﻿41.— 
  PRELIMINARY 
  OBSERVATIONS 
  ON 
  THE 
  OVIPOSITION 
  

   AND 
  LIFE-HISTORY 
  OF 
  MICROBRACON 
  LEFROYI, 
  A 
  

   - 
  BRACONID 
  PARASITE 
  OF 
  EARIAS 
  INSULANA. 
  

  

  By 
  M. 
  Afzal 
  Husain, 
  M.A., 
  (Cantab.), 
  Government 
  Entomologist, 
  Pun- 
  

   jab, 
  and 
  Umrao 
  Bahadur 
  Mathur, 
  L.Ag., 
  Agricultural 
  Assistant, 
  

   The 
  Punjab 
  Agricultural 
  College, 
  Lyallpur. 
  

  

  Introductory. 
  The 
  spotted 
  Bollworms 
  — 
  • 
  Earias 
  insidana, 
  Boisd., 
  and 
  

   E.fabia, 
  Stoll 
  — 
  — 
  have, 
  for 
  many 
  years, 
  been 
  the 
  worst 
  pests 
  of 
  cottons 
  

   in 
  the 
  Punjab. 
  They 
  are 
  of 
  general 
  occurrence 
  throughout 
  the 
  Province 
  

   and 
  not 
  a 
  field 
  in 
  the 
  whole 
  of 
  the 
  cotton-growing 
  tract 
  is 
  free 
  from 
  their 
  

   attack. 
  They 
  make 
  their 
  appearance 
  every 
  year 
  and 
  are 
  so 
  commonly 
  

   met 
  with 
  that 
  the 
  Zamindar 
  has 
  learnt 
  to 
  regard 
  their 
  presence 
  as 
  nothing 
  

   unusual, 
  and 
  a 
  damage 
  up 
  to 
  10 
  per 
  cent, 
  has 
  come^to 
  be 
  regarded 
  as 
  

   not 
  abnormal. 
  During 
  some 
  years, 
  however, 
  these 
  bollworms 
  increase 
  

   so 
  tremendously 
  that 
  they 
  devastate 
  almost 
  the 
  entire 
  cotton 
  crop 
  

   and 
  cause 
  great 
  economic 
  disaster. 
  In 
  1905 
  the 
  loss 
  to 
  this 
  Province 
  

   caused 
  by 
  the 
  ravages 
  of 
  these 
  insects 
  was 
  estimated 
  at 
  2 
  to 
  3 
  crores 
  of 
  

   rupees. 
  

  

  The 
  study 
  of 
  the 
  causes 
  of 
  the 
  failure 
  of 
  the 
  cotton 
  crop 
  in 
  1905 
  led 
  

   to 
  the 
  belief 
  that 
  during 
  normal 
  years 
  the 
  parasites 
  of 
  the 
  bollworms 
  

   keep 
  them 
  in 
  check 
  so 
  effectively 
  that 
  their 
  numbers 
  do 
  not 
  increase 
  

   sufficiently 
  to 
  do 
  great 
  damage. 
  Lefroy, 
  who 
  carried 
  on 
  the 
  investiga- 
  

   tion 
  in 
  1905, 
  says 
  : 
  — 
  " 
  The 
  peculiar 
  feature 
  of 
  the 
  present 
  case 
  is 
  the 
  

   absence 
  of 
  paradtes 
  ; 
  this 
  is 
  very 
  marked 
  and 
  is 
  a 
  most 
  striking 
  circum- 
  

   stance. 
  Normally 
  when 
  the 
  bollworms 
  increase 
  with 
  plentiful 
  food, 
  

   their 
  parasites 
  increase 
  more 
  rapidly, 
  and 
  keep 
  down 
  their 
  numbers. 
  

   The 
  parasites 
  are 
  in 
  fact, 
  the 
  principal 
  check 
  on 
  their 
  increase, 
  and 
  

   had 
  they 
  been 
  present 
  in 
  normal 
  quantities, 
  the 
  bollworms 
  would 
  

   probably 
  have 
  been 
  checked. 
  "(1) 
  

  

  Of 
  the 
  parasites 
  of 
  the 
  bollworms 
  the 
  one 
  to 
  which 
  the 
  credit 
  of 
  

   being 
  the 
  most 
  effective 
  has 
  been 
  given, 
  is 
  " 
  a 
  small 
  Ichneumon 
  fly 
  

   {Rhogas 
  lefroyi, 
  Ashm.) 
  which 
  is 
  the 
  principal 
  and 
  the 
  most 
  abundant 
  

   one, 
  increasing 
  rapidly 
  and 
  destroying 
  a 
  very 
  large 
  proportion 
  of 
  bol- 
  

   worms 
  in 
  normal 
  years."(l) 
  Thus 
  according 
  to 
  Lefroy 
  (1) 
  the 
  serious 
  

   failure 
  of 
  the 
  cotton 
  crop 
  in 
  1905 
  was 
  the 
  result 
  of 
  great 
  and 
  sudden 
  

   reduction 
  in 
  the 
  numbers 
  of 
  this 
  parasite; 
  he 
  says: 
  — 
  "The 
  most 
  import- 
  

   ant 
  parasite 
  which 
  generally 
  checks 
  the 
  bollworms 
  was, 
  I 
  believe, 
  entirely 
  

   absent 
  from 
  the 
  majority 
  of 
  the 
  cotton 
  districts." 
  From 
  these 
  considera- 
  

  

  ( 
  298 
  ) 
  

  

  