﻿206 
  R. 
  J. 
  TILLYARD. 
  

  

  and 
  December 
  of 
  that 
  year, 
  to 
  pay 
  a 
  series 
  of 
  visits 
  to 
  this 
  locality, 
  digging 
  up 
  the 
  

   ground 
  all 
  round 
  the 
  cottage, 
  and 
  especially 
  in 
  the 
  vicinity 
  of 
  the 
  outhouse 
  and 
  around 
  

   a 
  number 
  of 
  trees 
  near 
  by. 
  We 
  found 
  a 
  number 
  of 
  rather 
  large 
  cocoons 
  made 
  of 
  sand 
  ; 
  

   but 
  from 
  these 
  there 
  emerged 
  a 
  very 
  common 
  Noctuid 
  moth, 
  whose 
  caterpillars 
  

   we 
  also 
  sometimes 
  found 
  at 
  the 
  bases 
  of 
  tree-trunks. 
  The 
  only 
  other 
  insects 
  in 
  the 
  

   soil 
  appeared 
  to 
  be 
  various 
  larvae 
  of 
  Diptera, 
  Brachycera, 
  some 
  cocoons 
  of 
  Thynnid 
  

   wasps, 
  and 
  a 
  number 
  of 
  different 
  species 
  of 
  Coleopterous 
  larvae 
  of 
  the 
  family 
  Scara.- 
  

   baeidae. 
  It 
  never 
  occurred 
  to 
  either 
  of 
  us 
  that 
  one 
  of 
  these 
  apparently 
  Scarabaeid 
  

   larvae 
  was 
  in 
  reality 
  the 
  unknown 
  larva 
  of 
  Ithone, 
  and 
  we 
  certainly 
  dug 
  up 
  and 
  threw 
  

   aside 
  quite 
  a 
  number 
  of 
  them, 
  so 
  set 
  were 
  our 
  minds 
  on 
  finding 
  a 
  larva 
  which 
  would 
  

   conform 
  to 
  the 
  primitive 
  Planipennian 
  type, 
  as 
  exhibited 
  by 
  the 
  Psychopsidae 
  or 
  

   Hemerobiidae. 
  But 
  in 
  1918, 
  when 
  we 
  succeeded 
  in 
  pairing 
  the 
  adults, 
  it 
  was 
  with 
  

   the 
  greatest 
  astonishment 
  that 
  we 
  saw 
  emerging 
  from 
  the 
  fertile 
  eggs 
  a 
  number 
  of 
  

   tiny 
  white 
  melolonthoid 
  grubs. 
  On 
  making 
  an 
  enlarged 
  drawing 
  of 
  one 
  of 
  these 
  

   under 
  the 
  camera 
  lucida, 
  it 
  was 
  at 
  once 
  seen 
  that 
  the 
  larva 
  of 
  Ithone 
  was 
  a 
  soft-bodied, 
  

   burrowing 
  insect, 
  closely 
  similar 
  to 
  a 
  Scarabaeid 
  larva 
  in 
  general 
  appearance. 
  We 
  

   were 
  then 
  able 
  to 
  recall 
  at 
  once 
  the 
  particular 
  grub 
  which 
  we 
  had 
  dug 
  up 
  time 
  and 
  

   again, 
  and 
  thrown 
  away, 
  but 
  which, 
  it 
  now 
  appeared, 
  was 
  in 
  reality 
  the 
  prize 
  we 
  had 
  

   been 
  searching 
  for. 
  

  

  From 
  that 
  time 
  on, 
  larvae 
  were 
  easily 
  obtained, 
  and 
  we 
  soon 
  found 
  that 
  they 
  

   could 
  be 
  distinguished 
  from 
  all 
  the 
  true 
  Scarabaeid 
  larvae, 
  not 
  only 
  by 
  their 
  detailed 
  

   structure, 
  but 
  especially 
  by 
  a 
  very 
  strong 
  odour 
  of 
  citronella 
  which 
  they 
  gave 
  out, 
  

   and 
  which 
  frequently 
  arose 
  from 
  the 
  soil 
  while 
  we 
  were 
  digging 
  ; 
  when 
  this 
  odour 
  

   was 
  noticed 
  we 
  were 
  sure 
  to 
  get 
  a 
  larva 
  of 
  Ithone 
  in 
  the 
  next 
  spadeful 
  or 
  two 
  of 
  soil. 
  

