﻿BREEDING-PLACES 
  01" 
  Till- 
  ANOI'IIKI.IN'KS 
  or 
  \i.\l 
  \.v.\. 
  »■{ 
  

  

  within 
  the 
  group 
  of 
  Anophelines 
  which 
  are 
  said 
  to 
  have 
  a 
  preference 
  for 
  breeding 
  in 
  

   small 
  open 
  pools 
  or 
  open 
  hilly 
  country. 
  But 
  a 
  collection 
  of 
  larvae 
  from 
  the 
  bottom 
  of 
  

   an 
  old 
  boat, 
  which 
  contained 
  a 
  mixture 
  of 
  rain-water 
  and 
  water 
  that 
  had 
  leaked 
  into 
  it 
  

   from 
  a 
  fishpond 
  on 
  which 
  it 
  floated, 
  afforded 
  162 
  larvae 
  of 
  this 
  species 
  in 
  pure 
  culture 
  : 
  

   and 
  a 
  collection, 
  made 
  at 
  the 
  same 
  time 
  from 
  the 
  fishpond 
  itself, 
  yielded 
  35 
  larvae 
  of 
  

   A. 
  vagus 
  also, 
  132 
  larvae 
  of 
  A. 
  hyrcanus, 
  36 
  of 
  A. 
  barbirostris, 
  6 
  of 
  .1. 
  fuliginosus 
  and 
  

   one 
  of 
  A. 
  aconitus. 
  

  

  A 
  collection 
  on 
  1st 
  December 
  1920 
  from 
  small 
  muddy 
  pools 
  afforded 
  368 
  larvae 
  of 
  

   .4. 
  vagus 
  with 
  2 
  of 
  .4. 
  kochi, 
  62 
  of 
  A. 
  hyrcanus 
  and 
  28 
  of 
  A. 
  barbirostris, 
  the 
  two 
  latter 
  

   species 
  being 
  usually 
  found 
  in 
  large 
  swampy 
  pools 
  or 
  low-lying 
  country. 
  In 
  another 
  

   collection, 
  made 
  on 
  15th 
  April 
  1920 
  from 
  small 
  muddy 
  pools 
  in 
  the 
  same 
  locality, 
  

   30 
  larvae 
  of 
  A. 
  barbirostris, 
  4 
  of 
  .4. 
  hyrcanus 
  and 
  3 
  only 
  of 
  A. 
  vagus 
  were 
  obtained. 
  

   An 
  answer 
  to 
  the 
  speculation 
  as 
  to 
  whether 
  in 
  a 
  period 
  of 
  drought 
  A. 
  vagus 
  ceased 
  to 
  

   breed, 
  owing 
  to 
  an 
  absence 
  of 
  its 
  favoured 
  breeding-places, 
  small 
  muddy 
  pools, 
  or 
  

   availed 
  itself 
  of 
  other 
  waters, 
  was 
  provided 
  by 
  a 
  collection 
  made 
  at 
  such 
  a 
  season, 
  in 
  a 
  

   fishpond. 
  Here 
  were 
  secured, 
  on 
  29th 
  March 
  1920, 
  244 
  larvae 
  of 
  A. 
  vagus 
  with 
  53 
  of 
  

   A. 
  hyrcanus 
  and 
  3 
  of 
  A. 
  barbirostris, 
  whereas 
  in 
  seven 
  collections 
  made 
  from 
  the 
  same 
  

   pond 
  up 
  to 
  22nd 
  of 
  the 
  month, 
  a 
  wet 
  period, 
  there 
  were 
  only 
  72 
  larvae 
  of 
  A. 
  vagus 
  

   in 
  a 
  total 
  of 
  1 
  ,697 
  other 
  larvae. 
  A 
  further 
  collection 
  from 
  the 
  fishpond, 
  on 
  26th 
  August 
  

   1920, 
  afforded 
  no 
  fewer 
  than 
  628 
  larvae 
  of 
  A 
  . 
  vagus, 
  2oiA. 
  subpictus, 
  5oiA 
  .fuliginosus, 
  

   18 
  of 
  A. 
  barbirostris 
  and 
  105 
  of 
  A. 
  sinensis. 
  

