﻿Studies 
  on 
  Synapsis. 
  

  

  289 
  

  

  (3) 
  Agamic 
  Female, 
  Production. 
  — 
  With 
  regard 
  to 
  the 
  production 
  of 
  females 
  

   from 
  parthenogenetic 
  eggs, 
  the 
  case 
  of 
  Bhodites 
  and 
  Cynips 
  has 
  been 
  

   considered, 
  and 
  Henking's 
  account 
  of 
  the 
  former 
  has 
  been 
  vindicated. 
  

   It 
  appears 
  that 
  there 
  is 
  a 
  reduction 
  of 
  the 
  number 
  of 
  chromosomes 
  in 
  the 
  

   young 
  oocyte 
  of 
  both 
  these 
  forms, 
  and 
  it 
  may 
  be 
  assitmed 
  that 
  Henking 
  rightly 
  

   described 
  the 
  double- 
  equational 
  formation 
  of 
  polar 
  bodies 
  with 
  subsequent 
  

   disjunction 
  of 
  univalent 
  halves 
  in 
  the 
  female 
  pronucleus 
  of 
  the 
  former. 
  This 
  

   is 
  not 
  in 
  conflict 
  with 
  the 
  case 
  of 
  Neuroterus, 
  where, 
  although 
  no 
  polar 
  

   bodies 
  are 
  formed 
  in 
  the 
  female-producing 
  ova 
  of 
  the 
  agamic 
  generation, 
  all 
  

   the 
  oocytes 
  appear 
  to 
  show 
  the 
  reduced 
  number 
  of 
  chromosomes 
  at 
  the 
  

   corresponding 
  stage. 
  

  

  (4) 
  A 
  study 
  of 
  the 
  early 
  oogenesis 
  of 
  Lasius 
  demonstrated 
  that 
  synizesis 
  is 
  

   followed 
  by 
  the 
  appearance 
  of 
  the 
  haploid 
  number 
  of 
  chromatin 
  threads, 
  and 
  

   the 
  differentiation 
  of 
  nurse 
  cells 
  from 
  functional 
  oocytes; 
  and 
  the 
  oocyte 
  

   nucleus 
  remains 
  in 
  the 
  " 
  confused 
  " 
  stage 
  till 
  immediately 
  before 
  it 
  is 
  laid. 
  

  

  (5) 
  The 
  Secondary 
  Nuclei. 
  — 
  Secondary 
  nuclei 
  have 
  been 
  described 
  in 
  

   Synergus 
  (Cynipid) 
  and 
  Formica 
  rufa, 
  and 
  their 
  genesis 
  has 
  been 
  examined 
  ; 
  

   my 
  conclusions 
  with 
  regard 
  to 
  their 
  origin 
  and 
  fate 
  are, 
  that 
  in 
  both 
  the 
  

   case 
  of 
  Synergus 
  and 
  Formica, 
  they 
  arise 
  from 
  nuclear 
  particles, 
  the 
  ejection 
  

   of 
  which 
  synchronises 
  with 
  a 
  diminution 
  of 
  staining 
  capacity 
  in 
  the 
  

   germinal 
  vesicle. 
  These 
  migrate 
  to 
  the 
  cytoplasm, 
  fragment, 
  and 
  acquire 
  an 
  

   enclosing 
  membrane 
  ; 
  they 
  are 
  transitory 
  structures. 
  Similar 
  conclusions 
  

   have 
  been 
  recorded 
  by 
  Hegner 
  in 
  regard 
  to 
  Apanteles 
  and 
  Bhodites 
  ignota. 
  

  

  (6) 
  The 
  Oosorna. 
  — 
  The 
  Oosoma, 
  or 
  so-called 
  germ-cell 
  determinant, 
  is 
  not 
  

   of 
  nuclear 
  origin, 
  as 
  believed 
  formerly 
  by 
  Hegner 
  and 
  Silvestri, 
  but 
  arises, 
  as 
  

   Gatenby 
  affirms, 
  from 
  cytoplasmic 
  granules 
  which 
  are 
  not 
  mitochondrial. 
  

  

  The 
  present 
  research 
  was 
  commenced 
  at 
  Birkbeck 
  College. 
  The 
  greater 
  

   part 
  has 
  been 
  conducted 
  at 
  the 
  Imperial 
  College. 
  I 
  must 
  express 
  my 
  thanks 
  

   to 
  Prof. 
  MacBride, 
  who 
  has 
  kindly 
  read 
  through 
  the 
  MS., 
  and 
  assisted 
  me 
  

   with 
  helpful 
  criticism. 
  To 
  Prof. 
  Doncaster, 
  of 
  Liverpool 
  — 
  whose 
  kindness 
  in 
  

   sending 
  material 
  of 
  Neuroterus 
  for 
  a 
  previous 
  paper 
  first 
  directed 
  my 
  

   attention 
  to 
  the 
  cytological 
  interest 
  of 
  the 
  Hymenoptera 
  — 
  I 
  owe 
  special 
  

   gratitude, 
  for 
  continuoiis 
  help 
  with 
  regard 
  to 
  bibliography, 
  and 
  suggestive 
  

   advice 
  throughout. 
  

  

  BIBLIOGRAPHY. 
  

  

  (This 
  list 
  is 
  not 
  a 
  complete 
  bibliography, 
  but 
  contains 
  all 
  the 
  more 
  important 
  papers 
  

  

  cited 
  in 
  the 
  text.) 
  

  

  Agar, 
  W. 
  E., 
  "The 
  Spermatogenesis 
  of 
  Lepidosiren 
  paradoxa," 
  'Q.J.M.S.,' 
  vol. 
  57, 
  1911. 
  

   Armbruster, 
  L., 
  " 
  Chromosomen 
  Verhaltnisse 
  bei 
  der 
  Spermatogenese 
  solitairer 
  Apiden," 
  

   ' 
  Arch. 
  Zellforsch.,' 
  vol. 
  11, 
  1913. 
  

  

  