  (A.  Vsm)  are  described  by  De  Sinety 
(1901)  as  vesiculae  seminales,  and  a  group  of  six  median  tubules 
(AcGlds)  as  accessory  glands.  A  compact  mass  of  tubules  is  present 
in  Diapheroiiiera  femorata  (C)  lying  against  the  ventral  wall  of  the 
eighth  abdominal  seginent.  The  individual  tubes  are  dit^cult  to  sepa- 
rate, but  careful  manipulation  reveals  six  of  them.  At  least  four  are 
thick,  orange-yellow  sacs  (AcGlds),  but  the  tubule  on  the  right  is 
always  longer  and  more  coiled  than  the  others,  and  has  a  pale  pink  color 
(in  alcoholic  specimens).  The  accessory  tubules  of  Caraiisins  morosus 
as  shown  by  Pehani  (1925)  are  similar  to  those  of  Diapheromera; 
two  lateral  tubules  of  the  group  are  much  larger  than  the  others,  and 
are  regarded  by  Pehani  as  seminal  vesicles.  In  a  specimen  of  Aniso- 
niorpha  bitprestoides  only  two  saclike  diverticula  were  found  (fig. 
8F)  arising  from  the  vasa  deferentia,  but  the  specimen  may  have 
been  immature.  A  phallic  gland  corresponding  with  that  present  in 
Mantidae  and  Blattidae  has  not  been  observed  in  the  Phasmatidae. 
The  external  genitalia  and  associated  structures. — -The  terminal 
parts  of  the  male  abdomen,  as  well  as  the  phallic  organs  themselves, 
are  highly  variable  in  different  species  of  the  Phasmatidae.  A  rela- 
tively generalized  structure  of  the  abdomen  is  found  in  Timcnia 
californica  (fig.  8  A,  B),  though  associated  here  with  a  very  special- 
ized development  of  the  cerci.  In  most  of  the  phasmatids  the  first 
abdominal  segment  is  as  completely  incorporated  into  the  metathorax 
as  it  is  in  the  higher  Hymenoptera,  but  in  Tinwnia  the  tergum  of  this 
segment  is  entirely  free  from  the  metatergum,  though  the  narrow 
sternum  is  united  with  the  metasternum.  The  genital  segments  of 
Timema  are  not  particularly  modified  (A,  B)  ;  the  ninth  sternum 
is  somewhat  prolonged  beneath  the  genital  organs,  but  there  is  no 
distinct  subgenital  plate  differentiated  from  it.  In  the  typical  phasma- 
tid  structure,  the  ninth  abdominal  sternum  is  completely  divided  into 
an  anterior  sternal  plate  (C,  J,  L,  IXS)  and  a  free  posterior  sub- 
genital  lobe  (IXSL).  The  sternal  plate  is  more  or  less  displaced 
anteriorly,  and  may  come  to  be  associated  with  the  eighth  segment 
