﻿268 
  Mr. 
  L. 
  T. 
  Hogben. 
  

  

  Respiration 
  Experiment. 
  

  

  Table 
  XII. 
  — 
  Phaseolus. 
  

  

  Date. 
  

  

  Temperature, 
  C. 
  

  

  CO 
  per 
  grm., 
  dry 
  weight 
  

   per 
  hour, 
  c.c. 
  

  

  Remarks. 
  

  

  4xi.l9 
  

  

  5. 
  xi.l9 
  

  

  6. 
  xi.l9 
  

  

  11°-12° 
  

   11°-12° 
  

   10°-11° 
  

  

  1-40 
  "I 
  

   0-85 
  I 
  

   0-77 
  J 
  

  

  Sown 
  29.x. 
  19. 
  Dry 
  weight, 
  

   '14 
  grm. 
  Fresh 
  weight, 
  

   '74 
  grm. 
  

  

  Studies 
  on 
  Synapsis. 
  I. 
  — 
  Oogenesis 
  in 
  the 
  Hymenoptera. 
  

  

  By 
  Lancelot 
  T. 
  Hogbkn, 
  M.A. 
  (Cantab.), 
  B.Sc. 
  (Lecturer 
  in 
  Zoology, 
  

   Imperial 
  College 
  of 
  Science, 
  London). 
  

  

  (Communicated 
  by 
  Prof. 
  E. 
  W. 
  McBride, 
  F.R.S. 
  Eeceived 
  November 
  5, 
  1919.) 
  

  

  [Plates 
  4-9.] 
  

  

  For 
  establishing 
  a 
  correlation 
  between 
  genetic 
  and 
  cytological 
  phenomena, 
  

   the 
  Hymenoptera 
  furnish 
  a 
  series 
  of 
  forms 
  which 
  offer 
  fertile 
  possibilities 
  ; 
  

   the 
  production 
  of 
  males 
  from 
  eggs 
  which 
  segment 
  without 
  fertilisation 
  

   makes 
  it 
  possible 
  to 
  state 
  definitely 
  the 
  point 
  in 
  the 
  germ 
  cycle 
  at 
  which 
  

   the 
  determination 
  of 
  sex 
  is 
  effected. 
  While, 
  however, 
  much 
  work 
  has 
  been 
  

   done 
  from 
  the 
  cytological 
  standpoint 
  in 
  connection 
  with 
  the 
  group, 
  our 
  

   knowledge 
  is 
  still 
  inadequate 
  with 
  respect 
  to 
  those 
  species 
  which 
  produce 
  

   females 
  as 
  well 
  as 
  males 
  by 
  parthenogenesis. 
  What 
  little 
  is 
  known 
  of 
  this 
  

   subject 
  has 
  been 
  derived 
  exclusively 
  from 
  a 
  study 
  of 
  the 
  polar 
  and 
  cleavage 
  

   mitoses 
  ; 
  and 
  in 
  view 
  of 
  the 
  importance 
  of 
  treating 
  the 
  germ 
  cell 
  cycle 
  as 
  

   a 
  whole, 
  and 
  also 
  of 
  the 
  unfavourable 
  material 
  which 
  heavily-yolked 
  ova 
  

   necessarily 
  afford, 
  it 
  seemed 
  desirable 
  to 
  investigate 
  oogenesis 
  in 
  typical 
  and 
  

   completely 
  agamic 
  Hymenoptera, 
  more 
  especially 
  because 
  data 
  relating 
  to 
  

   the 
  maturation 
  prophases 
  of 
  the 
  female 
  germ 
  cells 
  in 
  insects 
  are 
  much 
  less 
  

   numerous 
  than 
  in 
  the 
  case 
  of 
  spermatogenesis. 
  The 
  original 
  purpose 
  of 
  the 
  

   author 
  in 
  pursuing 
  the 
  present 
  investigation 
  arose 
  out 
  of 
  previous 
  work 
  on 
  

   nuclear 
  phenomena 
  in 
  the 
  late 
  ovarian 
  oocytes 
  of 
  Neuroterus, 
  which 
  yielded 
  

   indications 
  of 
  post 
  synaptic 
  syndesis. 
  Agar 
  has 
  described 
  a 
  second 
  con- 
  

   jugation 
  of 
  chromosomes 
  after 
  a 
  temporary 
  dissociation 
  of 
  univalents 
  in 
  

   Zepidosiren, 
  unconfirmed 
  hitherto 
  in 
  any 
  other 
  animals 
  ; 
  and 
  since 
  the 
  

  

  