﻿144 
  W. 
  A. 
  LAMBORN. 
  

  

  month, 
  of 
  a 
  number 
  of 
  larvae 
  varying 
  in 
  length 
  from 
  1-3 
  mm. 
  In 
  the 
  case 
  of 
  another 
  

   family 
  of 
  this 
  species, 
  the 
  ova 
  were 
  deposited 
  on 
  11th 
  May 
  and 
  the 
  young 
  larvae 
  were 
  

   first 
  seen 
  on 
  13th 
  May. 
  The 
  family 
  did 
  not 
  thrive. 
  But 
  on 
  21st 
  May 
  it 
  consisted 
  of 
  

  

  1 
  larva 
  about 
  1 
  mm. 
  in 
  length, 
  as 
  small 
  as 
  if 
  it 
  had 
  recently 
  hatched 
  ; 
  another 
  

   4 
  mm. 
  in 
  length, 
  and 
  thus 
  well 
  on 
  the 
  way 
  to 
  maturity 
  ; 
  1 
  pupa, 
  a 
  few 
  hours 
  in 
  this 
  

   stage 
  of 
  development 
  ; 
  and 
  of 
  a 
  male 
  imago, 
  just 
  emerged. 
  

  

  A 
  more 
  striking 
  instance 
  of 
  disparity 
  in 
  development 
  occurred 
  in 
  a 
  family 
  bred 
  

   from 
  ova 
  deposited 
  during 
  the 
  night 
  of 
  13th 
  May 
  by 
  another 
  A. 
  vagus. 
  Unfortunately 
  

   no 
  note 
  as 
  to 
  the 
  hatching 
  of 
  the 
  larvae 
  was 
  made, 
  but 
  on 
  19th 
  May 
  when 
  they 
  were 
  

   transferred 
  to 
  new 
  water 
  it 
  was 
  recorded 
  that 
  the 
  larvae 
  varied 
  very 
  considerably 
  

   in 
  size, 
  some 
  being 
  barely 
  2 
  mm. 
  in 
  length, 
  as 
  if 
  newly 
  hatched, 
  and 
  others 
  5 
  mm. 
  

   in 
  length, 
  and 
  certainly 
  more 
  than 
  three-quarters 
  grown. 
  By 
  2nd 
  June, 
  7 
  of 
  these 
  

   had 
  pupated 
  and 
  the 
  imagos 
  had 
  duly 
  emerged 
  ; 
  the 
  rest 
  of 
  the 
  family 
  then 
  consisted, 
  

   after 
  17 
  days, 
  of 
  2 
  larvae, 
  one 
  6 
  mm. 
  in 
  length, 
  the 
  other 
  2 
  mm. 
  only. 
  The 
  diminutive 
  

   size 
  of 
  the 
  smaller 
  larva 
  was 
  not 
  due 
  to 
  any 
  delay 
  in 
  hatching 
  from 
  the 
  egg, 
  for 
  search 
  

   was 
  made 
  for 
  any 
  unhatched 
  ova 
  on 
  21st 
  May, 
  when 
  the 
  only 
  4 
  found 
  were 
  removed. 
  

  

  The 
  following 
  were 
  among 
  the 
  irregularities 
  in 
  development 
  noted 
  in 
  the 
  case 
  

   of 
  a 
  number 
  of 
  A. 
  maculatus 
  families 
  : 
  The 
  female 
  parent, 
  in 
  one 
  case, 
  laid 
  on 
  19th 
  

   June 
  approximately 
  143 
  ova, 
  and 
  two 
  days 
  later 
  it 
  was 
  thought 
  that 
  all 
  had 
  hatched. 
  

   At 
  all 
  events, 
  all 
  the 
  larvae 
  found 
  on 
  23rd 
  June 
  were 
  then 
  transferred, 
  one 
  by 
  one, 
  to 
  

   four 
  bowls, 
  in 
  which, 
  all 
  being 
  under 
  similar 
  conditions, 
  41 
  ultimately 
  attained 
  

   maturity. 
  The 
  first 
  imago, 
  a 
  male, 
  emerged 
  during 
  the 
  night 
  of 
  4th 
  July, 
  the 
  life-cycle 
  

   having 
  therefore 
  occupied 
  14 
  days. 
  The 
  other 
  imagos 
  came 
  out 
  at 
  almost 
  daily 
  

   intervals 
  right 
  up 
  to 
  29th 
  July, 
  the 
  life-cycle 
  of 
  the 
  last 
  one 
  having 
  occupied 
  no 
  less 
  

   than 
  39 
  days. 
  There 
  was, 
  further, 
  some 
  evidence 
  that 
  the 
  cycle 
  might 
  be 
  extended 
  

   over 
  a 
  considerably 
  longer 
  period 
  ; 
  for 
  at 
  the 
  end 
  of 
  the 
  39 
  days 
  there 
  were 
  still 
  

  

