﻿The 
  Anatomy 
  of 
  the 
  Female 
  Genital 
  Tract 
  of 
  the 
  Pnpipara 
  etc. 
  

  

  23 
  

  

  front 
  of 
  which 
  they 
  break 
  into 
  a 
  nnmber 
  of 
  branches 
  which 
  pass 
  

   around 
  it 
  on 
  all 
  sides 
  (PI. 
  II, 
  Fig. 
  3 
  tr). 
  

  

  The 
  uterus 
  is 
  composecl 
  of 
  two 
  distinctly 
  different 
  divisions, 
  the 
  

   posterior 
  half, 
  the 
  walls 
  of 
  which 
  are 
  in 
  all 
  respects 
  like 
  those 
  of 
  

   the 
  vagina, 
  and 
  the 
  anterior 
  half, 
  whose 
  walls 
  are 
  of 
  quite 
  a 
  differ- 
  

   ent 
  character 
  in 
  that 
  they 
  have 
  the 
  thin, 
  delicate 
  cuticula 
  already 
  

   mentioned, 
  and 
  are 
  besides 
  thrown 
  into 
  thick 
  folds 
  so 
  that 
  the 
  lumen 
  

   is 
  Yery 
  irregulär 
  in 
  shape 
  and 
  in 
  the 
  erapty 
  uterus 
  is 
  often 
  entirely 
  

   closed. 
  It 
  is 
  into 
  this 
  anterior 
  portion 
  of 
  the 
  uterus 
  that 
  the 
  egg 
  

   arrives 
  when 
  it 
  has 
  been 
  extruded 
  from 
  the 
  ovary 
  and 
  where 
  it 
  

   remains 
  while 
  the 
  enibryonic 
  deyelopment 
  proceeds. 
  The 
  young 
  

   larya 
  on 
  hatching 
  also 
  occupies 
  the 
  same 
  place 
  but 
  gradually 
  grows 
  

   towards 
  the 
  posterior 
  end 
  until 
  it 
  fills 
  the 
  entire 
  uterus. 
  

  

  The 
  milk-glands. 
  

  

  At 
  the 
  anterior 
  end 
  of 
  the 
  uterus 
  its 
  dorsal 
  surface 
  is 
  pierced 
  

   by 
  an 
  opening 
  throngh 
  which 
  the 
  two 
  pairs 
  of 
  milk-glands 
  com- 
  

   municate 
  with 
  it 
  (PL 
  II, 
  Fig. 
  3 
  and 
  4 
  o 
  p.m. 
  gl). 
  Leuckaet 
  (10) 
  states 
  

   wrongly 
  that 
  there 
  are 
  two 
  openings, 
  one 
  for 
  each 
  pair 
  of 
  glands 
  

   and 
  one 
  in 
  front 
  of 
  the 
  other, 
  and 
  that 
  they 
  are 
  in 
  the 
  dorsal 
  wall 
  

   of 
  the 
  median 
  oviduct. 
  The 
  forward 
  pair 
  is 
  composecl 
  of 
  two 
  thick, 
  

   short 
  tubes 
  ayeraging 
  0,5 
  mm 
  each 
  in 
  length 
  and 
  0,06 
  mm 
  in 
  diameter, 
  

   whose 
  proximal 
  ends 
  are 
  fused 
  to 
  form 
  a 
  Single 
  tube 
  (PI. 
  III, 
  Fig. 
  8 
  

   a.m.gl, 
  PI. 
  II, 
  Fig. 
  2 
  a.m.gl). 
  The 
  hinder 
  pair 
  is 
  composed 
  of 
  two 
  

   large, 
  extensiyely 
  branched, 
  tubulär 
  structures 
  which 
  also 
  fuse 
  at 
  

   their 
  extreme 
  proximal 
  ends 
  to 
  form 
  a 
  Single 
  yessel 
  [p.m. 
  gl). 
  The 
  

   median, 
  proximal 
  ends 
  of 
  the 
  two 
  gland-pairs 
  meet 
  at 
  the 
  opening 
  

   in 
  the 
  wall 
  of 
  the 
  uterus 
  and 
  are 
  there 
  bound 
  together 
  by 
  a 
  sheath 
  

   of 
  muscle-fibres 
  (Fig. 
  9). 
  The 
  function 
  of 
  these 
  two 
  pairs 
  of 
  glands 
  

   is 
  to 
  furnish 
  the 
  milk-like 
  fluid 
  which 
  serves 
  as 
  food 
  for 
  the 
  growing 
  

   larya. 
  The 
  forward, 
  club-shaped 
  pair 
  has 
  probably 
  largely 
  lost 
  this 
  

   function 
  and 
  become 
  more 
  or 
  less 
  rudimentary, 
  and 
  as 
  is 
  usually 
  

   the 
  case 
  with 
  rudimentary 
  organs 
  they 
  show 
  a 
  considerable 
  amount 
  

   of 
  individual 
  Variation. 
  They 
  are 
  often 
  so 
  small 
  as 
  to 
  be 
  found 
  with 
  

   difficulty 
  or 
  may 
  reach 
  the 
  considerable 
  deyelopment 
  represented 
  in 
  Fig. 
  8. 
  

   They 
  may 
  even 
  be 
  found 
  much 
  larger 
  than 
  these 
  and 
  Leuckaet 
  (10) 
  

   has 
  obseryed 
  cases 
  in 
  which 
  the 
  distal 
  ends 
  of 
  these 
  glands 
  branched 
  

   dichotomically 
  like 
  the 
  posterior 
  pair. 
  In 
  Hippobosca, 
  according 
  to 
  

   Düfour 
  (4), 
  the 
  anterior 
  glands 
  are 
  long 
  branched 
  structures. 
  

  

  The 
  nutriment 
  of 
  the 
  larva 
  in 
  Melophagus 
  is 
  undoubtedly 
  furn- 
  

  

  