﻿244 
  PROCEEDINGS 
  OF 
  THE 
  FOTTRTH 
  ENTOMOLOGICAL 
  MEETING 
  

  

  bins 
  which 
  were 
  filled 
  with 
  wheat 
  rose 
  as 
  high 
  as 
  113° 
  F. 
  and 
  was 
  

   always 
  a 
  few 
  degrees 
  higher 
  than 
  that 
  of 
  the 
  empty 
  bins. 
  It 
  was 
  also 
  

   found 
  that 
  this 
  high 
  temperature 
  did 
  not 
  ai^ect 
  adversely 
  the 
  insect 
  

   life 
  in 
  the 
  bins. 
  This 
  fact 
  is 
  very 
  remarkable, 
  because 
  Bradwell 
  in 
  

   Proceedings 
  Hmvaii 
  Ento7nol6gical 
  Society 
  (Vol. 
  Ill, 
  pp. 
  506-509) 
  states 
  

   that 
  110° 
  F. 
  kept 
  long 
  enough 
  to 
  penetrate 
  the 
  tissues 
  of 
  the 
  insects 
  

   will 
  kill 
  insect 
  pests 
  of 
  the 
  stored 
  grain. 
  

  

  The 
  two 
  main 
  features 
  of 
  the 
  problems 
  at 
  the 
  elevator 
  are 
  : 
  — 
  

  

  1. 
  That 
  the 
  grain 
  was 
  infected 
  before 
  it 
  was 
  brought 
  to 
  the 
  elevator 
  

   last 
  year 
  and 
  that 
  the 
  method 
  of 
  cleaning 
  the 
  grain 
  by 
  air-blast 
  was 
  

   not 
  effective 
  in 
  removing 
  all 
  the 
  stages 
  of 
  the 
  insects 
  attacking 
  it. 
  

  

  2. 
  That 
  the 
  construction 
  of 
  the 
  bins 
  is 
  such 
  that 
  they 
  can 
  easily 
  be 
  

   rendered 
  insect-proof. 
  

  

  Therefore 
  the 
  problem 
  of 
  safe 
  storage 
  in 
  the 
  elevator 
  reduces 
  itself 
  

   to 
  this 
  — 
  the 
  grain 
  to 
  be 
  stored 
  should 
  be 
  free 
  from 
  all 
  stages 
  of 
  insects 
  

   before 
  it 
  is 
  run 
  into 
  the 
  bins 
  or 
  should 
  be 
  rendered 
  free 
  from 
  insects 
  

   after 
  it 
  has 
  been 
  stored 
  in 
  the 
  bins. 
  

  

  Fumigation 
  of 
  a 
  bin 
  containing 
  6,000 
  maunds 
  of 
  wheat 
  with 
  carbon 
  

   bisulphide 
  or 
  hydrocyanic 
  acid 
  gas 
  is 
  full 
  of 
  risks. 
  Moreover 
  for 
  any 
  

   of 
  these 
  gases 
  to 
  penetrate 
  all 
  through 
  the 
  column 
  of 
  wheat, 
  50 
  feet 
  

   deep 
  and 
  about 
  17 
  feet 
  in 
  diameter, 
  we 
  should 
  allow 
  more 
  than 
  48 
  hours 
  

   exposure. 
  The 
  escape 
  of 
  the 
  gas 
  will 
  also 
  be 
  a 
  slow 
  process 
  and 
  even 
  

   if 
  the 
  manhole 
  at 
  the 
  top 
  of 
  the 
  bin 
  is 
  opened, 
  the 
  gas 
  will 
  take 
  a 
  long 
  

   time 
  completely 
  to 
  get 
  out 
  of 
  the 
  entire 
  bin. 
  Thus 
  a 
  greater 
  part 
  of 
  

   the 
  grain 
  would 
  be 
  surrounded 
  by 
  a 
  poisonous 
  atmosphere 
  for 
  over 
  4 
  

   days 
  : 
  an 
  interval 
  in 
  which 
  carbon 
  bisulphide 
  is 
  definitely 
  known 
  to 
  

   affect 
  the 
  germinating 
  capacity 
  of 
  wheat. 
  The 
  cost 
  of 
  this 
  operation 
  

   will 
  be 
  Rs. 
  63 
  for 
  carbon 
  bisulphide 
  at 
  the 
  rate 
  of 
  Re. 
  1-4 
  per 
  lb., 
  and 
  

   about 
  Rs. 
  35 
  for 
  hydrocyanic 
  acid 
  gas 
  per 
  bin. 
  

  

  On 
  the 
  other 
  hand 
  if 
  some 
  simple 
  process 
  of 
  killing 
  the 
  insects 
  in 
  the 
  

   wheat, 
  that 
  is 
  brought 
  in, 
  could 
  be 
  discovered, 
  and 
  the 
  v.heat 
  cleaned 
  

   of 
  insects 
  before 
  it 
  is 
  stored, 
  the 
  problem 
  will 
  be 
  much 
  simplified. 
  

  

  Superheating 
  is 
  thought 
  to 
  be 
  the 
  best, 
  safest 
  and 
  cheapest, 
  and 
  

   it 
  is 
  possible 
  to 
  plan 
  out 
  an 
  arrangement 
  for 
  heating 
  the 
  grain 
  before 
  

   it 
  is 
  run 
  into 
  the 
  bins. 
  The 
  germinating 
  capacity 
  of 
  the 
  grain 
  is 
  not 
  

   at 
  all 
  impaired 
  at 
  the 
  temperature 
  at 
  which 
  insects 
  die 
  (see 
  Table 
  III 
  

   attached). 
  

  

  Temperature 
  has 
  a 
  direct 
  influence 
  on 
  insect 
  metabolism 
  and 
  with 
  

   its 
  rise 
  their 
  activities 
  increase 
  till 
  an 
  optimum 
  is 
  reached. 
  A 
  few 
  

   degrees 
  above 
  this 
  limit 
  however 
  imperils 
  their 
  life. 
  " 
  At 
  30° 
  C 
  to 
  40"^ 
  

   C 
  (86° 
  to 
  104° 
  F.) 
  the 
  insects 
  are 
  very 
  active, 
  especially 
  the 
  adults. 
  This 
  

   activity 
  increases 
  with 
  the 
  increase 
  in 
  temperature, 
  until 
  the 
  insects 
  

  

  