NO.    5      MALE  GENITALIA  OF  ORTHOI'TEROID  INSECTS SNODGRASS         Si 
within  which  may  be  seen  the  short  membranous  penis  (A,  E,  Pen), 
but  the  phallomeres  arc  usually  entirely  concealed  in  their  lateral 
pouches  (E,  3;,  c).  The  much-reduced  right  phallomere  (D,  E,  rPhm) 
consists  of  two  small  sujjerposed  lamellae  at  the  bottom  of  the  right 
pouch  (y),  with  a  short  apodeme  (/>)  projecting  from  the  wall  of 
the  latter.  The  left  phallomere  is  a  long,  thick,  strongly  sclerotized 
rod  with  a  hooked  extremity  (E,  IPhni),  contained  in  a  corres- 
pondingly deep  pouch  {s).  By  the  complete  eversion  of  the  pouch, 
however,  the  left  phallomere  can  be  protracted  far  beyond  the  end  of 
IPhm 
Fig.  18. — Blattoidea :  abdomen  and  external  male  genitalia  of  Ecfobius  lap- 
ponicus  (Linnaeus). 
A,  end  of  abdomen,  showing  penis  (Pen)  in  base  of  genital  chamber,  dorsal 
view.  B,  same,  ventral  view.  C,  same,  ventral  view,  with  left  phallomere  pro- 
jected on  everted  pouch  (^).  D,  right  phallomere  in  right  phallic  pouch  (y). 
E,  general  view  of  retracted  genitalia,  somewhat  diagrammatic,  including  ninth 
sternum  and  its  apodemal  arms  (IXSAps),  dorsal  view.  F,  left  phallomere 
projected,  penis  (Pen),  and  endophallic  apodeme  (Ape). 
For  letter  explanation,  see  fig.  16. 
the  abdomen  (C,  F).  The  penis  is  a  short  membranous  lobe  (E,  F, 
Pen)  with  a  small  endophallic  cavity  opening  at  its  extremity.  The 
penis  is  unarmed,  but  from  the  endophallic  wall  there  arises  a  long 
apodeme  (Ape),  which  extends  forward  and  to  the  left  into  the  fourth 
abdominal  segment. 
The  type  of  phallic  structure  here  shown  in  Ectobia  and  Blattella, 
representing  the  Ectobiinae  and  Pseudomopinae,  occurs  in  many 
other  forms,  certainly  including,  as  is  evident  from  the  descriptions  and 
figures  of  Chopard  (1920),  the  Nyctiborinae,  Epilamprinae,  Pan- 
chlorinae,  and  Perisphaerinae. 
