﻿458 
  L. 
  D. 
  CLEARE, 
  JR. 
  

  

  In 
  general 
  the 
  life-cycles 
  of 
  the 
  different 
  species 
  are 
  similar 
  ; 
  the 
  egg 
  period 
  

   is 
  about 
  six 
  days, 
  the 
  larval 
  period 
  varies 
  from 
  three 
  weeks 
  to 
  a 
  month 
  or 
  more, 
  

   and 
  the 
  pupal 
  period 
  lasts 
  about 
  a 
  week. 
  There 
  are, 
  however, 
  distinguishing 
  char- 
  

   acters 
  for 
  the 
  various 
  stages 
  of 
  the 
  different 
  species. 
  

  

  The 
  eggs 
  are 
  oval 
  and 
  flattened. 
  They 
  are 
  deposited 
  in 
  clusters, 
  and 
  beginning 
  

   from 
  the 
  top 
  of 
  the 
  cluster 
  they 
  partly 
  overlap 
  one 
  another 
  after 
  the 
  manner 
  of 
  the 
  

   scales 
  of 
  a 
  fish. 
  The 
  number 
  of 
  eggs 
  in 
  a 
  cluster 
  varies 
  considerably, 
  from 
  two 
  or 
  

   three 
  to 
  as 
  many 
  as 
  100 
  or 
  more, 
  the 
  number 
  usually 
  being 
  between 
  20 
  and 
  40. 
  

  

  The 
  eggs 
  of 
  saccharalis 
  are 
  smaller 
  than 
  those 
  of 
  canella 
  and 
  are 
  generally 
  laid 
  in 
  

   clusters 
  of 
  about 
  five 
  rows, 
  while 
  the 
  eggs 
  of 
  the 
  latter 
  species 
  are 
  generally 
  laid 
  in 
  

   clusters 
  of 
  two 
  or 
  three 
  rows 
  and 
  bear 
  certain 
  red 
  markings 
  which 
  are 
  characteristic. 
  

   When 
  freshly 
  laid 
  the 
  eggs 
  of 
  both 
  species 
  are 
  of 
  a 
  yellowish 
  white 
  colour. 
  After 
  

   the 
  emergence 
  of 
  the 
  larvae 
  the 
  empty 
  shells 
  become 
  translucent 
  white, 
  and 
  their 
  

   appearance 
  has 
  been 
  well 
  likened 
  to 
  a 
  fragment 
  of 
  cast 
  snake-skin. 
  The 
  eggs 
  are 
  

   generally 
  deposited 
  on 
  either 
  side 
  of 
  the 
  green 
  blades, 
  but 
  may 
  also 
  be 
  found 
  on 
  the 
  

   dry 
  trash 
  attached 
  to 
  the 
  cane 
  or 
  on 
  the 
  trash 
  on 
  the 
  ground, 
  and 
  even 
  on 
  blades 
  

   of 
  grass 
  and 
  other 
  weeds 
  not 
  their 
  food-plants. 
  

  

  Parasitised 
  clusters 
  become 
  jet-black 
  after 
  a 
  few 
  days 
  and 
  retain 
  this 
  colour 
  

   even 
  after 
  the 
  emergence 
  of 
  the 
  parasites 
  ; 
  on 
  account 
  of 
  their 
  colour 
  they 
  are 
  easily 
  

   seen 
  in 
  the 
  field. 
  Clusters 
  from 
  which 
  parasites 
  have 
  emerged 
  are 
  readily 
  discernible 
  

   by 
  the 
  holes 
  made 
  in 
  them 
  by 
  the 
  parasites 
  in 
  the 
  act 
  of 
  emerging. 
  

  

  When 
  fully 
  grown 
  the 
  larvae 
  measure 
  about 
  one 
  inch 
  long 
  by 
  one-eighth 
  inch 
  wide, 
  

   and 
  the 
  different 
  species 
  are 
  readily 
  distinguished. 
  In 
  saccharalis 
  the 
  head 
  of 
  the 
  

   larva 
  is 
  very 
  dark 
  brown, 
  almost 
  black, 
  while 
  the 
  larva 
  of 
  canella 
  has 
  a 
  bright 
  yellow 
  

   head 
  and 
  a 
  black 
  or 
  yellow 
  triangular 
  mark 
  on 
  the 
  2nd 
  body 
  segment 
  ; 
  they 
  may 
  

