﻿24.-OViPOSIT10N 
  IN 
  CULICID^.* 
  

   (Plate 
  XXXI-XXXV). 
  

  

  By 
  H. 
  N. 
  Sharma, 
  B.A., 
  and 
  S. 
  K. 
  Sen, 
  B.Sc. 
  

  

  Tliis 
  paper 
  deals 
  with 
  the 
  results 
  obtained 
  in 
  one 
  of 
  a 
  series 
  of 
  inquiries 
  

   on 
  the 
  part 
  played 
  by 
  chemical 
  and 
  physical 
  factors 
  in 
  determining 
  

   some 
  of 
  the 
  more 
  important 
  activities 
  of 
  insects. 
  

  

  The 
  mosquitos 
  selected 
  for 
  experiment 
  were 
  generally 
  Culex 
  fatiyans, 
  

   Culex 
  vishnui 
  and 
  Stegotnijia 
  albo'picta, 
  and 
  the 
  object 
  of 
  the 
  inquiry 
  was 
  

   to 
  ascertain 
  (1) 
  whether 
  choice 
  of 
  water 
  for 
  egg-laying 
  is, 
  in 
  these 
  mos- 
  

   quitos, 
  influenced 
  by 
  the 
  condition 
  of 
  the 
  water 
  as 
  regards 
  temperature, 
  

   osmotic 
  pressure, 
  and 
  surface-tension, 
  and 
  (2) 
  whether 
  their 
  choice 
  can 
  

   be 
  influenced 
  by 
  the 
  addition 
  of 
  small 
  quantities 
  of 
  sweet, 
  salt, 
  astrin- 
  

   gent, 
  or 
  alkaline 
  substances 
  to 
  the 
  water. 
  

  

  The 
  mosquitos 
  were 
  kept 
  in 
  a 
  wooden 
  frame 
  covered 
  with 
  netting 
  

   and 
  about 
  two 
  feet 
  long, 
  the 
  netting 
  being 
  provided 
  with 
  sleeves 
  for 
  

   convenience 
  of 
  manipulation. 
  In 
  the 
  cage 
  were 
  two 
  dishes 
  of 
  moist 
  

   banana 
  for 
  food, 
  and 
  round 
  glass 
  vessels 
  (3 
  inches 
  diam. 
  X 
  l^ 
  inches 
  

   high), 
  containing 
  water 
  or 
  the 
  various 
  solutions 
  for 
  the 
  reception 
  of 
  eggs. 
  

   In 
  the 
  experiment 
  dealing 
  with 
  the 
  effect 
  of 
  temperature, 
  the 
  arrange- 
  

   ment 
  was 
  as 
  shown 
  in 
  Plate 
  XXXI 
  . 
  The 
  lamps 
  were 
  switched 
  off 
  for 
  an 
  

   hour 
  every 
  day 
  between 
  five 
  and 
  six 
  in 
  the 
  the 
  evening, 
  and 
  fresh 
  ice 
  

   was 
  provided 
  twice 
  a 
  day 
  at 
  8 
  a.m., 
  and 
  6 
  p.m. 
  Temperatures 
  were 
  taken 
  

   at 
  8 
  A.M., 
  and 
  generally 
  also 
  at 
  8 
  p.m. 
  This 
  rough 
  arrangement 
  was 
  

   found 
  to 
  give 
  sufficiently 
  constant 
  temperatures 
  for 
  our 
  purpose 
  ; 
  the 
  

  

  * 
  The 
  observations 
  recorded 
  in 
  this 
  paper 
  were 
  started 
  at 
  the 
  suggestion 
  of 
  the 
  late 
  

   Mr. 
  I'. 
  M. 
  Howlett, 
  Imperial 
  Pathological 
  Entomologist, 
  the 
  object 
  of 
  the 
  inquiry 
  being 
  

   explained 
  in 
  the 
  introductory 
  portion 
  which 
  has 
  been 
  taken 
  from 
  the 
  notes 
  left 
  by 
  him. 
  

   It 
  will 
  be 
  seen 
  that 
  the 
  data 
  obtained 
  exhibited 
  a 
  wide 
  and 
  often 
  unintelligible 
  divergence 
  

   in 
  the 
  egg-laying 
  propensities 
  in 
  different 
  mosquitos, 
  and, 
  as 
  such, 
  the 
  publication 
  of 
  

   these 
  results 
  'should 
  perhaps 
  have 
  been 
  withlield 
  ; 
  but 
  as 
  the 
  observations 
  involved 
  a 
  

   large 
  amount 
  of 
  arduous 
  work 
  occupying 
  several 
  months, 
  it 
  has 
  been 
  considered 
  desirable 
  

   that 
  they 
  should 
  be 
  published, 
  even 
  if 
  merely 
  as 
  an 
  indication 
  of 
  the 
  possibilities 
  (or 
  

   otherwise) 
  of 
  this 
  line 
  of 
  work, 
  rather 
  than 
  be 
  altogether 
  lost 
  to 
  the 
  cause 
  of 
  entomolo- 
  

   gical 
  science. 
  Every 
  effort 
  has 
  been 
  made 
  to 
  condense 
  the 
  results, 
  not 
  only 
  by 
  omitting 
  

   details 
  but, 
  as 
  will 
  be 
  seen, 
  also 
  by 
  adopting 
  the 
  graphical 
  method 
  of 
  representation 
  ; 
  

   and, 
  as 
  such 
  no 
  particular 
  implication, 
  other 
  than 
  a 
  mere 
  simplified 
  presentation 
  of 
  

   results, 
  is 
  to 
  be 
  sought 
  in 
  these 
  curves. 
  Where 
  we 
  have 
  attempted 
  to 
  deduce 
  a 
  con- 
  

   clusion, 
  we 
  have 
  done 
  so 
  only 
  on 
  the 
  basis 
  of 
  an 
  average 
  of 
  large 
  numbers 
  of 
  observa- 
  

   tions, 
  and, 
  even 
  then, 
  wo 
  should 
  be 
  far 
  from 
  insisting 
  on 
  its 
  unconditional 
  acceptance. 
  

  

  Except 
  where 
  otlierwise 
  stated 
  all 
  remarks 
  relate 
  to 
  Sle(jonii/iu 
  albopicta. 
  

  

  All 
  the 
  series 
  of 
  experiments 
  enumerated 
  in 
  this 
  paper 
  were 
  initiated 
  ))y 
  the 
  late 
  Mr. 
  

   Howlett 
  but 
  no 
  record 
  is 
  available 
  to 
  show 
  what 
  principle 
  underlay 
  the 
  selection 
  of 
  the 
  

   chemicals 
  experimented 
  with. 
  The 
  First 
  Author 
  was 
  responsible 
  for 
  most 
  of 
  the 
  oviposi- 
  

   tion 
  figures 
  except 
  the 
  temperature 
  and 
  a 
  few 
  more 
  figures 
  which 
  were 
  obtained 
  by 
  the 
  

   Second 
  Author 
  who 
  also 
  wrote 
  up 
  the 
  materials 
  and 
  prepared 
  the 
  graphs, 
  and 
  gave 
  

   what 
  interpretation 
  he 
  considered 
  possible 
  to 
  the 
  selection 
  of 
  the 
  chemicals. 
  

  

  ( 
  192 
  ) 
  

  

  