﻿OCCURRING 
  ON 
  RATS 
  IN 
  INDIA. 
  85 
  

  

  astia. 
  The 
  outer 
  flap 
  of 
  the 
  organs 
  of 
  copulation 
  is 
  studded 
  with 
  very 
  stout 
  bristles, 
  

   the 
  longest 
  of 
  which 
  is 
  curved 
  like 
  a 
  boomerang. 
  

  

  2. 
  Xenopsylla 
  cheopis, 
  Koths. 
  The 
  antepygidial 
  bristle 
  is 
  situated 
  on 
  a 
  

   short 
  pedestal, 
  which 
  is 
  placed 
  at 
  some 
  distance 
  from 
  the 
  apical 
  edge 
  of 
  the 
  

   seventh 
  segment. 
  The 
  outer 
  flap 
  of 
  the 
  copulatory 
  organs 
  is 
  sole-shaped, 
  its 
  upper 
  

   edge 
  being 
  more 
  curved 
  than 
  the 
  lower 
  edge. 
  This 
  flap 
  bears 
  nine 
  or 
  ten 
  bristles 
  on 
  

   the 
  outer 
  surface, 
  these 
  bristles 
  being 
  very 
  much 
  thinner 
  than 
  in 
  brasiliensis 
  and 
  

   drawn 
  out 
  into 
  a 
  long 
  thin 
  point. 
  The 
  ninth 
  sternite, 
  which 
  usually 
  projects 
  but 
  

   slightly 
  from 
  the 
  interior 
  of 
  the 
  eighth 
  segment, 
  is 
  widened 
  towards 
  the 
  apex, 
  having 
  

   more 
  or 
  less 
  the 
  shape 
  of 
  a 
  club 
  of 
  which 
  the 
  upper 
  side 
  is 
  somewhat 
  flattened. 
  The 
  

   upper 
  margin 
  of 
  this 
  club 
  is 
  as 
  distinct 
  as 
  the 
  ventral 
  margin 
  when 
  viewed 
  by 
  trans- 
  

   mitted 
  light 
  under 
  the 
  microscope. 
  

  

  3. 
  Xenopsylla 
  astia, 
  Koths. 
  The 
  antepygidial 
  bristle 
  is 
  similar 
  to 
  that 
  

   of 
  X. 
  cheopis. 
  This 
  species, 
  however, 
  in 
  the 
  male, 
  is 
  easily 
  differentiated 
  from 
  

   the 
  other 
  two 
  species 
  by 
  the 
  shape 
  of 
  the 
  ninth 
  sternite. 
  This 
  sternite, 
  instead 
  of 
  

   being 
  club-shaped, 
  has 
  the 
  appearance 
  of 
  a 
  ribbon 
  viewed 
  from 
  a 
  point 
  on 
  its 
  edge, 
  

   which 
  is 
  due 
  to 
  the 
  ventral 
  margin 
  being 
  strongly 
  chitinised, 
  whereas 
  the 
  sides 
  and 
  

   upper 
  margin 
  are 
  very 
  thin 
  and 
  transparent. 
  The 
  outer 
  flap 
  of 
  the 
  organs 
  of 
  copu- 
  

   lation 
  is 
  narrower 
  than 
  in 
  X. 
  cheopis 
  and 
  bears 
  fewer 
  bristles. 
  The 
  species 
  is 
  replaced 
  

   in 
  Africa 
  by 
  X. 
  nubicus, 
  which 
  differs 
  in 
  minor 
  details 
  only. 
  

  

  II. 
  Females. 
  

  

  The 
  three 
  species 
  are 
  distinguished 
  at 
  a 
  glance 
  by 
  the 
  shape 
  of 
  the 
  receptaculum 
  

   seminis. 
  This 
  organ 
  is 
  divided 
  by 
  a 
  deep 
  constriction 
  into 
  a 
  short 
  rounded 
  portion, 
  

   the 
  " 
  head," 
  and 
  a 
  more 
  or 
  less 
  sausage-shaped 
  portion, 
  the 
  " 
  tail." 
  

  

  1. 
  Xenopsylla 
  brasiliensis. 
  The 
  "head" 
  of 
  the 
  receptaculum 
  seminis 
  is 
  

   very 
  much 
  wider 
  than 
  the 
  " 
  tail." 
  The 
  abdominal 
  segments 
  III 
  to 
  VI 
  bear 
  

   ventrally 
  on 
  each 
  side 
  a 
  row 
  of 
  4 
  bristles, 
  and 
  the 
  eighth 
  segment 
  has 
  on 
  the 
  outer 
  

   surface 
  less 
  than 
  20 
  bristles. 
  

  

  2. 
  Xenopsylla 
  Cheopis. 
  The 
  " 
  tail 
  " 
  of 
  the 
  receptaculum 
  is 
  much 
  longer 
  than 
  

   in 
  X. 
  brasiliensis 
  and, 
  near 
  the 
  constriction, 
  distinctly 
  wider 
  than 
  the 
  " 
  head." 
  

   The 
  abdominal 
  segments 
  III-VI 
  bear 
  ventrally 
  on 
  each 
  side 
  a 
  row 
  of 
  three 
  or 
  four, 
  

   rarely 
  five, 
  bristles, 
  and 
  the 
  eighth 
  segment 
  has 
  less 
  than 
  30 
  bristles, 
  usually 
  20 
  to 
  25. 
  

  

  3. 
  Xenopsylla 
  astia. 
  The 
  " 
  tail 
  " 
  of 
  the 
  receptaculum 
  is 
  so 
  strongly 
  widened 
  

   near 
  the 
  constriction 
  that 
  it 
  is 
  here 
  very 
  much 
  wider 
  than 
  the 
  " 
  head 
  " 
  ; 
  

   the 
  " 
  tail," 
  moreover, 
  is 
  shorter 
  than 
  in 
  X. 
  cheopis. 
  The 
  abdominal 
  segments 
  

   III-VI 
  bear 
  ventrally 
  a 
  row 
  of 
  seven 
  or 
  eight 
  bristles 
  on 
  each 
  side, 
  and 
  segment 
  VIII 
  

   has 
  more 
  than 
  30 
  bristles 
  on 
  the 
  outer 
  surface. 
  

  

  