NO.    5      MALE  GENITALIA  OF  ORTHOPTEROID  INSECTS — SNODGRASS        83 
arising  from  a  flaring  base.  Proximal  to  the  latter  is  the  mouth  of 
a  deep  dorsal  cavity  (dc),  the  ventral  lip  of  which  (g)  appears  as  a 
septum  between  the  upper  cavity  and  a  lower  endophallic  cavity  above 
the  ventral  lobe  (vl).  The  ventral  lobe  itself  is  much  enlarged,  deeply 
cleft,  and  has  several  marginal  lobules.  Whether  a  stage  intervenes 
between  this  one  (F)  and  the  fully  mature  adult  (fig.  32  C)  was  not 
determined,  but  the  specimen  appeared  to  be  a  pre-imaginal  nymph. 
The  internal  reproductive  organs  of  the  male  cricket  (fig.  34  A) 
are  characterized  by  the  large  size  of  the  testes,  the  relatively  uniform 
dc      e      q  dl 
VPapt^ 
B     ^P 
Fig.  33. — Tettigonioidea-Gryllidae : 
Gyyllus  assimilis  Fabricius. 
nymphal  development  of  the  phallus  of 
A,  half-grown  nymph  in  premoulting  condition,  end  of  abdomen,  ventral  viewr. 
B,  same,  phallic  rudiments  in  genital  chamber  wall  beneath  bases  of  paraprocts, 
posterior  view.  C,  phallus  of  succeeding  instar  exposed  by  removal  of  cuticula 
from  B,  posterior  view.  D,  phallus  of  later  nymphal  instar,  posterior  view. 
E,  same,  ventral  view.  F,  phallus  of  succeeding  instar  (perhaps  immature 
adult)  exposed  by  removal  of  cuticula  from  E,  ventral  view. 
For  letter  explanation,  see  fig.  30. 
size  of  the  accessory  gland  tubules,  and  the  absence  of  sperm  vesicles. 
The  mature  testes  (Tes)  lie  against  the  lateral  and  dorsal  walls  of 
the  second,  third,  and  fourth  abdominal  segments,  where  they  overlap 
the  rear  end  of  the  crop,  and  almost  meet  along  the  midline  of  the 
back.  Each  testis  consists  of  a  large  number  of  slender  sperm  tubules 
(B),  approximately  280,  according  to  Spann  (1934),  which  overlie 
one  another  in  concentric  layers  diverging  posteriorly  from  the 
anterior  end  of  the  testis,  and  are  enveloped  in  a  delicate  peritoneal 
sheath.  The  tubules  discharge  through  narrow  efferent  ducts  into  the 
enlarged  intra-testicular  part  of  the  vas  deferens.    Beyond  the  testis 
