﻿222 
  R. 
  J. 
  TILLYARD. 
  

  

  Feeding 
  habits 
  of 
  the 
  Larva. 
  

  

  Mr. 
  Gallard 
  and 
  I 
  have 
  both 
  satisfied 
  ourselves 
  that 
  the 
  natural 
  food 
  of 
  this 
  

   larva 
  is 
  the 
  Scarabaeid 
  grubs 
  which 
  it 
  superficially 
  resembles. 
  A 
  dissection 
  of 
  the 
  

   larva 
  shows 
  that 
  it 
  has 
  no 
  true 
  mouth, 
  and 
  that 
  only 
  liquid 
  food 
  can 
  be 
  taken, 
  in 
  the 
  

   same 
  manner 
  as 
  in 
  the 
  case 
  of 
  other 
  Planipennian 
  larvae. 
  No 
  faeces 
  are 
  formed, 
  

   and 
  the 
  structure 
  of 
  the 
  hind 
  gut 
  and 
  anus 
  shows 
  that 
  this 
  part 
  has 
  become 
  specialised 
  

   for 
  the 
  production 
  of 
  silk 
  only. 
  The 
  question, 
  then, 
  was 
  as 
  to 
  what 
  was 
  its 
  natural 
  

   food. 
  A 
  collection 
  of 
  all 
  the 
  forms 
  of 
  animal 
  life 
  inhabiting 
  the 
  sandy 
  soil 
  in 
  which 
  

   Ithone 
  lives 
  yielded 
  only 
  the 
  following 
  results 
  : 
  (a) 
  cocoons 
  of 
  Thynnid 
  wasps 
  ; 
  (b) 
  

   larvae 
  and 
  pupae 
  of 
  Brachycerous 
  Diptera, 
  chiefly 
  Asilidae 
  ; 
  (c) 
  larvae 
  and 
  pupae 
  

   of 
  Coleoptera, 
  chiefly 
  Scarabaeidae 
  ; 
  (d) 
  occasional 
  burrowing 
  Lepidopterous 
  larvae, 
  

   chiefly 
  those 
  of 
  Hepialidae. 
  

  

  That 
  the 
  larvae 
  of 
  Ithone 
  do 
  not 
  normally 
  feed 
  upon 
  (a) 
  or 
  (b) 
  is 
  obvious, 
  these 
  

   two 
  groups 
  being 
  themselves 
  predacious, 
  and 
  most 
  probably 
  attacking 
  Ithone 
  itself 
  

   as 
  well 
  as 
  other 
  larvae. 
  In 
  fact, 
  a 
  Thynnid 
  cocoon 
  has 
  recently 
  been 
  obtained 
  by 
  

   me 
  from 
  a 
  live 
  Ithone 
  larva 
  which 
  was 
  put 
  away 
  in 
  a 
  jar 
  of 
  soil 
  some 
  weeks 
  previously. 
  

   Of 
  (c) 
  and 
  (d) 
  we 
  can 
  say 
  at 
  once 
  that 
  the 
  latter 
  are 
  far 
  too 
  uncommon 
  to 
  supply 
  the 
  

   amount 
  of 
  food 
  necessary 
  for 
  the 
  large 
  number 
  of 
  Ithone 
  larvae 
  present 
  in 
  the 
  soil. 
  

   The 
  only 
  food 
  that 
  is 
  present 
  in 
  the 
  requisite 
  amount 
  is 
  the 
  Coleopterous 
  larvae, 
  of 
  

   which 
  more 
  than 
  ninety 
  per 
  cent, 
  consist 
  of 
  Scarabaeid 
  grubs, 
  more 
  or 
  less 
  closely 
  

   resembling 
  the 
  larva 
  of 
  Ithone. 
  One 
  of 
  these, 
  shown 
  in 
  Plate 
  iv, 
  fig. 
  8, 
  is 
  so 
  like 
  Ithone 
  

   when 
  first 
  dug 
  up 
  that 
  we 
  came 
  to 
  call 
  it 
  the 
  " 
  false 
  Ithone 
  " 
  ; 
  we 
  have 
  not 
  succeeded 
  

   in 
  rearing 
  it 
  to 
  determine 
  to 
  what 
  species 
  it 
  belongs. 
  