  

  A 
  further 
  pitfall 
  awaited 
  us 
  through 
  the 
  chance 
  happening 
  that 
  the 
  first 
  pupa 
  

   discovered 
  was 
  lying 
  free 
  in 
  the 
  soil. 
  Again, 
  the 
  similarity 
  of 
  Ithone 
  to 
  the 
  Megalop- 
  

   tera 
  occurred 
  to 
  my 
  mind 
  ; 
  and 
  as 
  the 
  pupa 
  was 
  elongated, 
  not 
  curved 
  round 
  like 
  

   those 
  Planipennian 
  pupae 
  which 
  are 
  enclosed 
  in 
  cocoons, 
  I 
  took 
  it 
  as 
  proof 
  that 
  the 
  

   larva 
  did 
  not 
  spin 
  a 
  cocoon, 
  and 
  said 
  so 
  in 
  my 
  previous 
  papei 
  (1919, 
  p. 
  416). 
  However, 
  

   Mr. 
  Gallard 
  and 
  myself 
  almost 
  simultaneously 
  discovered, 
  shortly 
  afterwards, 
  the 
  

   cocoon 
  of 
  Ithone 
  with 
  the 
  larva 
  inside 
  it, 
  so 
  that 
  I 
  was 
  able 
  to 
  correct 
  this 
  mistake 
  

   by 
  a 
  postscript 
  in 
  the 
  same 
  paper 
  (p. 
  437). 
  

  

  The 
  outline 
  of 
  the 
  life-history 
  was 
  now 
  complete, 
  and 
  it 
  only 
  remained 
  to 
  observe 
  

   the 
  larvae 
  in 
  captivity, 
  study 
  their 
  feeding 
  habits, 
  their 
  methods 
  of 
  burrowing 
  and 
  

   progression, 
  the 
  spinning 
  of 
  the 
  cocoon, 
  and 
  the 
  emergence 
  of 
  the 
  imago 
  from 
  it. 
  

   The 
  discovery 
  of 
  the 
  pupa 
  free 
  from 
  the 
  cocoon, 
  in 
  the 
  soil, 
  was 
  explained 
  when 
  we 
  

   found 
  that 
  the 
  pupa 
  cuts 
  its 
  way 
  out 
  of 
  the 
  cocoon 
  by 
  means 
  of 
  its 
  huge 
  mandibles, 
  

   and 
  travels 
  some 
  way 
  in 
  the 
  soil 
  before 
  disclosing 
  the 
  imago. 
  

  

  I 
  should 
  like 
  here 
  to 
  put 
  on 
  record 
  the 
  large 
  share 
  that 
  Mr. 
  Gallard 
  deserves 
  of 
  

   the 
  credit 
  for 
  the 
  discovery 
  and 
  working 
  out 
  of 
  this 
  life-history. 
  He 
  has 
  been 
  most 
  

   enthusiastic 
  in 
  the 
  work, 
  and 
  has 
  at 
  all 
  times 
  taken 
  upon 
  himself 
  the 
  giant's 
  share 
  

   of 
  the 
  heavy 
  labour 
  of 
  digging 
  the 
  soil, 
  without 
  which 
  no 
  larvae 
  could 
  have 
  been 
  

   obtained. 
  My 
  best 
  thanks 
  are 
  due 
  to 
  him 
  for 
  the 
  very 
  great 
  assistance 
  he 
  has 
  given 
  

   me. 
  I 
  also 
  wish 
  to 
  thank 
  Mr. 
  W. 
  C. 
  Davies, 
  Curator 
  of 
  the 
  Cawthron 
  Institute, 
  

   for 
  the 
  excellent 
  photographs 
  which 
  he 
  has 
  taken 
  of 
  the 
  various 
  stages 
  of 
  the 
  life- 
  

   history 
  ; 
  these 
  have 
  been 
  collected 
  together 
  and 
  are 
  reproduced 
  on 
  Plate 
  iv. 
  The 
  

   text-figures 
  have 
  been 
  prepared 
  by 
  myself, 
  with 
  the 
  aid 
  of 
  an 
  Abbe 
  camera 
  lucida. 
  

  

  The 
  Life-Cycle 
  of 
  Ithone 
  fusca. 
  

  

  The 
  complete 
  life-cycle 
  of 
  Ithone 
  fusca 
  appears 
  generally 
  to 
  last 
  exactly 
  two 
  

   years. 
  When 
  digging 
  the 
  soil 
  during 
  the 
  first 
  two 
  weeks 
  in 
  November, 
  which 
  is 
  the 
  

   period 
  during 
  which 
  the 
  imagines 
  are 
  on 
  the 
  wing, 
  we 
  found 
  plenty 
  of 
  larvae, 
  but 
  no 
  

   pupae. 
  Most 
  of 
  these 
  larvae 
  were 
  from 
  half- 
  to 
  three-quarters 
  grown. 
  As 
  there 
  is 
  

   no 
  record 
  of 
  a 
  second 
  brood, 
  these 
  larvae 
  must 
  last 
  through 
  a 
  second 
  summer, 
  and 
  

  

  