﻿34 
  ROBERT 
  VEITCH. 
  

  

  pallipes 
  is 
  smaller 
  and 
  carries 
  smaller 
  teeth, 
  on 
  the 
  margin. 
  The 
  larval 
  stage 
  

   probably 
  lasts 
  for 
  three 
  years 
  or 
  longer 
  and 
  the 
  pupal 
  stage 
  for 
  nine 
  or 
  ten 
  days. 
  

  

  The 
  most 
  interesting 
  point 
  in 
  the 
  life-history 
  of 
  this 
  species 
  is 
  the 
  fact 
  that 
  it 
  

   feeds 
  voraciously 
  on 
  the 
  white 
  grubs 
  of 
  Rhopaea 
  vestita, 
  and 
  it 
  is 
  undoubtedly 
  one 
  

   of 
  the 
  most 
  important 
  factors 
  holding 
  that 
  pest 
  in 
  check. 
  It 
  has 
  been 
  observed 
  

   eating 
  grubs 
  in 
  the 
  field, 
  and 
  in 
  a 
  prolonged 
  laboratory 
  experiment 
  it 
  was 
  found 
  

   to 
  consume 
  on 
  an 
  average 
  one 
  grub 
  a 
  week 
  ; 
  in 
  the 
  experiment 
  referred 
  to, 
  the 
  

   wireworms 
  were 
  placed 
  in 
  tins 
  containing 
  rich 
  soil, 
  a 
  white 
  grub 
  and 
  a 
  piece 
  of 
  

   fresh 
  cane, 
  thus 
  giving 
  them 
  the 
  choice 
  of 
  animal 
  food, 
  living 
  vegetable 
  matter 
  

   and 
  decaying 
  vegetable 
  tissue 
  or 
  humus. 
  The 
  animal 
  food 
  was 
  almost 
  invariably 
  

   preferred 
  by 
  this 
  species. 
  

  

  The 
  Sugar-Cane 
  Army-Worm 
  (Cwphis 
  unipuncta, 
  Haw.). 
  

  

  The 
  caterpillars 
  of 
  this 
  Noctuid 
  moth 
  frequently 
  appear 
  in 
  considerable 
  numbers, 
  

   and 
  are 
  responsible 
  for 
  an 
  appreciable 
  amount 
  of 
  damage 
  to 
  the 
  younger 
  crops. 
  

   The 
  caterpillars 
  can 
  be 
  found 
  all 
  the 
  year 
  round, 
  but 
  generally 
  are 
  most 
  abundant 
  

   in 
  the 
  cooler 
  months. 
  This 
  pest 
  is 
  a 
  notorious 
  enemy 
  of 
  maize 
  and 
  other 
  cereals 
  

   in 
  the 
  United 
  States, 
  but 
  fortunately 
  the 
  damage 
  in 
  Fiji 
  has 
  never 
  reached 
  serious 
  

   dimensions. 
  

  

  The 
  most 
  extensive 
  outbreak 
  of 
  this 
  insect 
  in 
  the 
  writer's 
  experience 
  in 
  Fiji 
  

   occurred 
  in 
  May 
  and 
  June 
  1918, 
  in 
  young 
  plant 
  fields 
  six 
  to 
  ten 
  weeks 
  old. 
  The 
  

   caterpillars 
  were 
  in 
  large 
  numbers 
  on 
  ten 
  plantations 
  in 
  the 
  Lautoka 
  and 
  Rarawai 
  

   Mill 
  districts 
  ; 
  no 
  damage 
  was 
  observed 
  in 
  cane 
  older 
  than 
  nine 
  months, 
  and 
  with 
  

   one 
  exception 
  the 
  attacks 
  were 
  confined 
  to 
  plant 
  crops. 
  

  

  The 
  army- 
  worms 
  shelter 
  during 
  the 
  day 
  in 
  the 
  folded 
  leaves 
  of 
  the 
  central 
  shoot 
  

   of 
  the 
  cane 
  plant, 
  and 
  after 
  dusk 
  they 
  move 
  out 
  on 
  to 
  the 
  tips 
  of 
  the 
  leaves, 
  where 
  

   they 
  feed 
  ; 
  when 
  they 
  are 
  present 
  in 
  large 
  numbers 
  they 
  frequently 
  strip 
  the 
  leaves 
  

   right 
  down 
  to 
  the 
  midrib, 
  thus 
  severely 
  retarding 
  the 
  development 
  of 
  the 
  young 
  

   plant. 
  The 
  young 
  caterpillars 
  feed 
  on 
  the 
  leaves 
  of 
  tender 
  grasses, 
  until 
  they 
  are 
  

   able 
  to 
  attack 
  the 
  harder 
  tissue 
  of 
  the 
  cane 
  leaves. 
  There 
  are 
  usually 
  five 
  moults 
  

   at 
  intervals 
  of 
  three 
  to 
  five 
  days, 
  .the 
  caterpillar 
  being 
  full-grown 
  in 
  three 
  weeks. 
  

   The 
  full-grown 
  caterpillar 
  is 
  36 
  to 
  39 
  mm. 
  in 
  length, 
  and 
  is 
  greenish 
  brown 
  in 
  colour. 
  

   When 
  ready 
  to 
  pupate 
  it 
  enters 
  the 
  soil 
  and 
  forms 
  an 
  earthern 
  cell 
  at 
  a 
  depth 
  of 
  

   two 
  or 
  three 
  inches, 
  and 
  inside 
  this 
  it 
  pupates 
  a 
  few 
  days 
  later. 
  The 
  pupal 
  stage 
  

   lasts 
  ten 
  or 
  eleven 
  days. 
  

  

  This 
  pest 
  is 
  well 
  held 
  in 
  check 
  by 
  its 
  enemies, 
  and 
  its 
  attacks 
  rapidly 
  die 
  down, 
  

   for 
  parasites 
  and 
  predators 
  take 
  a 
  heavy 
  toll 
  of 
  it. 
  The 
  minah 
  bird 
  destroys 
  

   numbers 
  of 
  the 
  caterpillars, 
  and 
  a 
  hornet 
  (Polistes 
  macaensis, 
  F.) 
  kills 
  even 
  more 
  ; 
  

   the 
  imago 
  of 
  the 
  latter 
  is 
  very 
  fond 
  of 
  the 
  caterpillars, 
  which 
  also 
  form 
  an 
  important 
  

   item 
  in 
  the 
  food 
  given 
  to 
  its 
  grubs. 
  The 
  Tachinid 
  fly, 
  Sturmia 
  bimaculata, 
  Htg., 
  

   and 
  a 
  Braconid 
  (Apanteles 
  sp.) 
  have 
  been 
  bred 
  from 
  this 
  species 
  of 
  army- 
  worm, 
  and 
  

   the 
  larvae 
  and 
  adults 
  of 
  various 
  Carabidae 
  have 
  been 
  found 
  to 
  feed 
  on 
  the 
  cater- 
  

   pillars. 
  Natural 
  enemies 
  are 
  usually 
  sufficient 
  to 
  hold 
  this 
  species 
  in 
  check, 
  but 
  

   in 
  the 
  event 
  of 
  a 
  serious 
  outbreak 
  resulting 
  from 
  a 
  combination 
  of 
  circumstances 
  

   unfavourable 
  to 
  the 
  natural 
  enemies 
  it 
  could 
  be 
  controlled 
  by 
  the 
  use 
  of 
  poisoned 
  

   sprays. 
  

  

  