﻿LIFE-HISTORY 
  OF 
  AUSTRALIAN 
  MOTH-LACEWING, 
  ITHONE 
  FUSCA, 
  NEWMAN. 
  207 
  

  

  would 
  not 
  become 
  adults 
  until 
  the 
  following 
  November. 
  Nevertheless, 
  as 
  with 
  

   other 
  Planipennia, 
  it 
  is 
  probable 
  that 
  some, 
  if 
  food 
  were 
  abundant 
  enough, 
  might 
  

   complete 
  their 
  life-cycle 
  in 
  one 
  year, 
  while 
  others, 
  when 
  food 
  is 
  scarce 
  owing 
  to 
  

   drought, 
  may 
  take 
  three 
  years 
  to 
  reach 
  maturity. 
  

  

  The 
  life-cycle 
  is 
  made 
  up 
  as 
  follows, 
  taking 
  as 
  an 
  example 
  an 
  egg 
  laid 
  on 
  

   1st 
  November 
  : 
  — 
  

  

  Stage. 
  Dates. 
  Duration. 
  

  

  Egg 
  . 
  . 
  . 
  . 
  . 
  . 
  1st 
  Nov.-2nd 
  Dec. 
  . 
  . 
  31 
  days 
  (average). 
  

  

  Larva 
  (five 
  instars) 
  . 
  . 
  2nd 
  Dec.-14th 
  Sept. 
  . 
  . 
  1 
  year 
  9 
  J 
  months 
  (average). 
  

  

  Larva 
  in 
  cocoon 
  . 
  . 
  14th 
  Sept.-7th 
  Oct. 
  . 
  . 
  About 
  three 
  weeks. 
  

  

  Pupa 
  in 
  cocoon 
  . 
  . 
  7th 
  Oct.-31st 
  Oct. 
  . 
  . 
  About 
  three 
  weeks. 
  

  

  Imago 
  . 
  . 
  . 
  . 
  . 
  . 
  31st 
  Oct.-2nd 
  Nov. 
  . 
  . 
  Two 
  or 
  three 
  days. 
  

  

  The 
  above 
  are 
  all 
  given 
  as 
  average 
  periods. 
  The 
  eggs 
  may 
  hatch 
  a 
  little 
  sooner 
  

   if 
  the 
  weather 
  is 
  very 
  hot 
  during 
  the 
  embryonic 
  period, 
  or 
  they 
  may 
  be 
  a 
  little 
  retarded 
  

   if 
  the 
  weather 
  becomes 
  cold. 
  The 
  female 
  imago 
  usually 
  pairs 
  within 
  an 
  hour 
  or 
  two 
  

   of 
  emergence, 
  and 
  most 
  of 
  its 
  eggs 
  are 
  laid 
  the 
  same 
  night 
  ; 
  she 
  seldom 
  lives 
  more 
  

   than 
  two 
  days. 
  The 
  male 
  also 
  seldom 
  lives 
  more 
  than 
  two 
  or 
  three 
  days, 
  though 
  I 
  

   have 
  succeeded 
  in 
  keeping 
  them 
  alive 
  for 
  a 
  week. 
  They 
  take 
  no 
  food 
  in 
  the 
  natural 
  

   state, 
  though 
  their 
  mouth-parts 
  are 
  well 
  developed. 
  

  

  No 
  definite 
  times 
  can 
  be 
  given 
  for 
  the 
  separate 
  larval 
  instars, 
  as 
  ecdysis 
  depends 
  

   entirely 
  upon 
  the 
  amount 
  of 
  growth, 
  and 
  this 
  in 
  turn 
  is 
  dependent 
  upon 
  the 
  amount 
  

   of 
  food 
  taken. 
  One 
  or 
  two 
  good 
  meals 
  are 
  enough 
  to 
  enable 
  the 
  larva 
  to 
  grow 
  to 
  its 
  

   full 
  size 
  for 
  any 
  given 
  instar, 
  but 
  many 
  days 
  may 
  pass 
  during 
  which 
  the 
  larva 
  is 
  

   burrowing 
  in 
  the 
  ground 
  without 
  finding 
  any 
  food 
  at 
  all. 
  Consequently, 
  in 
  any 
  

   given 
  brood 
  there 
  are 
  always 
  some 
  larvae 
  which 
  grow 
  much 
  faster 
  than 
  the 
  rest, 
  and 
  

   there 
  are 
  also 
  others 
  which, 
  finding 
  no 
  food 
  at 
  all, 
  die 
  at 
  last 
  from 
  sheer 
  exhaustion. 
  

