NO.    5      MALF.  GENITALIA  OF  OKTHOPTEKOID  INSECTS— SNODC.RASS         35 
on  each  other  ;  muscles  14  and  /■>,  together  with  //,  ]:)rohahly  effect  a 
change  in  the  shape  of  the  left  phallonierc  that  gives  a  movement 
to  the  distal  processes. 
1(5.  An  ohlique  muscle  (fig.  10  D)  from  the  mesal  sclerite  of  the 
left  phallomere  to  the  ventral  plate  of  the  ventral  phallomere. 
//.  Intrinsic  muscle  of  the  ventral  phallomere  (iig.  10  F). — A 
wide  fan  of  fibers  arising  on  the  ventral  plate  of  the  ventral  phal- 
lomere and  converging  to  the  base  of  the  distal  arm  (/). 
Mating  habits  and  spermatophores. — The  mating  habits  of  the 
mantids  is  a  subject  on  vv^hich  vi^riters  seldom  fail  to  become  emotional ; 
it  furnishes  the  high  point  in  the  curve  of  literary  entomology.  The 
female  mantis  is  frequently  observed  to  attack  and  more  or  less  com- 
pletely devour  the  male  before  or  during  copulation,  an  act  which, 
of  course,  can  be  made  to  seem  highly  sensational.  A  recent  analysis 
of  the  sexual  behavior  of  the  mantis  by  Roeder  (1935),  however, 
puts  the  matter  on  a  physiological  basis.  The  principal  sense  organs 
of  the  mantids  are  the  eyes,  but  the  only  visual  perception  is  motion. 
Any  moving  object,  therefore,  is  to  the  mantid  an  article  of  food 
and  calls  forth  the  attack  response.  The  male  mantis,  preliminary  to 
copulation,  leaps  upon  the  back  of  the  female  and  normally  grasps 
her  by  the  mesothorax  and  the  edges  of  the  wings.  If  the  male  attains 
this  hold  at  the  first  attempt,  according  to  Roeder,  the  female  is  com- 
pletely negative,  giving  no  sign  that  she  recognizes  the  presence  of  the 
male,  and  making  no  attack  on  him.  In  any  other  position,  however, 
the  male  mantid  is  to  the  female  only  another  insect.  Thus,  Roeder 
says,  "  if  the  male  approaches  the  female  from  the  side,  landing  on 
her  back  at  right  angles,  or  instead  of  clasping  the  mesothorax  with 
his  raptorial  arms,  grips  her  by  the  head  or  only  by  the  tips  of  the 
wings,  the  female  then  immediately  wheels  and  grabs  him."  The 
numerous  records  of  cannibalism  on  the  part  of  the  female  mantis, 
Roeder  suggests,  are  largely  the  result  of  disturbance  of  the  insects 
by  the  observer,  or  of  the  limited  space  in  cages  in  which  the  insects 
are  confined. 
If,  however,  the  female  for  any  reason  does  attack  and  partially  eat 
the  male  during  copulation,  the  sexual  act  is  not  prevented  or  arrested, 
since,  as  Roeder  demonstrates,  the  copulatory  apparatus  is  controlled 
entirely  by  the  last  nerve  ganglion  of  the  abdomen.  Furthermore,  by 
decapitation  the  copulating  movements  are  greatly  increased  because 
the  activating  mechanism  is  now  released  from  the  inhibitory  stimulus 
that  normally  arises  in  the  suboesophageal  ganglion  of  the  head.  De- 
capitated insects,  under  any  circumstances,  Roeder  shows,  make  con- 