  

  It 
  is 
  evident, 
  then, 
  that 
  no 
  conclusions 
  sufficiently 
  valid 
  to 
  be 
  of 
  any 
  practical 
  

   value 
  can 
  be 
  drawn 
  as 
  to 
  the 
  species 
  of 
  larvae 
  to 
  be 
  found 
  in 
  a 
  breeding-place 
  from 
  

   characteristics 
  of 
  its 
  environment. 
  Notwithstanding 
  this, 
  the 
  object 
  of 
  the 
  present 
  

   paper 
  is 
  to 
  advance 
  the 
  argument 
  that 
  Anophelines 
  are 
  not 
  merely 
  selective 
  " 
  to 
  some 
  

   extent," 
  but 
  are 
  selective 
  to 
  a 
  high 
  degree, 
  and 
  that 
  this 
  selective 
  tendency 
  depends 
  on 
  

   other 
  factors 
  than 
  the 
  mere 
  environment 
  of 
  a 
  breeding-place. 
  It 
  will 
  be 
  shown 
  in 
  the 
  

   case 
  of 
  A 
  . 
  aconitus, 
  to 
  which 
  study 
  was 
  largely 
  restricted, 
  that 
  choice 
  has 
  been 
  constant 
  

   over 
  a 
  very 
  long 
  period 
  of 
  time, 
  there 
  being 
  other 
  comparable 
  situations 
  available 
  

   in 
  which 
  none 
  of 
  these 
  larvae 
  were 
  found. 
  An 
  attempt 
  will 
  be 
  made 
  to 
  consider 
  

   some 
  of 
  the 
  factors 
  on 
  which 
  such 
  choice 
  may 
  well 
  depend. 
  

  

  A. 
  aconitus 
  is 
  one 
  of 
  the 
  dominant 
  Anophelines 
  of 
  the 
  Malay 
  States. 
  In 
  Kuala 
  

   Lampur 
  it 
  is 
  certainly 
  the 
  most 
  abundant 
  of 
  all, 
  a 
  total 
  of 
  no 
  less 
  than 
  5,753 
  adult 
  

   specimens 
  out 
  of 
  a 
  grand 
  total 
  of 
  11,001 
  of 
  these 
  mosquitos 
  having 
  been 
  obtained 
  in 
  

   about 
  nine 
  months 
  by 
  the 
  writer 
  in 
  the 
  course 
  of 
  some 
  work 
  having 
  as 
  its 
  object 
  

   the 
  determination 
  of 
  the 
  seasonal 
  prevalence, 
  if 
  any, 
  of 
  mosquitos. 
  It 
  is 
  an 
  open- 
  

   country 
  breeder 
  and, 
  as 
  has 
  been 
  pointed 
  out 
  by 
  Dr. 
  Hacker 
  in 
  the 
  report 
  referred 
  to, 
  

   has 
  a 
  preference 
  for 
  large 
  reedy 
  ponds 
  and 
  open 
  deep 
  swamps, 
  being 
  there 
  associated 
  

   with 
  A. 
  barbirostris, 
  A. 
  hyrcanus, 
  A. 
  fuliginosus, 
  A. 
  subpictus 
  var. 
  malayensis 
  and 
  some 
  

   other 
  species. 
  

  

  For 
  the 
  purpose 
  of 
  estimating 
  the 
  constancy 
  of 
  this 
  Anopheline 
  in 
  her 
  selection 
  of 
  a 
  

   breeding-place 
  it 
  was 
  arranged 
  that 
  collections, 
  to 
  include 
  all 
  Anopheline 
  larvae, 
  should 
  

   be 
  made 
  at 
  a 
  particular 
  place, 
  a 
  large 
  open 
  reedy 
  swamp 
  in 
  low-lying 
  ground 
  on 
  the 
  out- 
  

   skirts 
  of 
  the 
  town 
  and 
  subject 
  to 
  periodic 
  inundation 
  by 
  the 
  overflow 
  from 
  various 
  

   streams. 
  During 
  a 
  period 
  of 
  drought 
  it 
  became 
  dry 
  over 
  a 
  large 
  area, 
  but 
  water 
  was 
  

   constantly 
  found 
  in 
  the 
  small 
  open 
  ponds 
  which 
  still 
  remained. 
  In 
  this 
  swamp 
  pre- 
  

   liminary 
  examinations 
  had 
  shown 
  the 
  presence 
  of 
  a 
  large 
  number 
  of 
  these 
  particular 
  

   larvae. 
  Collections 
  were 
  made 
  here 
  at 
  irregular 
  intervals 
  during 
  October 
  up 
  to 
  the 
  

   20th. 
  Thereafter 
  they 
  were 
  made 
  twice 
  weekly 
  by 
  the 
  same 
  number 
  of 
  collectors, 
  

   seven 
  ; 
  working 
  on 
  each 
  occasion 
  for 
  the 
  same 
  period 
  of 
  time, 
  about 
  three 
  hours. 
  

  

  Until 
  the 
  absolute 
  certainty 
  of 
  their 
  determination 
  by 
  microscopic 
  examination 
  

   had 
  been 
  realised, 
  the 
  larvae 
  in 
  each 
  collection 
  were 
  determined 
  by 
  breeding 
  out. 
  

   When, 
  after 
  an 
  examination 
  of 
  hundreds, 
  no 
  single 
  error 
  had 
  been 
  found 
  (for 
  species 
  

   difficult 
  to 
  determine 
  by 
  larval 
  examination 
  did 
  not 
  come 
  into 
  consideration) 
  this 
  

  

  (6160) 
  a2 
  

  

  