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  A 
  NOTE 
  ON 
  A 
  BEETLE 
  WHICH 
  PREYS 
  ON 
  MOSQUITO 
  LARVAE. 
  

  

  By 
  J. 
  W. 
  S. 
  Macfie. 
  

  

  Last 
  July 
  (1922) 
  a 
  species 
  of 
  beetle, 
  kindly 
  identified 
  by 
  Dr. 
  G. 
  A. 
  K. 
  Marshall 
  

   as 
  the 
  Tiger 
  beetle, 
  Cicindela 
  octogiittata, 
  F., 
  a 
  common 
  Tropical 
  African 
  species, 
  

   was 
  observed 
  to 
  prey 
  on 
  mosquito 
  larvae 
  at 
  Accra, 
  in 
  the 
  Gold 
  Coast. 
  As 
  this 
  habit 
  

   of 
  the 
  beetle 
  does 
  not 
  appear 
  to 
  have 
  been 
  previously 
  observed, 
  and 
  as 
  it 
  is 
  perhaps 
  

   remarkable 
  that 
  it 
  should 
  prey 
  on 
  such 
  entirely 
  aquatic 
  insects 
  as 
  mosquito 
  larvae, 
  

   the 
  following 
  brief 
  note 
  may 
  prove 
  of 
  interest. 
  

  

  The 
  beetles 
  are 
  commonly 
  seen 
  in 
  the 
  Gold 
  Coast 
  at 
  the 
  muddy 
  margins 
  of 
  pools 
  

   and 
  lagoons, 
  and 
  at 
  the 
  time 
  the 
  observations 
  were 
  made 
  were 
  very 
  abundant 
  on 
  

   the 
  mud 
  flats 
  left 
  by 
  the 
  receding 
  of 
  the 
  water 
  a 
  little 
  above 
  the 
  head 
  of 
  the 
  Accra 
  

   lagoon, 
  and 
  especially 
  at 
  the 
  margins 
  of 
  the 
  little 
  pools 
  and 
  puddles 
  left 
  in 
  these 
  

   mud 
  flats 
  and 
  on 
  the 
  level 
  ground 
  near 
  them. 
  They 
  range 
  about 
  over 
  the 
  mud 
  

   apparently 
  in 
  search 
  of 
  prey, 
  moving 
  rapidly, 
  and 
  being 
  very 
  wary 
  they 
  become 
  

   alarmed 
  and 
  fly 
  away 
  if 
  incautiously 
  approached. 
  They 
  also 
  frequent 
  the 
  water's 
  

   edge 
  and 
  are 
  often 
  seen 
  in 
  long 
  rows 
  lining 
  the 
  margins 
  of 
  shallow 
  pools 
  and 
  puddles. 
  

   It 
  is 
  here 
  that 
  they 
  prey 
  on 
  mosquito 
  larvae, 
  for 
  these 
  pools 
  and 
  puddles 
  are 
  a 
  favourite 
  

   nursery 
  for 
  the 
  larvae 
  of 
  Anopheles 
  costalis, 
  Loew. 
  I 
  have 
  watched 
  them 
  for 
  hours 
  

   preying 
  on 
  these 
  larvae. 
  They 
  stand 
  actually 
  just 
  in 
  the 
  water, 
  very 
  alert, 
  with 
  

   their 
  antennae 
  slightly 
  divergent 
  and 
  directed 
  downwards 
  and 
  forwards. 
  It 
  is 
  the 
  

   movements 
  of 
  the 
  larvae 
  apparently 
  which 
  attract 
  their 
  attention, 
  when 
  with 
  a 
  

   swift 
  swoop 
  they 
  seize 
  their 
  prey, 
  usually 
  about 
  the 
  middle, 
  drag 
  it 
  from 
  the 
  water, 
  

   and 
  carry 
  it 
  a 
  few 
  inches 
  away 
  from 
  the 
  pool 
  to 
  devour 
  it. 
  Their 
  aim 
  is 
  not 
  unerring, 
  

   but 
  nevertheless 
  shows 
  a 
  considerable 
  degree 
  of 
  skill, 
  and 
  occasionally 
  they 
  plunge 
  

   so 
  deeply 
  for 
  their 
  prey 
  that 
  the 
  greater 
  part 
  of 
  the 
  head 
  is 
  submerged. 
  They 
  prey 
  

   not 
  only 
  on 
  Anopheline, 
  but 
  also 
  upon 
  Culicine 
  larvae 
  (e.g., 
  Culex 
  fatigans, 
  Wied., 
  

   C. 
  thalassins, 
  Theo., 
  and 
  Stegomyia 
  fasciata, 
  F.), 
  seizing 
  them 
  usually 
  by 
  the 
  posterior 
  

   extremity, 
  and 
  are 
  equally 
  partial 
  to 
  pupae, 
  which 
  they 
  grip 
  by 
  the 
  cephalo-thorax. 
  

  

  Mosquito 
  larvae 
  are 
  not 
  their 
  only 
  victims. 
  I 
  have 
  actually 
  seen 
  them 
  capture 
  

   and 
  carry 
  off 
  a 
  species 
  of 
  water-boatman, 
  Anisops 
  sp., 
  and 
  they 
  are 
  frequently 
  seen 
  

   in 
  places 
  where 
  there 
  are 
  no 
  mosquito 
  larvae 
  and 
  appear 
  to 
  find 
  there 
  some 
  sort 
  of 
  

   provender, 
  the 
  nature 
  of 
  which 
  I 
  have 
  been 
  unable 
  to 
  ascertain. 
  Dr. 
  Marshall, 
  

   however, 
  informs 
  me 
  that 
  he 
  has 
  observed 
  an 
  allied 
  species 
  in 
  Rhodesia 
  frequenting 
  

   the 
  edges 
  of 
  muddy 
  puddles 
  and 
  catching 
  various 
  small 
  insects, 
  especially 
  Diptera, 
  

   that 
  run 
  about 
  on 
  the 
  mud. 
  On 
  one 
  occasion 
  I 
  found 
  the 
  beetles 
  completely 
  sur- 
  

   rounding 
  the 
  margin 
  of 
  a 
  shallow 
  puddle 
  crowded 
  with 
  tadpoles. 
  Although 
  I 
  watched 
  

   them 
  for 
  an 
  hour 
  I 
  never 
  saw 
  them 
  actually 
  secure 
  any 
  of 
  the 
  tadpoles, 
  which 
  perhaps 
  

   were 
  too 
  large 
  and 
  powerful 
  for 
  them, 
  but 
  they 
  did 
  attack 
  a 
  few 
  I 
  removed 
  from 
  

   the 
  pool 
  and 
  laid 
  on 
  the 
  mud 
  at 
  one 
  side, 
  nipping 
  them 
  repeatedly 
  and 
  sometimes 
  

   flying 
  off 
  with 
  them 
  and 
  devouring 
  them 
  at 
  leisure. 
  This 
  observation 
  suggests 
  that 
  

   perhaps 
  they 
  had 
  been 
  accustomed 
  to 
  prey 
  on 
  them 
  at 
  an 
  earlier 
  stage 
  of 
  their 
  

   development. 
  

  

  