  2 
  surviving 
  larvae, 
  one 
  of 
  which 
  died 
  during 
  the 
  night 
  of 
  10th 
  August, 
  after 
  a 
  life 
  

   lasting 
  50 
  days 
  ; 
  the 
  second 
  survived 
  a 
  further 
  five 
  days. 
  The 
  interest 
  of 
  this 
  particular 
  

   observation 
  lies, 
  not 
  only 
  in 
  the 
  marked 
  degree 
  of 
  irregularity 
  of 
  development, 
  but 
  

   also 
  in 
  its 
  effect 
  in 
  having 
  ensured 
  the 
  emergence 
  of 
  individual 
  Anophelines 
  of 
  the 
  

   same 
  parentage 
  throughout 
  a 
  long 
  interval 
  of 
  time 
  comprising 
  both 
  wet 
  and 
  dry 
  

   seasons, 
  the 
  ova 
  having 
  been 
  laid 
  towards 
  the 
  end 
  of 
  a 
  wet 
  period. 
  

  

  In 
  the 
  case 
  of 
  a 
  family 
  bred 
  from 
  ova 
  laid 
  on 
  28th 
  May 
  by 
  an 
  A. 
  fuliginosus, 
  

   all 
  hatched 
  within 
  24 
  hours 
  of 
  each 
  other 
  and 
  were 
  kept 
  in 
  the 
  same 
  bowl. 
  The 
  first 
  

   of 
  the 
  offspring, 
  a 
  male, 
  emerged 
  during 
  the 
  night 
  of 
  8th 
  June, 
  the 
  life-cycle 
  from 
  

   egg 
  to 
  imago 
  having 
  occupied 
  11 
  days. 
  Thereafter 
  imagos 
  continued 
  to 
  emerge, 
  

   one 
  or 
  two 
  almost 
  daily, 
  up 
  till 
  the 
  night 
  of 
  18th 
  June, 
  21 
  days, 
  when 
  the 
  last 
  imago, 
  

   a 
  female, 
  came 
  out. 
  The 
  life-cycle, 
  therefore, 
  of 
  this 
  female 
  had 
  occupied 
  double 
  the 
  

   time 
  of 
  the 
  first 
  ; 
  and 
  had 
  it 
  not 
  been 
  for 
  the 
  death 
  of 
  the 
  single 
  remaining 
  pupa, 
  

   the 
  emergence 
  of 
  which 
  was 
  due 
  in 
  the 
  night 
  of 
  22nd 
  June, 
  the 
  length 
  of 
  the 
  cycle 
  

   would, 
  indeed, 
  have 
  been 
  more 
  than 
  doubled. 
  

  

  The 
  following 
  case 
  shows 
  that 
  the 
  factors 
  affecting 
  the 
  length 
  of 
  the 
  life-cycle 
  

   are 
  both 
  irregularity 
  in 
  hatching 
  and 
  irregularity 
  in 
  growth 
  of 
  the 
  larvae. 
  The 
  ova 
  

   deposited 
  by 
  an 
  A. 
  kochi 
  on 
  10th 
  May, 
  and 
  all 
  kept 
  in 
  the 
  same 
  bowl 
  with 
  the 
  water 
  

   unchanged, 
  afforded 
  larvae 
  which, 
  ten 
  days 
  later, 
  were 
  found 
  to 
  vary 
  from 
  a 
  bare 
  

  

  1 
  mm. 
  to 
  5 
  mm. 
  in 
  length. 
  On 
  18th 
  May 
  a 
  note 
  was 
  made 
  that 
  there 
  were 
  8 
  larvae, 
  

   and 
  on 
  21st 
  3 
  small 
  additional 
  ones 
  were 
  counted. 
  The 
  first 
  pupa 
  from 
  this 
  family 
  

   was 
  obtained 
  on 
  20th 
  May, 
  and 
  between 
  then 
  and 
  4th 
  June 
  there 
  were 
  8 
  others, 
  4 
  of 
  

   which 
  died, 
  and 
  4 
  yielded 
  imagos 
  (1 
  male 
  and 
  3 
  females). 
  On 
  31st 
  May 
  there 
  were 
  

  

  2 
  larvae 
  only, 
  1 
  barely 
  4 
  mm. 
  long, 
  the 
  other 
  about 
  6 
  mm. 
  long. 
  On 
  7th 
  June' 
  there 
  

   was 
  discovered 
  in 
  addition 
  a 
  tiny 
  larva 
  looking 
  as 
  if 
  newly 
  hatched 
  and 
  unmistakably 
  

   of 
  this 
  species 
  by 
  reason 
  of 
  the 
  pearly 
  patch 
  on 
  the 
  thorax, 
  which 
  had 
  characterised 
  

   the 
  other 
  larvae 
  in 
  that 
  bowl 
  (a 
  white 
  one) 
  . 
  One 
  of 
  these 
  last 
  3 
  larvae 
  died 
  ; 
  the 
  

   second 
  pupated 
  on 
  the 
  night 
  of 
  10th 
  June, 
  no 
  less 
  than 
  one 
  month 
  from 
  the 
  date 
  on 
  

  

  