﻿PEOCEEDINGS 
  OF 
  THE 
  FOURTH 
  ENTOMOLOGICAL 
  MEETING 
  299 
  

  

  tions 
  originated 
  the 
  idea 
  of 
  helping 
  nature 
  in 
  the 
  multiplication 
  of 
  these 
  

   useful 
  insects 
  and 
  thus 
  control 
  the 
  boUworms. 
  

  

  It 
  was 
  15 
  years 
  ago 
  that>the 
  theory 
  of 
  checking 
  the 
  bollworms 
  through 
  

   the 
  agency 
  of 
  Microbracon 
  {Rliogas) 
  was 
  first 
  propounded 
  by 
  Lefroy, 
  

   and 
  ever 
  since, 
  this 
  method 
  of 
  dealing 
  with 
  the 
  problem 
  has 
  been 
  advo- 
  

   cated 
  year 
  after 
  year, 
  as 
  the 
  only 
  effective 
  way 
  of 
  eradicating 
  these 
  

   dangerous 
  pests 
  of 
  cottons. 
  It, 
  however, 
  seems 
  strange 
  that, 
  in 
  spite 
  of 
  

   the 
  importance 
  attached 
  to 
  this 
  Braconid, 
  even 
  the 
  preliminary 
  facts, 
  

   the 
  knowledge 
  of 
  which 
  is 
  essential 
  for 
  the 
  successful 
  use 
  of 
  parasitic 
  

   insects, 
  have 
  so 
  long 
  been 
  left 
  uninvestigated. 
  Opinions, 
  more 
  the 
  

   expressions 
  of 
  individual 
  convictions 
  than 
  the 
  results 
  of 
  scientific 
  investi- 
  

   gations, 
  have 
  been 
  put 
  forth, 
  from 
  time 
  to 
  time, 
  some 
  in 
  favour 
  of 
  the 
  

   parasites 
  and 
  others 
  against 
  them 
  ; 
  but 
  no 
  one 
  has 
  attempted 
  to 
  test 
  

   experimentally 
  the 
  efhcacy 
  of 
  this 
  method 
  of 
  control, 
  or 
  has 
  tried 
  to 
  

   work 
  out 
  the 
  problems 
  connected 
  with 
  it. 
  In 
  fact, 
  after 
  15 
  years 
  our 
  

   ignorance 
  is 
  so 
  great 
  that 
  we 
  do 
  not 
  even 
  know 
  the 
  number 
  of 
  eggs 
  laid 
  

   by 
  a 
  female 
  Microbracon 
  lefroyi. 
  In 
  the 
  Punjab 
  the 
  distribution 
  of 
  

   parasite 
  boxes 
  has 
  gone 
  on 
  for 
  a 
  number 
  of 
  years 
  but 
  no 
  definite 
  figures 
  

   are 
  at 
  hand 
  to 
  show 
  whether 
  this 
  means 
  of 
  fighting 
  the 
  bollworms 
  has 
  

   been 
  effective 
  or 
  not. 
  It 
  was, 
  therefore, 
  thought 
  desirable 
  to 
  investigate 
  

   the 
  whole 
  question, 
  and 
  to 
  find 
  out 
  if 
  our 
  methods 
  of 
  dealing 
  with 
  the 
  

   problem 
  were 
  worth 
  continuing. 
  A 
  complete 
  knowledge 
  of 
  the 
  life- 
  

   history, 
  bionomics 
  and 
  behaviour 
  of 
  a 
  pest, 
  and 
  its 
  parasites, 
  in 
  nature 
  

   and 
  under 
  domestication, 
  is 
  an 
  essential 
  preliminary 
  to 
  an 
  effective 
  

   campaign 
  against 
  a 
  noxious 
  insect. 
  A 
  number 
  of 
  experiments 
  was 
  

   started 
  to 
  test 
  the 
  efficacy 
  of 
  Microbracon 
  as 
  a 
  check 
  against 
  the 
  boll- 
  

   worms 
  and 
  a 
  large 
  number 
  of 
  these 
  parasites 
  was 
  bred 
  in 
  the 
  laboratory. 
  

  

  Dealing 
  with 
  the 
  causes 
  that 
  brought 
  about 
  the 
  reduction 
  in 
  the 
  

   number 
  of 
  Microbracon, 
  Lefroy 
  remarks 
  : 
  — 
  " 
  The 
  only 
  abnormal 
  circum- 
  

   stances 
  that 
  I 
  can 
  find 
  is 
  the 
  extreme 
  cold 
  of 
  the 
  preceding 
  winter, 
  a 
  

   cold 
  which 
  may 
  have 
  destroyed 
  Rliogas 
  while 
  leaving 
  the 
  bollworms," 
  

   and 
  our 
  observations 
  support 
  this 
  view. 
  Microbracon 
  seems 
  to 
  be 
  more 
  

   susceptible 
  to 
  low 
  temperatures 
  than 
  the 
  bollworms. 
  Thus 
  its 
  numbers 
  

   are 
  very 
  much 
  reduced 
  in 
  winter 
  and 
  it 
  again 
  appears 
  very 
  late 
  in 
  summer. 
  

   This 
  gives 
  the 
  bollworm 
  a 
  start. 
  The 
  abovementioned 
  fact 
  brought 
  

   us 
  face 
  to 
  face 
  with 
  the 
  question 
  of 
  breeding 
  this 
  parasite 
  throughout 
  

   the 
  winter 
  so 
  as 
  to 
  have 
  a 
  fair 
  supply 
  of 
  it 
  at 
  the 
  very 
  time 
  that 
  boll- 
  

   worms 
  appear 
  on 
  cotton. 
  

  

  Moreover, 
  so 
  far, 
  the 
  parasites 
  when 
  required 
  for 
  distribution 
  among 
  

   the 
  Zamindars 
  were 
  collected 
  from 
  the 
  fields 
  and 
  this 
  necessitated 
  the 
  

   examination 
  of 
  a 
  very 
  large 
  number 
  of 
  bolls 
  to 
  discover 
  those 
  containing 
  

   parasitized 
  caterpillars. 
  This 
  process 
  is 
  essentially 
  wasteful 
  and 
  cum- 
  

  

  