   thus 
  be 
  known 
  as 
  the 
  " 
  black-headed 
  borer 
  " 
  and 
  the 
  " 
  yellow-headed 
  borer," 
  

   respectively. 
  Even 
  the 
  freshly 
  emerged 
  larvae 
  show 
  distinct 
  differences, 
  for 
  while 
  

   those 
  of 
  saccharalis 
  are 
  more 
  or 
  less 
  of 
  the 
  same 
  colour 
  as 
  the 
  fully 
  grown 
  larvae, 
  

   the 
  freshly 
  emerged 
  canella 
  larvae 
  appear 
  to 
  be 
  bright 
  red 
  in 
  colour 
  broken 
  here 
  and 
  

   there 
  by 
  light 
  bands, 
  the 
  head 
  being 
  yellowish 
  brown. 
  The 
  freshly 
  emerged 
  canella 
  

   larvae 
  are 
  also 
  considerably 
  larger 
  than 
  saccharalis 
  larvae 
  of 
  the 
  same 
  age. 
  

  

  The 
  moths, 
  too, 
  are 
  easily 
  distinguished, 
  Diatraea 
  saccharalis 
  being 
  distinctly 
  

   straw-coloured, 
  while 
  D. 
  canella 
  is 
  of 
  a 
  dark 
  grey 
  colour 
  and 
  usually 
  larger. 
  

  

  D. 
  lineolata 
  is 
  only 
  occasionally 
  found 
  feeding 
  on 
  sugar-cane, 
  living 
  normally 
  

   on 
  razor 
  grass 
  (Paspalum 
  plicatum) 
  growing 
  about 
  the 
  dams. 
  The 
  full-grown 
  larvae 
  

   are 
  somewhat 
  like 
  those 
  of 
  D. 
  canella 
  in 
  general 
  appearance, 
  but 
  can 
  be 
  distinguished 
  

   from 
  those 
  insects 
  by 
  the 
  presence 
  of 
  a 
  rod-like 
  black 
  mark 
  on 
  the 
  2nd 
  segment 
  

   instead 
  of 
  a 
  triangular 
  one 
  as 
  in 
  canella. 
  

  

  In 
  addition 
  to 
  sugar-cane, 
  the 
  species 
  of 
  Diatraea 
  are 
  known 
  to 
  feed 
  on 
  a 
  number 
  

   of 
  other 
  plants 
  in 
  this 
  country. 
  Some 
  of 
  these 
  other 
  food-plants 
  are 
  given 
  below 
  : 
  — 
  

  

  Diatraea 
  saccharalis, 
  F., 
  Indian 
  corn, 
  rice, 
  rice-grass 
  or 
  shrimp 
  grass 
  (Luziola 
  

   spruceana), 
  water 
  grass 
  {Paspalum 
  gracile), 
  savannah 
  prickly 
  grass 
  {Paspalum 
  sp.), 
  

   razor 
  grass 
  {Paspalum 
  plicatum 
  and 
  P. 
  virgatum), 
  elephant 
  grass 
  {Panicum 
  elephantipes) 
  

   and 
  a 
  sedge 
  {Cyperus 
  sp.). 
  

  

  Diatraea 
  canella, 
  Hmp. 
  — 
  Indian 
  corn 
  and 
  razor 
  grass 
  {Paspalum 
  plicatum). 
  

  

  Injury 
  and 
  Losses 
  caused 
  by 
  Diatraea. 
  

  

  The 
  injuries 
  caused 
  by 
  the 
  small 
  moth-borers 
  to 
  sugar-cane 
  are 
  not 
  apparent 
  on 
  

   a 
  casual 
  examination. 
  True, 
  a 
  number 
  of 
  joints 
  may 
  be 
  observed 
  to 
  have 
  been 
  bored 
  

   with 
  small 
  holes, 
  but 
  even 
  these 
  give 
  no 
  impression 
  of 
  any 
  extensive 
  damage. 
  It 
  

   is 
  for 
  this 
  reason 
  that 
  the 
  insects 
  are 
  all 
  the 
  more 
  dangerous, 
  for 
  the 
  planter 
  is 
  led 
  to 
  

   underestimate 
  the 
  injury 
  and 
  to 
  take 
  a 
  less 
  serious 
  view 
  of 
  the 
  situation 
  than 
  it 
  

   demands. 
  

  

  