  

  On 
  several 
  occasions 
  I 
  placed 
  a 
  number 
  of 
  Scarabaeid 
  larvae 
  in 
  soil 
  in 
  a 
  large 
  j 
  ar 
  

   and 
  then 
  turned 
  out 
  a 
  few 
  Ithone 
  larvae 
  on 
  top 
  of 
  the 
  soil. 
  The 
  Ithone 
  larvae 
  at 
  once 
  

   burrowed 
  rapidly 
  down, 
  and 
  kept 
  working 
  away 
  round 
  and 
  round 
  the 
  jar. 
  Approach- 
  

   ing 
  a 
  Scarab 
  larva, 
  they 
  appear 
  always 
  to 
  burrow 
  down 
  below 
  it, 
  and 
  then 
  work 
  up 
  

   towards 
  it 
  from 
  below. 
  I 
  have 
  not 
  actually 
  succeeded 
  in 
  seeing 
  an 
  Ithone 
  larva 
  

   attack 
  any 
  of 
  its 
  victims, 
  but 
  have 
  no 
  doubt 
  that 
  it 
  is 
  done 
  by 
  an 
  upward 
  stroke, 
  

   j 
  udging 
  by 
  the 
  formation 
  of 
  its 
  mouth-parts 
  . 
  On 
  examining 
  one 
  j 
  ar 
  of 
  larva 
  the 
  follow- 
  

   ing 
  morning, 
  I 
  found 
  all 
  the 
  Scarab 
  larvae 
  killed, 
  one 
  having 
  been 
  sucked 
  almost 
  

   dry, 
  another 
  partly 
  sucked, 
  and 
  the 
  rest 
  having 
  one 
  or 
  more 
  clearly 
  marked 
  wounds 
  

   which 
  had 
  caused 
  their 
  death. 
  One 
  Ithone 
  larva 
  was 
  also 
  wounded, 
  and 
  died 
  later 
  ; 
  

   this 
  may 
  have 
  been 
  from 
  an 
  attack 
  by 
  another 
  Ithone 
  larva, 
  or 
  possibly 
  the 
  wound 
  

   was 
  caused 
  by 
  the 
  jaws 
  of 
  the 
  Scarab 
  larva 
  which 
  it 
  was 
  attacking. 
  Mr. 
  Gallard 
  

   had 
  also 
  observed, 
  on 
  more 
  than 
  one 
  occasion, 
  the 
  death 
  and 
  partial 
  sucking-out 
  of 
  

   Scarab 
  larvae 
  to 
  which 
  Ithone 
  larvae 
  have 
  been 
  given 
  access. 
  

  

  We 
  can 
  only 
  conclude 
  that 
  the 
  principal 
  diet 
  of 
  the 
  larva 
  of 
  Ithone 
  consists 
  of 
  

   Coleopterous 
  larvae, 
  chiefly 
  those 
  of 
  Scarabaeidae 
  ; 
  though 
  this 
  does 
  not 
  preclude 
  

   the 
  probability 
  that 
  they 
  also 
  attack 
  Hepialid 
  and 
  other 
  larvae 
  when 
  hungry. 
  

  

  The 
  Economic 
  Value 
  of 
  the 
  Ithonidae. 
  

  

  The 
  family 
  Ithonidae 
  is 
  widely 
  spread 
  throughout 
  Australia, 
  being 
  found 
  from 
  

   Queensland 
  down 
  into 
  New 
  South 
  Wales 
  and 
  Victoria, 
  and 
  across 
  the 
  central 
  desert 
  

   into 
  Western 
  Australia. 
  One 
  species, 
  Heterithone 
  pallida, 
  Till., 
  is 
  common 
  in 
  many 
  

   localities 
  in 
  Tasmania. 
  The 
  larvae 
  must, 
  therefore, 
  be 
  capable 
  of 
  standing 
  great 
  

   extremes 
  of 
  temperature 
  in 
  the 
  soil. 
  The 
  insects 
  are 
  most 
  abundant 
  along 
  the 
  sandy 
  

   foreshores 
  and 
  wherever 
  the 
  soil 
  is 
  of 
  a 
  light, 
  loose 
  texture 
  suitable 
  for 
  easy 
  burrowing. 
  

   These 
  are 
  also 
  the 
  conditions 
  which 
  best 
  suit 
  the 
  various 
  species 
  of 
  Grass-grub. 
  But, 
  

   just 
  as 
  Scarabaeid 
  grubs 
  are 
  also 
  to 
  be 
  found 
  in 
  heavier 
  soil, 
  so 
  there 
  is 
  evidence 
  that 
  

   Ithone 
  also 
  exists 
  there, 
  though 
  not 
  so 
  abundantly. 
  One 
  species 
  has 
  been 
  taken 
  

   on 
  Mount 
  Tambourine, 
  where 
  the 
  soil 
  is 
  of 
  volcanic 
  origin 
  ; 
  the 
  larva 
  of 
  another 
  

   has 
  been 
  found 
  by 
  Mr. 
  Gallard 
  in 
  a 
  heavy 
  loam 
  at 
  Epping. 
  Isolated 
  records 
  of 
  the 
  

   occurrence 
  of 
  the 
  imago 
  come 
  from 
  many 
  parts 
  of 
  the 
  interior 
  of 
  Australia 
  also, 
  

   so 
  that 
  the 
  insect 
  is 
  by 
  no 
  means 
  confined 
  to 
  the 
  coastal 
  strip. 
  

  

  