  

  Emergence 
  of 
  the 
  Imago. 
  

  

  The 
  adult 
  Ithone 
  fusca 
  emerges 
  just 
  about 
  sundown 
  during 
  the 
  fortnight 
  from 
  

   the 
  end 
  of 
  October 
  to 
  the 
  middle 
  of 
  November. 
  The 
  pupa 
  discloses 
  the 
  imago 
  while 
  

   still 
  in 
  the 
  soil 
  ; 
  the 
  imago 
  crawls 
  out 
  with 
  its 
  wings 
  still 
  unexpanded, 
  and 
  makes 
  

   for 
  the 
  nearest 
  post 
  or 
  tree-trunk, 
  up 
  which 
  it 
  climbs 
  to 
  a 
  height 
  of 
  from 
  one 
  to 
  three 
  

   feet. 
  Its 
  wings 
  expand 
  so 
  rapidly 
  that 
  they 
  are 
  generally 
  full} 
  7 
  formed 
  by 
  the 
  time 
  

   the 
  insect 
  has 
  come 
  to 
  rest. 
  They 
  are 
  held 
  outwards 
  away 
  from 
  the 
  body 
  during 
  

   expansion, 
  and 
  are 
  then 
  folded 
  down 
  in 
  a 
  somewhat 
  flattened, 
  roof-wise 
  manner. 
  

   It 
  is 
  very 
  curious 
  to 
  be 
  watching 
  a 
  clear 
  patch 
  of 
  sandy 
  soil 
  and 
  to 
  see, 
  quite 
  suddenly, 
  

   a 
  slight 
  falling 
  in 
  of 
  the 
  sand, 
  so 
  that 
  a 
  small 
  pit 
  is 
  temporarily 
  formed, 
  from 
  the 
  

   middle 
  of 
  which 
  there 
  emerges 
  an 
  adult 
  Ithone, 
  scurrying 
  off 
  almost 
  like 
  a 
  cockroach 
  

   to 
  find 
  a 
  suitable 
  perch 
  to 
  rest 
  and 
  expand 
  its 
  wings. 
  

  

  As 
  soon 
  as 
  the 
  sun 
  is 
  set, 
  the 
  moth-lacewings 
  begin 
  to 
  vibrate 
  their 
  wings 
  very 
  

   slightly 
  but 
  rapidlv, 
  and 
  then 
  take 
  flight. 
  The 
  females, 
  which 
  are 
  always 
  much 
  

   less 
  in 
  number 
  than 
  the 
  males, 
  fly 
  rapidly 
  like 
  ghosts 
  across 
  the 
  bracken 
  and 
  herbage, 
  

   and 
  settle 
  upon 
  some 
  convenient 
  tree-trunk. 
  The 
  males 
  dash 
  hither 
  and 
  thither 
  

   exactly 
  like 
  Hepialid 
  moths, 
  and 
  soon 
  begin 
  to 
  assemble 
  in 
  swarms 
  around 
  the 
  females. 
  

   While 
  on 
  the 
  tree-trunks 
  they 
  will 
  often 
  rush 
  about 
  and 
  circle 
  round 
  and 
  round, 
  

   while 
  at 
  other 
  times 
  they 
  will 
  sit 
  at 
  short 
  distances 
  apart, 
  rapidlv 
  vibrating 
  their 
  

   wings, 
  ready 
  to 
  dash 
  off 
  again 
  at 
  a 
  moment's 
  notice. 
  

  

  Calm 
  evenings 
  or 
  those 
  with 
  a 
  light 
  north-east 
  wind 
  were 
  those 
  which 
  favoured 
  

   the 
  swarming 
  of 
  Ithone. 
  On 
  nights 
  with 
  a 
  cold 
  south 
  or 
  south-east 
  wind, 
  there 
  was 
  

   little 
  or 
  no 
  emergence. 
  Most 
  of 
  the 
  insects 
  selected 
  the 
  west 
  or 
  north-west 
  side 
  of 
  

   the 
  trees, 
  this 
  being 
  the 
  warmest 
  and 
  most 
  sheltered. 
  The 
  largest 
  swarm 
  I 
  noticed 
  

   was 
  on 
  a 
  trunk 
  where 
  three 
  females 
  had 
  settled 
  close 
  together. 
  Around 
  these 
  were 
  

   swarming 
  more 
  than 
  a 
  hundred 
  males. 
  While 
  bottling 
  them 
  and 
  sweeping 
  them 
  

  

  