﻿190 
  

  

  rilOCEEDINGS 
  OF 
  THK 
  FOUllTH 
  ENTOMOLOGICAL 
  MEETING 
  

  

  Mr. 
  Sen. 
  

  

  Mr. 
  Iyengar. 
  

   Mr. 
  Sen. 
  

  

  Mr. 
  Sen. 
  

  

  Mr. 
  White. 
  

   Mr. 
  Fletcher. 
  

  

  I 
  could 
  iiot 
  give 
  this 
  a 
  sufficient 
  trial. 
  I 
  tried 
  coconut 
  oil, 
  and 
  a 
  

   few 
  other 
  oils. 
  The 
  point 
  is 
  that 
  the 
  expense 
  of 
  a 
  larger 
  quantity 
  

   is 
  counteracted 
  by 
  its 
  lower 
  volatility. 
  

  

  I 
  cannot 
  understand 
  i^s 
  efficacy 
  under 
  natural 
  conditions. 
  Para- 
  

   forniol 
  will 
  beat 
  this 
  hollow. 
  

  

  As 
  has 
  been 
  already 
  mentioned 
  in 
  the 
  introductory 
  portion, 
  the 
  

   results 
  are 
  presented 
  only 
  as 
  an 
  indication 
  of 
  the 
  possibilities 
  of 
  insoluble 
  

   salts, 
  non-poisonous 
  to 
  human 
  beings. 
  Soluble 
  substances 
  would 
  involve 
  

   wastage. 
  The 
  activities 
  of 
  the 
  larvae 
  being 
  mainly 
  connected 
  with 
  the 
  

   surface 
  area, 
  a 
  substance 
  would 
  be 
  necessary 
  which 
  would 
  keep 
  to 
  the 
  

   surface 
  without 
  entering 
  into 
  the 
  solution. 
  Under 
  laboratory 
  conditions 
  

   HgCl, 
  if 
  it 
  can 
  be 
  kept 
  on 
  the 
  surface, 
  will 
  generally 
  remain 
  efiective 
  for 
  

   an 
  indefinite 
  period, 
  being 
  neither 
  soluble 
  nor 
  volatile. 
  In 
  the 
  absence 
  

   of 
  experiments 
  I 
  caimot 
  claim 
  its 
  present 
  suitability 
  on 
  a 
  n,eld 
  scale. 
  1 
  

   have 
  already 
  considered, 
  in 
  the 
  latter 
  portion 
  of 
  my 
  paper, 
  the 
  difficul- 
  

   ties 
  in 
  the 
  way 
  of 
  keeping 
  the 
  salt 
  particles 
  floating, 
  and 
  mentioned 
  

   some 
  of 
  the 
  ways 
  in 
  which 
  I 
  attempted 
  to 
  obviate 
  the 
  difficulty. 
  

  

  With 
  regard 
  to 
  Mr. 
  Iyengar's 
  Paraformol, 
  if 
  the 
  water 
  needs 
  filtra- 
  

   tion 
  it 
  is 
  useless 
  where 
  water 
  supply 
  comes 
  from 
  tanks. 
  A 
  chatty 
  dipped 
  

   into 
  the 
  tank 
  collects 
  much 
  of 
  the 
  surface 
  water 
  and 
  breaks 
  the 
  film. 
  

  

  What 
  is 
  its 
  specific 
  gravity 
  ? 
  Will 
  it 
  rise 
  if 
  once 
  put 
  down 
  ? 
  

  

  It 
  is 
  heavier 
  than 
  water, 
  but 
  when 
  it 
  is 
  powdered 
  it 
  remains 
  on 
  the 
  

   surface. 
  Once 
  it 
  goes 
  down 
  it 
  will 
  never 
  come 
  up. 
  

  

  What 
  will 
  be 
  the 
  effect 
  of 
  rain 
  on 
  the 
  film 
  of 
  mercurous 
  chloride 
  'I 
  

  

  I 
  do 
  not 
  kaow. 
  

  

  Stegomyia 
  larvae 
  are 
  bottom-feeders 
  ; 
  but 
  they 
  die. 
  How 
  do 
  the 
  

   particles 
  on 
  the 
  surface 
  kill 
  ? 
  It 
  is 
  important 
  to 
  know 
  whether 
  they 
  are 
  

   killed 
  by 
  particles 
  floating 
  or 
  sunk. 
  *S'. 
  albopicta 
  feeds 
  on 
  solid 
  matter 
  

   at 
  the 
  bottom 
  and 
  therefore 
  probably 
  does 
  by 
  eating 
  sunlcen 
  particles. 
  

   The 
  auction 
  of 
  mercury 
  salts 
  is 
  curious. 
  They 
  are 
  very 
  insoluble 
  but 
  have 
  

   a 
  powerful 
  effect 
  on 
  the 
  human 
  intestines 
  ; 
  what 
  happens 
  m 
  the 
  human 
  

   intestine, 
  nobody 
  knows. 
  Did 
  the 
  larvae 
  show 
  any 
  symptoms 
  'i 
  

  

  I 
  can 
  only 
  give 
  results 
  and 
  have 
  concluded 
  that 
  probably 
  the 
  salt 
  

   acts 
  through 
  the 
  mouth. 
  The 
  larvae 
  became 
  sluggish 
  before 
  they 
  died. 
  

   In 
  the 
  graphs 
  I 
  have 
  shown 
  the 
  points 
  when 
  the 
  larvae 
  began 
  to 
  show 
  

   symptoms 
  of 
  sluggishness 
  ; 
  these 
  points 
  are 
  indicated 
  by 
  the 
  positions 
  

   at 
  which 
  the 
  lines 
  break. 
  

  

  To 
  settle 
  the 
  point 
  of 
  oral 
  or 
  other 
  action 
  the 
  intestines 
  of 
  dead 
  larvao 
  

   might 
  be 
  tested 
  for 
  mercury. 
  

  

  Did 
  you 
  try 
  shaking 
  up 
  the 
  mercury 
  salt 
  in 
  the 
  water 
  before 
  putting 
  

   the 
  larvae 
  in 
  'i 
  

  

  